tag:blogger.com,1999:blog-41727965324623758102024-03-13T07:39:29.726-07:00Skeletal DrawingA blog dedicated to the science of reconstructing dinosaurs and other extinct life forms.Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.comBlogger43125tag:blogger.com,1999:blog-4172796532462375810.post-68186936351289640832013-07-07T14:57:00.003-07:002013-07-07T14:57:59.286-07:00Mass estimates: North vs South redux<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://4.bp.blogspot.com/-2V3xVXyPqBQ/UdnjIAdq0LI/AAAAAAAAUZ0/8qo26HkYdsA/s1600/giga+sue+scales.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="378" src="http://4.bp.blogspot.com/-2V3xVXyPqBQ/UdnjIAdq0LI/AAAAAAAAUZ0/8qo26HkYdsA/s640/giga+sue+scales.jpg" width="640" /></a></div>
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I have good news and bad news today - the bad news is this is not the post where you get an estimate of the mass of <em style="letter-spacing: 0px;">Spinosaurus</em>. I know, I know. And I'm sorry. Here's the good news: in preparation for a much deeper look at the challenges of estimating the mass of <em id="yui_3_10_1_1_1373232011228_23347" style="letter-spacing: 0px;">Spinosaurus</em>, I've produces far more rigorous mass estimates of <em style="letter-spacing: 0px;">Tyrannosaurus</em> and <em id="yui_3_10_1_1_1373232011228_23349" style="letter-spacing: 0px;">Giganotosaurus</em> from GDI, and I got some surprising results to share.</div>
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First, a word on that <em style="letter-spacing: 0px;"></em><a href="http://www.skeletaldrawing.com/home/super-spinosaurus6282013" id="yui_3_10_1_1_1373232011228_23352" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;"><em id="yui_3_10_1_1_1373232011228_23351" style="letter-spacing: 0px;">Spinosaurus</em> post</a> - I've heard from several of you that there is degree of anticipation for it, and I apologize for the delay. That said, you're going to get a much better post now instead. My original intention had been to do a more generic look at scaling up different types of theropods to the length of <em style="letter-spacing: 0px;">Spinsosaurus</em>, which would not have been very precise. size, Even worse, since it would have relied on other people's mass estimates it would have been comparing mass estimates derived from different methodologies, which threatened to make the whole process an act of futility. </div>
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Instead you will be getting mass estimates I've generated directly from my own skeletal reconstructions. The mass estimates I'm sharing today were produced using Graphic Double Integration (GDI), a technique that lets you estimate the volume of complex 3D objects by averaging many cross-sections together. If you are unfamiliar with the process, you can think of it as taking a balloon animal and using math to average it into a more normal oval-shaped balloon of the same volume to make it easier to measure. I won't go into detail on how to perform a GDI analysis, because the SV-POW team has already written up a really good tutorial <a href="http://svpow.com/2011/01/20/tutorial-11-graphic-double-integration-or-weighing-dinosaurs-on-the-cheap/" id="yui_3_10_1_1_1373232011228_23379" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;" target="_blank">here</a>, which you should definitely read if you want to do your own GDI analysis.</div>
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First: the reveal: </div>
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<a href="http://3.bp.blogspot.com/-PgIFCmrN1CY/UdnjQQ_m7-I/AAAAAAAAUZ8/jo2Oe7BNNMM/s1600/north+vs+south+redux.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="512" src="http://3.bp.blogspot.com/-PgIFCmrN1CY/UdnjQQ_m7-I/AAAAAAAAUZ8/jo2Oe7BNNMM/s640/north+vs+south+redux.jpg" width="640" /></a></div>
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Back when I posted the original <a href="http://www.skeletaldrawing.com/home/giant-theropods-north-vs-south772013" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;">North vs South</a> comparison I wrote up some general thoughts on the skeletals including:</div>
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3) Sue almost certainly had a higher mass than the <em style="letter-spacing: 0px;">Giganotosaurus</em> type specimen, as tyrannosaurs seem to have broader torsos for their size.</blockquote>
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4) So...that large isolated <em style="letter-spacing: 0px;">Giganotosaurus</em> jaw? It's not really clear how much bigger that individual is, because there isn't perfect linear scaling between it and the type specimen (the isolated jaw is proportionately a bit deeper). My "best fit" version indicates an animal about 6.5% longer than the type. That would result in an animal over 13 meters in length, and also one that would be heavier than Sue.</blockquote>
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I certainly hit point number three on the head, but it appears I was a bit too hasty when it came to proclaiming that there was evidence that MUCPv-95 was heavier than Sue. The reason this occurs can be seen in the top view silhouettes I show above (which, by the way, are the very images I used, so you have the "original data" so to speak). Tyrannosaurs have almost comically wide abdomens (and mine is not as broad as some other workers and some mounts show), while Giganotosaurus has the typical allosaur-grade torso.</div>
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I'm sure many of you will want at least a few more details, so here is another quick-hit list of items you may find of interest:</div>
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1) I used 46 equally-spaced sections front to aft. The tiny forelimbs only have a few cross-sections, while the hind legs have 10. </div>
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2) I added extra skin around both skeletals to avoid the "trying to make them as skinny as possible" concern (more on that in a future post).</div>
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3) The thighs and upper half of the forearms are measured as part of the torso. </div>
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4) I used a specific gravity of 1.0 (same as water) for the limbs and tail, and 0.9 for the neck and torso (remember that the torso includes part of the denser upper limbs in this GDI) . The head uses 0.8 to account for the sinuses and empty space in the mouth.</div>
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5) Although <em style="letter-spacing: 0px;">Tyrannosaurus</em> seems likely to have had stronger calves I used the exact same muscle reconstruction to try and make the comparison more of an apples to apples affair</div>
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<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-_O1CBeCYV0k/Udnjl6BkMgI/AAAAAAAAUaE/bXTZkWp81zE/s1600/Giganotosaurus_carolinii_DSC_2949.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="212" src="http://1.bp.blogspot.com/-_O1CBeCYV0k/Udnjl6BkMgI/AAAAAAAAUaE/bXTZkWp81zE/s320/Giganotosaurus_carolinii_DSC_2949.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">From <a href="http://commons.wikimedia.org/wiki/File:Giganotosaurus_carolinii_DSC_2949.jpg" target="_blank">Wikimedia Commons</a></td></tr>
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6) I'm sure that some will claim that <em id="yui_3_10_1_1_1373232011228_24848" style="letter-spacing: 0px;">Giganotosaurus</em> should have a wider torso or head, but the skull is already substantially wider than in <em id="yui_3_10_1_1_1373232011228_24846" style="letter-spacing: 0px;">Acrocanthosaurus</em> and matches up with more recent reconstructions of the skull, like the one you see here. Also note that if anything the torso should be smaller up front due to the diminutive pectoral girdle.</div>
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7) I must reiterate, the lower jaw fragment of MUCPv-95 does not come from an animal that is 8% larger than the type. In fact it honestly could be from an identically-sized animal that just has a more robust dentary, so scaling it up 6.5% (in linear dimensions) should if anything be seen as the upper bounds.</div>
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Conclusions: </h3>
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As near as I can tell, despite <em id="yui_3_10_1_1_1373232011228_24165" style="letter-spacing: 0px;">Tyrannosaurus</em> and <em style="letter-spacing: 0px;">Giganotosaurus</em> appearing similar in size in side view, there is little question that T. rex is actually the larger theropod based on known specimens. To be fair, there's only one good specimen of <em style="letter-spacing: 0px;">Giganotosaurus</em>, and it took most of a century to find Sue, so it's certainly possible that as additional specimens are collected we will find larger southern giants. As always, please remember we don't have a statistically valid population of specimens from any of these large dinosaurs, so we are only comparing individuals, not species.</div>
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And finally, remember that no one study has magical knowledge of the "real" mass of extinct organisms. I feel confident that the GDI analysis I've performed accurately represents the volume of my own skeletal reconstructions, but obviously it reflects my own assumptions about skeletal articulation and soft-tissue anatomy. There is still substantial variation between published mass estimates; in particular the the numbers I'm publishing here are a bit lower than those given in the recent (and excellent) <a href="http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0026037" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;" target="_blank">paper</a> on computational analysis of <em id="yui_3_10_1_1_1373232011228_24914" style="letter-spacing: 0px;">T. rex</em> by John (<a href="http://whatsinjohnsfreezer.com/" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;" target="_blank">of the freezer</a>) Hutchinson and colleagues.</div>
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I'll be taking a look at the underlying reasons for that, along with the unique challenges that Spinosaurus holds for GDI analysis in my next post. When that's done I'll get around to putting up my mass estimate of the Fisher King. Now I'd best go finish those calculations.</div>
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And remember, you should be switching to <a href="http://www.skeletaldrawing.com/home/mass-estimates-north-vs-south-redux772013" target="_blank">reading this</a> on my new official blog at <a href="http://skeletaldrawing.com/">SkeletalDrawing.com</a> at your earliest convenience!</div>
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Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com3tag:blogger.com,1999:blog-4172796532462375810.post-46080443101892197442013-06-27T08:21:00.001-07:002013-06-27T08:21:08.558-07:00Assessing Alamosaurus<div dir="ltr" style="text-align: left;" trbidi="on">
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Today let's look at another one of our <a href="http://www.skeletaldrawing.com/home/2013/06/the-biggest-of-big.html" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;">thundering giants,</a> <em style="letter-spacing: 0px;"><a href="http://en.wikipedia.org/wiki/Alamosaurus" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;" target="_blank">Alamosaurus sanjuanensis</a></em>. <em style="letter-spacing: 0px;">Alamosaurus</em> is known from quite good remains (for a titanosaur), and some fragmentary remains may be close to the largest known dinosaur. How certain is this reconstruction? Much better than <em style="letter-spacing: 0px;"><a href="http://www.skeletaldrawing.com/home/2013/6/20/the-problem-with-puertasaurus" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;">Puertasaurus</a></em>, but there are still a couple of layers of inference needed to get there.</div>
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<span style="letter-spacing: 0px; line-height: 1.6em;">Until recently </span><em id="yui_3_10_1_1_1372312121743_16296" style="letter-spacing: 0px; line-height: 1.6em;">Alamosaurus</em><span style="letter-spacing: 0px; line-height: 1.6em;"> remains were all from varying sizes of subadults and juveniles. Since no one specimen is complete, it also requires a lot of cross-scaling. </span><span style="letter-spacing: 0px; line-height: 1.6em;">How to best cross-scale <em style="letter-spacing: 0px;">Alamosaurus</em> is in and of itself something of a </span><a href="http://browse.deviantart.com/art/Alamosaurus-skeletal-344422788" style="color: #2777ae; letter-spacing: 0px; line-height: 1.6em; outline: none; text-decoration: none;" target="_blank">debate</a><span id="yui_3_10_1_1_1372312121743_16299" style="letter-spacing: 0px; line-height: 1.6em;">. A lot of the material has only been described in graduate theses or is referred to without being figured in scientific papers, so the choice is whether to believe those numbers or pursue a scaling closer to that of <em style="letter-spacing: 0px;"><a href="http://en.wikipedia.org/wiki/Opisthocoelicaudia" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;" target="_blank">Opisthocoelicaudia</a></em>, a titanosaur that is often recovered as a close relative of <em style="letter-spacing: 0px;">Alamosaurus</em>.</span></div>
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<span id="yui_3_10_1_1_1372312121743_16301" style="letter-spacing: 0px; line-height: 1.6em;">I am more closely following the traditional limb proportions for Alamosaurus for a couple of reasons. For starters I see little reason to doubt that the authors involved measured the specimens correctly, and if they did then I think they chose well when cross-scaling elements. Second, while I'm not involved enough with researching titanosaur family tree positions to take issue with aligning Alamosaurus with Opisthocoelicaudia, I do wonder how representative it is of the group, as in many ways it's just a bizarre titanosaur.</span></div>
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Cross-scaling assumptions in hand, cobbling the specimens together yields a skeleton that is known from good material almost everywhere except the skull, which results in the skeletal you see on the right. The last few years the <a href="http://www.perotmuseum.org/" id="yui_3_10_1_1_1372312121743_16315" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;" target="_blank">Perot Museum of Nature and Science</a> has been working on a very large specimen, that included an almost complete neck. Working from photos of the neck I was able to create the skeletal that I'm using in the poster and <a href="http://www.skeletaldrawing.com/sauropods-and-kin/" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;">sauropod skeletal gallery</a>. The neck seems to get more robust with age, which is interesting but perhaps not terribly surprising. There may be more of the PMNS skeleton preserved, but it has not been formally written up yet, so I'm only showing the bones that I was able to use.</div>
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Finally, there's the incomplete tibia from Mexico described in 2006. It's truly a monster in size - even a conservative estimate yields a length of 165 cm - that's a shin bone that is almost as tall as I am! Assuming that this really is <em style="letter-spacing: 0px;">Alamosaurus</em>, scaling up the adult specimen results in an animals that could have stretched 28-30 meters, and tipped the scales with the likes of <em style="letter-spacing: 0px;"><a href="http://en.wikipedia.org/wiki/Argentinosaurus" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;" target="_blank">Argentinosaurus</a></em> and <em style="letter-spacing: 0px;">Puertasaurus</em>.</div>
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Now <em style="letter-spacing: 0px;">that's</em> a thunder lizard! </div>
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References: </div>
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Rivera-Sylva, Guzman-Guitierrez, & Palomino-Sanchez, 2006. Preliminary Report on a vertebrate fossil assemblage from the Late Cretaceous of Chihuahua, Mexico. Hantkeniana 5.</div>
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Lehman and Coulson, 2002. A juvenile specimen of the sauropod dinosaur Alamosaurus sanjuanensis from the Upper Cretaceous of Big Bend National Park, Texas. Journal of Paleontology 76: 156–172.</div>
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Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com1tag:blogger.com,1999:blog-4172796532462375810.post-21300619262591585042013-06-21T10:56:00.002-07:002013-06-27T08:21:44.206-07:00The Problem with Puertasaurus<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://4.bp.blogspot.com/-7EGie9pss1I/UcSTrGJIRGI/AAAAAAAAUGU/yE9pO_Xfxmo/s1600/Puertasaurus.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="390" src="http://4.bp.blogspot.com/-7EGie9pss1I/UcSTrGJIRGI/AAAAAAAAUGU/yE9pO_Xfxmo/s640/Puertasaurus.jpg" width="640" /></a></div>
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When I released my <a href="http://www.skeletaldrawing.com/home/2013/06/the-biggest-of-big.html" id="yui_3_10_1_1_1371794778734_127508" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;">Thunder Lizards</a> size comparison I was asked why a few of the largest animals were rendered in gray, and when I would be making the actual skeletal available. Using gray silhouettes solved an aesthetic concern (the image was threatening to get too busy), but it turns out that those critters have another problem: they are not known from very incomplete remains.</div>
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So here is the skeletal of <em style="letter-spacing: 0px;">Puertasaurus</em> in all its "glory". I have a fully restored version as well, but it's not going to be making a public appearance, as frankly I don't want it to be separated from the rigorous version, as that could give off the impression that the animal is better known. In fact even this version is somewhat misleading, as the two tail vertebrae were reported but not figured or described - I don't actually know how big they were!</div>
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That's not to say the reconstruction is a fantasy - it's status as a <a href="http://en.wikipedia.org/wiki/Lognkosauria" id="yui_3_10_1_1_1371794778734_127506" style="color: #2777ae; letter-spacing: 0px; outline: none; text-decoration: none;" target="_blank">lognkosaur</a> seems secure, and we have very good remains of some of its relatives. And the neck and back vertebrae actually provide a pretty reasonable basis for scaling the largest parts of <em style="letter-spacing: 0px;">Puertasaurus</em>. That said, I feel it's important for scientists (and scientific illustrators) not to inadvertently mislead people about the level of inference involved.</div>
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So enjoy the skeletal, but please do so responsibly! </div>
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Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com0tag:blogger.com,1999:blog-4172796532462375810.post-91189129526802230732013-06-20T10:02:00.001-07:002013-06-27T08:31:19.100-07:00Check out my redesigned website!<div dir="ltr" style="text-align: left;" trbidi="on">
<div class="sqs-block html-block" data-block-json="{"wysiwyg":{"engine":"code","mode":"htmlmixed","isSource":false,"source":""},"html":"<p>If this isn't your first time to my website, you're probably noticing that things look quite a bit different around here. That's because after numerous fits and false starts, I finally got around to redesigning the site. I think the site is now quite a bit more attractive, but more importantly it is using modern web technology.&nbsp;</p>","engine":"visual"}" data-block-type="2" id="block-472c52aa64473f957ac1" style="background-color: white; clear: none; color: #777777; font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif; font-size: 14px; line-height: 22.390625px; padding-bottom: 24px; padding-left: 12px; padding-right: 12px; position: relative; word-wrap: break-word; z-index: 1;">
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Hello dear readers - I've completely overhauled my we updated my website, so if you haven't been there for awhile I encourage to check it out. I'll be adding more content in the coming days as well (I'm still porting over and updating some of the pages from the previous incarnation).<br />
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But I also will be incorporating my blog directly onto my site. In the near term I will be cross-posting updates to both Blogger and to the website, but in the medium term I hope you will update your bookmarks to my site instead.<br />
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If you want more info on the site (and it's history) hop below the fold.<br />
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Well, it was that time of the decade again. After numerous fits and false starts, I finally got around to redesigning my website. I think the site is now quite a bit more attractive, but more importantly it is using modern web technology. </div>
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<a href="http://www.skeletaldrawing.com/theropods" id="yui_3_10_1_1_1371746342126_554" style="color: #121212; text-decoration: none;"><img alt="Majungasaurus" class="" data-image-dimensions="5832x1804" data-image-focal-point="0.5,0.5" data-image="http://static.squarespace.com/static/51bf1cd3e4b0a897bf54112b/t/51c211c1e4b0b7d8b4b1d7cd/1371673033886/majungasaurus_updated.jpg" data-src="http://static.squarespace.com/static/51bf1cd3e4b0a897bf54112b/t/51c211c1e4b0b7d8b4b1d7cd/1371673033886/majungasaurus_updated.jpg" src="http://static.squarespace.com/static/51bf1cd3e4b0a897bf54112b/t/51c211c1e4b0b7d8b4b1d7cd/1371673033886/majungasaurus_updated.jpg?format=500w" style="border: 0px; left: 0px; max-width: 100%; position: absolute; top: 0px; vertical-align: middle; width: 447px;" /></a></div>
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<a href="http://www.skeletaldrawing.com/theropods" id="yui_3_10_1_1_1371746342126_554" style="color: #121212; text-decoration: none;">MAJUNGASAURUS</a></div>
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<div class="sqs-block html-block" data-block-json="{"wysiwyg":{"engine":"code","mode":"htmlmixed","isSource":false,"source":""},"html":"<p>What does this mean for you? For starters, it means I have finally brought my skeletals together (and updated) in one location. The underlying CMS is incredibly easy to update too, so those the galleries will be staying current. </p><p>The site is also getting more social. I've enabled commenting via the <a href=\"http://disqus.com/\" target=\"_blank\">Disqus</a> platform, so it's now a breeze to ask questions or interact with me or your fellow visitors. Don't worry, you can also comment anonymously - just remember that spam or comments that are rude to others will be moderated. If you want to share something social sharing is now more deeply integrated into the site.</p><p>I'm also integrating the blog directly into the website (in fact you're reading it right now!). I will cross-post to <a href=\"http://skeletaldrawing.blogspot.com/\" target=\"_blank\">Blogger</a> as well for a while, but in the medium term everything is going to be centered here. One question I have for all of you: how much do you like to see the blog front and center? Right now it's the home page, which is nice because you always see the latest content. On the other hand you need to spend time looking at the navigation bars to find other content. Do you like this, or is it preferable to have some static links on the front page to popular content, with the blog on another tab?</p><p>Finally, for those of you who are amused by how much the web changes, I saved some screen caps so we could take a stroll down Skeletal Drawing's memory lane:</p><h3>Skeletal Drawing 1.0</h3>","engine":"visual"}" data-block-type="2" id="block-2b74e0e00065c75eb90b" style="background-color: white; clear: none; color: #777777; font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif; font-size: 14px; line-height: 22.390625px; padding-bottom: 24px; padding-left: 12px; padding-right: 12px; position: relative; word-wrap: break-word; z-index: 1;">
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What does this mean for you? For starters, it means I have finally brought my skeletals together (and updated) in one location. The underlying CMS is incredibly easy to update too, so those the galleries will be staying current.</div>
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<span style="letter-spacing: 0px; line-height: 1.6em;">For those of you who are amused by how much the web changes, I saved some screen caps so we could take a stroll down Skeletal Drawing's memory lane:</span></div>
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SKELETAL DRAWING 1.0</h3>
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THAT'S <a href="http://www.youtube.com/watch?v=EVekNsgUqn4" style="color: #121212; text-decoration: none;" target="_blank">NOT A NAV BAR</a>, IT'S AN IMAGE FILE!</div>
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<div class="sqs-block html-block" data-block-json="{"wysiwyg":{"engine":"code","mode":"htmlmixed","isSource":false,"source":""},"html":"<p>Back in 2002 (that's right, this website is over a decade old, which is positively Paleozoic in terms of web history) I decided that I'd use a copy of <a href=\"http://en.wikipedia.org/wiki/Microsoft_frontpage\" target=\"_blank\">Microsoft's FrontPage</a> and try my hand at that fancy HTML stuff I'd read about, so I could put a few of my skeletal reconstructions on the interwebz. The result? A whole series of incredibly simple hand-coded pages that looked like this.</p><p>How \"hand coded\" was it? I didn't know how to make buttons(!), so for my navigation bar I actually created an image in Photoshop that had the image of a button(s) drawn on it. I then placed the hyperlinked text over the buttons so you could \"click\" them. Of course I had to make different images depending on how many \"buttons\" each page was supposed to have. &nbsp;</p><p>There was eventually a \"1.5\" version a couple years later, as I picked up a copy of Dreamweaver (just after Adobe bought it), and that had an automated script that generated simple image galleries automagically. I ended up with a website that looked the same, but had more content!</p><p></p><p></p><h3>Skeletal Drawing 2.0</h3><p>Around 2007, despite having shelled out money for Dreamweaver, I became aware that my website looked like it had been made in the previous century. I started reading up on spiffy concepts like <a href=\"http://en.wikipedia.org/wiki/Cascading_Style_Sheets\" target=\"_blank\">Cascading Style Sheets</a>, and realized that if I wanted the website to not suck I'd have learn to do more coding myself. That work eventually turned into the website that you would have seen until this one went live, and it was a slightly more primitive version of the image on the right.</p>","engine":"visual"}" data-block-type="2" id="block-5f0e65b79718c02c74fa" style="background-color: white; clear: none; color: #777777; font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif; font-size: 14px; line-height: 22.390625px; padding-bottom: 24px; padding-left: 12px; padding-right: 12px; position: relative; word-wrap: break-word; z-index: 1;">
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Back in 2002 (that's right, this website is a decade old, which is positively Paleozoic in terms of web history) I decided that I'd use a copy of <a href="http://en.wikipedia.org/wiki/Microsoft_frontpage" style="color: #121212; text-decoration: none;" target="_blank">Microsoft's FrontPage</a> and try my hand at that fancy HTML stuff I'd read about, so I could put a few of my skeletal reconstructions on the interwebz. The result? A whole series of incredibly simple hand-coded pages that looked like this.</div>
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How "hand coded" was it? I didn't know how to make buttons(!), so for my "navigation bar" I actually created an image in Photoshop that included the header and a gray nav bar "stip", and drew the image of button(s) on jpeg file! I then positioned hyperlinked text over the buttons so you could "click" them. I had to make different images depending on how many "buttons" each page was supposed to have, which naturally was a barrier to changing my website's navigation model.</div>
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There was eventually a "1.5" version a couple years later, as I picked up a copy of Dreamweaver (just after Adobe bought it), and that had an automated script that generated simple image galleries automagically. I ended up with a website that looked the same but had more content!</div>
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SKELETAL DRAWING 2.0</h3>
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Around 2007, despite having shelled out money for Dreamweaver, I became aware that my website looked like it had been made in the previous century. I started reading up on spiffy concepts like <a href="http://en.wikipedia.org/wiki/Cascading_Style_Sheets" style="color: #121212; text-decoration: none;" target="_blank">Cascading Style Sheets</a>, and realized that if I wanted the website to not suck I'd have learn to do more coding myself. That work eventually turned into the website that you would have seen until this one went live, and it was a slightly smaller and more primitive version of the image on the right.</div>
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<img class="" data-image-dimensions="1021x1070" data-image-focal-point="0.5,0.5" data-image="http://static.squarespace.com/static/51bf1cd3e4b0a897bf54112b/t/51c218a1e4b01f1752ec4d9f/1371674788843/SD%202.jpg" data-src="http://static.squarespace.com/static/51bf1cd3e4b0a897bf54112b/t/51c218a1e4b01f1752ec4d9f/1371674788843/SD%202.jpg" src="http://static.squarespace.com/static/51bf1cd3e4b0a897bf54112b/t/51c218a1e4b01f1752ec4d9f/1371674788843/SD%202.jpg?format=500w" style="border: 0px; cursor: pointer; left: 0px; max-width: 100%; position: absolute; top: 0px; vertical-align: middle; width: 447px;" /></div>
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<div class="sqs-block html-block" data-block-json="{"wysiwyg":{"engine":"code","mode":"htmlmixed","isSource":false,"source":""},"html":"<p>That made most of the website contemporary (by 2008ish standards)&nbsp;, but it was still painfully slow to add content, and the old image galleries made it so awful to update individual images that mostly I just didn't bother. Of course blogging had long since become a \"thing\", and websites were expected to generate content at a much faster rate.</p><p>I realized all of that about the time the website fully reached the version above. I had actually created ~85% of a \"2.5\" version of the website last year - it looked the same but ran on the popular CMS platform <a href=\"http://www.joomla.org/\" target=\"_blank\">Joomla</a>. Alas, for a variety of reasons (including improper backing up) I never launched it.</p><p></p><p></p><p></p><p></p><p></p><p></p><h3>Skeletal Drawing 3.0</h3><p>So here we are today. Gone are the tans and browns. The website is now mobile-friendly and made for rapid updating. I promise that you'll see more regular content, and you can always come here to get the latest versions of my skeletal reconstructions.&nbsp;</p><p>And as a final promise, I'll get back to blogging about dinosaurs, rather than web development. Please pass along any thoughts or comments on the new site below!</p><p>&nbsp;</p>","engine":"visual"}" data-block-type="2" id="block-1c029784ec3b619f9b34" style="background-color: white; clear: none; color: #777777; font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif; font-size: 14px; line-height: 22.390625px; padding-bottom: 0px; padding-left: 12px; padding-right: 12px; position: relative; word-wrap: break-word; z-index: 1;">
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That made the website look more contemporary (by 2008 standards) , but it was still painfully slow to add content and the old image galleries made it so awful to update individual images that mostly I just didn't bother. Of course blogging had long since become a "thing", and as a result websites were expected to generate content at a much faster rate.</div>
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I realized all of that about the time the website fully reached the version above. I created this Blogger site apart from the website to partially solve the "rate of content" problem while I turned to creating the next incarnation of the website. By last year I had actually created ~85% of a "2.5" version of the website - it looked the same but ran on the popular CMS platform <a href="http://www.joomla.org/" style="color: #121212; text-decoration: none;" target="_blank">Joomla</a>. Alas, for a variety of reasons (including miscommunication with the hosting company and improper backing up on my end) I never launched it.</div>
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SKELETAL DRAWING 3.0</h3>
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So here we are today. Gone are the tans and browns. The website is now mobile-friendly and made for rapid updating. I promise that you'll see more regular content, and you can always come here to get the latest versions of my skeletal reconstructions. <span style="letter-spacing: 0px; line-height: 1.6em;">And as a final promise, I'll get back to blogging about dinosaurs, rather than web development. Just remember that sooner or later the this blog will be put out to pasture in favor of the one on <a href="http://www.skeletaldrawing.com/" target="_blank">my website</a>.</span></div>
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Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com6tag:blogger.com,1999:blog-4172796532462375810.post-6738706670912956422013-06-14T11:55:00.001-07:002013-06-14T13:46:20.637-07:00The biggest of the big<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://3.bp.blogspot.com/-RPA_M5Ug5Rc/Ubtfij4CsTI/AAAAAAAAT-s/Y0af_8Zo0fo/s1600/Thunder+lizard+size+comparison.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="410" src="http://3.bp.blogspot.com/-RPA_M5Ug5Rc/Ubtfij4CsTI/AAAAAAAAT-s/Y0af_8Zo0fo/s640/Thunder+lizard+size+comparison.jpg" width="640" /></a></div>
<span id="docs-internal-guid-006e8c1e-4416-6b64-3ce7-9d006937da36"><span style="font-family: Arial; font-size: 15px; vertical-align: baseline; white-space: pre-wrap;">I don't know if that grabs your attention, but sorting out the size of giant sauropods sure grabs mine. Jump below the fold for some details on the critters in this image.</span></span><br />
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<a name='more'></a><div dir="ltr" style="line-height: 1.15; margin-bottom: 0pt; margin-top: 0pt;">
<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">First off, I need to admit that this is not all inclusive. The legendary </span><a href="http://en.wikipedia.org/wiki/Amphicoelias" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Amphicoelias fragillimus</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> will never be included (unless more material is found). I have not sufficiently nailed down the scaling of </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Argentinosaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> yet to include it, but early scaling makes it look like it's the same size or slightly smaller than </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Puertasaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> (which I did include).</span></div>
<b id="docs-internal-guid-006e8c1e-4415-ec31-4150-ec5a43a0c8d6" style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Note that most of these animals are only known from a single specimen (and often quite incomplete skeletons at that), which means that we don't really know what the size range of animals was in a living population. So keep in mind that while we can compare individual specimens, we can't say with any certainty that the biggest skeleton really came from the biggest sauropod species.</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Here are some other quick hits:</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">1) For </span><a href="http://www.skeletaldrawing.com/sauropods/supersaurus.htm" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">personal</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><a href="http://skeletaldrawing.com/supersaur_project/CLPV_II_Supersaurus.pdf" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">reasons</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> I love me some </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Supersaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. I've scaled the reconstruction to the size of the WDC specimen (32m), though the type specimen may have reached 34m in length. Either way it's the longest sauropod we can reasonably restore, though it certainly was not the heaviest (diplodocids tend to be fairly slab-sided compared to titanosaurs). </span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">2) The large NMMNH </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Diplodocus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> specimen (originally named </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Seismosaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">) is also very long (~30m) but probably even lighter in mass.</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">3) Diplodocids may rule the roost in length, but macronarians seems to (mostly) crush them in terms of mass. </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Puertasaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is currently my reigning champion; filling in the (extensive) missing elements with other </span><a href="http://en.wikipedia.org/wiki/Lognkosauria" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">lognkosaur</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> relatives leads to a 27 meter long animal that is clearly the heaviest of the group (I'll speculate maybe in the 60-70 tonne range, but treat that as arm waving until it's verified by volumetric or </span><a href="http://svpow.com/2011/01/20/tutorial-11-graphic-double-integration-or-weighing-dinosaurs-on-the-cheap/" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">double integration</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> analysis).</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">4) To elaborate on </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Argentinosaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> (not included above), it’s mostly in the same size range as </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Puertasaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">, but more basal titanosaurs have somewhat shorter tails (hence the smaller length) and the vertebrae aren't quite as wide as Puertasaurus, so the best guess is that it loses on both accounts to it's lognkosaur relative, if only by a weeeee bit.</span></div>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">5) I didn't include </span><a href="http://en.wikipedia.org/wiki/Paralititan" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Paralititan</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> but I did scale it (hey, there's only so much space). It's large, but appears to be somewhat smaller than the biggest </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Alamosaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> specimens.</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<div dir="ltr" style="line-height: 1.15; margin-bottom: 0pt; margin-top: 0pt;">
<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">6) Speaking of </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Alamosaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">, I spent a lot of time trying to sort out who had the biggest fragmentary remains between Fowler & Sullivan (</span><a href="http://www.app.pan.pl/archive/published/app56/app20100105.pdf" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">2010</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">) and Guzman-Gutierrez & Palomino-Sanchez (</span><a href="http://www.academia.edu/237780/Preliminary_Report_on_a_vertebrate_fossil_assemblage_from_the_Late_Cretaceous_of_Chihuahua_Mexico" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">2006</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">). It looks like the tibia from Mexico is the biggest, but the restored skeletal here is based on Fowler and Sullivan's largest specimen (an isolated tail vertebrae) which happens to be from animal almost exactly the same size as the specimen on display at the </span><a href="http://www.dallasnews.com/news/community-news/dallas/headlines/20120524-public-in-dallas-gets-sneak-peek-at-perot-museums-dinosaurs.ece" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Perot Museum of Nature and Science</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">.</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">6) </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Brachiosaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> has long been abandoned in discussions of who is the largest dinosaur, but I'm not sure that's a good idea. The skeletal above is restored to the size of the type specimen, but some of the Utah specimens may be larger. The very broad-gutted </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Puertasaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> probably ekes out a larger size, but with such small sample sizes I don't think </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Brachiosaurus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> can actually be ruled out.</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">7) The significantly less robust </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Giraffatitan</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> probably can be ruled out, despite being quite tall.</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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<div dir="ltr" style="line-height: 1.15; margin-bottom: 0pt; margin-top: 0pt;">
<span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">8) While titanosaurs are generally heavier than diplodocids, very large </span><a href="http://skeletaldrawing.blogspot.com/2012/04/yup-ok-apatosaurus-is-freakin-huge.html" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: italic; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Apatosaurus</span><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;"> specimens</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> appear to fit comfortably in the same size class. In addition to the </span><a href="http://svpow.com/2012/04/30/the-giant-oklahoma-apatosaurus-omnh-1670-redux/" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Oklahoma specimen</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> I have seen a few other (unpublished) apatosaur specimens that at least rival it in size.</span></div>
<b style="font-weight: normal;"><br /><span style="background-color: transparent; color: black; font-family: Arial; font-size: 15px; font-style: normal; font-variant: normal; font-weight: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></span></b>
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Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com3tag:blogger.com,1999:blog-4172796532462375810.post-18970725994903099112013-05-01T09:54:00.001-07:002013-05-07T07:07:22.972-07:00Hey, a trailer with "my" dinosaurs<div dir="ltr" style="text-align: left;" trbidi="on">
I know, it's not exactly an earth-shaking post on anatomy or reconstructing prehistoric life, but as I mop up some of the duties that have taken me away from blogging the last few months I thought I'd share this trailer, which shows off some of what took time away from blogging last year at this time:<br />
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<iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.youtube.com/embed/P7lBKBxIwGM?feature=player_embedded' frameborder='0'></iframe></div>
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I know that some will object to the anthropomorphization of the dinosaurs' actions, but actually a <i>ton of time</i> was spent on trying to develop less mammalian behaviors and expressions that would still read to an audience. In the end not all of them worked out, but the realities of such a project are that no movies with this sort of budget will get made if they people fronting the cash think audiences won't be able to relate to it.<br />
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Anyhow, I think the anatomy will be some of the best ever seen on the silver screen. The compositing and color in one or two of the shots don't look as good as say the Jurassic Park movies, but with a final release not coming until holidays in 2013 I seriously doubt the entire film has been through final color grading, so I wouldn't let that bother you.<br />
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What do you guys think?<br />
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P.S. I was only one of the anatomy designers - <a href="http://www.markwitton.com/" target="_blank">Mark Witton</a> was the other major designer that I know of (that is, created anatomical creature design illustrations as well as consulted), although there was an impressive assortment other paleontologists consulting on the project. After the 2D design was done the talented <a href="http://www.davidkrentz.com/davidkrentz/David_Krentz.html" target="_blank">David Krentz</a> added greatly to the character designs while transferring our work into the realm of three dimensions. Even after models are made a project like this depends on an army of incredibly talented artists, including those who paint the models, the technical directors and riggers who make it so those static models can move, and the animators who bring them to life. The finished look also strongly depends on the texture and render artists, including shader development, digital lighting, and the people who composite and color grade the finished imagery. I only use the term "my" to illustrate enthusiasm for having played a role, not to imply that the role was more than a cog in a large and very talented army of people who worked on the project.<br />
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Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com12tag:blogger.com,1999:blog-4172796532462375810.post-36648125468359172682013-04-01T09:05:00.001-07:002013-04-22T11:58:59.774-07:00Massive changes incoming to diplodocid sauropod stance<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://3.bp.blogspot.com/-EQG-X17fHJg/UVmuPtGqjnI/AAAAAAAASOk/kgGLwRSSlL8/s1600/apatosaurus+louisae+updated+April+2013.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="252" src="http://3.bp.blogspot.com/-EQG-X17fHJg/UVmuPtGqjnI/AAAAAAAASOk/kgGLwRSSlL8/s640/apatosaurus+louisae+updated+April+2013.jpg" width="640" /></a></div>
I know it's been a while since I posted anything, and luckily I have a backlog of content to share in the coming weeks, but I'm so excited about this project that I felt I had to post this, if for no other reason than as a warning to artists out there that are thinking about restoring sauropods in the near future.<br />
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<a name='more'></a>In particular diplodocoids - think "<a href="http://en.wikipedia.org/wiki/Therizinosaur" target="_blank">therizinosaur</a>" and you'll be on the right track. I can't say too much until the paper clears embargo later this week, but all of the oddities we see in diplodocoids will make a lot more sense, including the massive upcurve in the tail. It also nicely links <a href="http://www.app.pan.pl/archive/published/app54/app54-213.pdf" target="_blank">Taylor et al's</a> work on neck posture with Emily Giffin's older work on reduced forelimb innervation in <i>Apatosaurus</i>.<br />
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More as soon as the journal will allow it!<br />
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Edit: Well it's April 2nd, and I'm going to have a post on this prank up in the next day or two, but in case you are landing on this page from an external source I wanted to clarify that it was indeed an April Fool's prank.<br />
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Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com5tag:blogger.com,1999:blog-4172796532462375810.post-20660533673328497822012-10-25T12:22:00.003-07:002012-10-25T12:33:32.889-07:00Ornithomimus had wings...as an adult<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://i.livescience.com/images/i/32637/original/dino-art-121015.jpeg?1351185121" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="320" src="http://i.livescience.com/images/i/32637/original/dino-art-121015.jpeg?1351185121" width="280" /></a></div>
Just a quick note, because today we got one of the cooler new papers on dinosaurs to have been published in quite a while, describing not one but three specimens of <i>Ornithomimu</i>s with feathers.<br />
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And not only are there three specimens, but they are of different ages, and it turns out the feathers change as <i>Ornithimimus</i> grows up. In particular, the adults seem to have large wings with branching feathers on them, while the juveniles are covered only with the dinofuzz that we have become familiar with in the Chinese dinosaurs we have come to know and love.<br />
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This also pulls protowings further down the family tree - prior to this we only had definite wings in those wacky oviraptorids, deinonychosaurs (the various "raptor" dinosaurs), and those critters on the main bird line.<br />
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<a name='more'></a>So for those of you who illustrate the fleet-footed ornithomimids, you may need to alter some of the images. It also brings up some interesting questions regarding what the feather condition is in alverasaurs (which may have been ant-eaters) and the <a href="http://skeletaldrawing.blogspot.com/2011/11/falcarius-bizarre-sickle-cutter.html" target="_blank">bizarre therizinosaurs</a>. Specimens of the basal therizinosaur <i>Beipiaosaurus</i> have been found covered in dinofuzz and non-branching plumes, but not with true branching feathers, so it was assumed that the origin of wing-like structures must have happened closer to birds. Now it appears that was wrong, and we will have to try and figure out whether therizinosaurs lost them at some point during their evolution, or if perhaps the <i>Beipiaosaurus</i> specimen might have been too young to have developed them.<br />
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<a href="http://1.bp.blogspot.com/-Q6vSikk92TQ/UImPFjzIZTI/AAAAAAAAPkg/0K_9KUMO8bA/s1600/feathered+cladogram.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="263" src="http://1.bp.blogspot.com/-Q6vSikk92TQ/UImPFjzIZTI/AAAAAAAAPkg/0K_9KUMO8bA/s320/feathered+cladogram.jpg" width="320" /></a></div>
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There will also be questions about what those feathers were doing in such animals, which clearly did not fly or live in trees (and equally clearly did not evolve from flying or tree-dwelling ancestors); alas that will have to be another post. In the mean time, there are a couple other fun implications to consider from this paper:<br />
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1) The <i>Ornithomimus</i> specimens are from fluvial deposits; for those non-geologists out there all you need to know is that most dinosaur deposits around the world are fluvial, so this discover means we will have a lot more museums taking a closer look at their specimens, rather than assuming that feathers can't be preserve outside of a few special depositional settings. In other words, there are going to be a lot more discoveries in the coming years now that more people know what to look for.<br />
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2) Along those lines, not all of the feathered dinosaurs are from China anymore. Having been to China and seen many of the specimens personally this never was a big deal to me, but for the couple of stragglers that simply didn't want to believe in feathered dinosaurs, this should end any sort of conspiracy theory.<br />
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3) Looking at the already-decided debate about whether birds are dinosaurs, I can't really say that this is the final nail in the coffin - realistically all of the nails were pounded into that coffin years ago. But this discovery makes sure there is a large concrete memorial placed on top of the coffin preventing it from ever being dug up again, and for those of you who lived through the original birds are dinosaurs wars that has to be comforting.<br />
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If you have any thoughts or questions be sure to leave them below. And for the paleoartists out there, go forth and illustrated winged adult ornithomimids. Here is a skeletal to get you started:<br />
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<a href="http://2.bp.blogspot.com/-YOs5MskS_SA/UImT_LPRusI/AAAAAAAAPk8/IzjAdui9H_k/s1600/struthiomimus.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="324" src="http://2.bp.blogspot.com/-YOs5MskS_SA/UImT_LPRusI/AAAAAAAAPk8/IzjAdui9H_k/s640/struthiomimus.jpg" width="640" /></a></div>
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<span style="background-color: white; color: #231f20; font-family: Georgia, 'Times New Roman', serif; font-size: 13px; line-height: 20.78333282470703px;">Zelenitsky, D., Therrien, F., Erickson, G., DeBuhr, C., Kobayashi, Y., Eberth, D., Hadfield, F. 2012. Feathered non-avian dinosaurs from North American provide insight into wing origins. </span><a href="http://www.sciencemag.org/content/338/6106/510" target="_blank"><em style="background-color: white; color: #231f20; font-family: Georgia, 'Times New Roman', serif; font-size: 13px; line-height: 20.78333282470703px; margin: 0px; padding: 0px;">Science</em><span style="background-color: white; color: #231f20; font-family: Georgia, 'Times New Roman', serif; font-size: 13px; line-height: 20.78333282470703px;">. 338, 510-514</span></a><br />
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Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com9tag:blogger.com,1999:blog-4172796532462375810.post-37740577654032227522012-06-25T08:06:00.000-07:002012-06-25T11:12:13.234-07:00Terrible Claw!<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://2.bp.blogspot.com/-YrzqMXdJX8I/T-h-anKOEoI/AAAAAAAALnY/o_MTDI7Rbak/s1600/Deinonychus+skeletal.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="238" src="http://2.bp.blogspot.com/-YrzqMXdJX8I/T-h-anKOEoI/AAAAAAAALnY/o_MTDI7Rbak/s640/Deinonychus+skeletal.png" width="640" /></a></div>
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I haven't been posting much lately, so I thought I'd at least put up this skeletal I finished over the weekend...<br />
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It's <i><a href="http://en.wikipedia.org/wiki/Deinonychus" target="_blank">Deinonychus antirrhopus</a></i>, the quintessential "bird-like" dinosaur that John Ostrom discovered in the 1960s. More than any other discovery. it is responsible for sparking the <a href="http://en.wikipedia.org/wiki/Dinosaur_renaissance" target="_blank">Dinosaur Renaissance</a> of the 1960s and '70s. Bob Bakker's illustration of <i>Deinonychus</i> for Ostrom's monograph is probably the single most famous piece of paleo art ever produced (although it looks awfully cold in its featherless nudity!).<br />
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<a href="http://taggart.glg.msu.edu/isb200/dino13.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="149" src="http://taggart.glg.msu.edu/isb200/dino13.jpg" width="320" /></a></div>
<i>Deinonychus</i> was my favorite dinosaur for a lengthy portion of my childhood, so it was a lot of fun working on this skeletal - the closest thing that technical illustration has to a stroll down memory lane (for me at least).<br />
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There are a couple of unpublished specimens floating around, but this skeletal is based almost entirely on the <a href="http://peabody.yale.edu/" target="_blank">Yale Peabody Museum</a> and <a href="http://www.amnh.org/" target="_blank">AMNH</a> specimens that compromised Ostrom's original papers. Happily there is enough overlap that I don't anticipate any large changes.<br />
<span style="background-color: white;"><br /></span><br />
The two biggest questions I see are how retroverted the pubis is - I did not restore the pelvis with the more extreme <i>Velociraptor</i>-like backsweep seen in some reconstructions, but until an articulated pelvis is published we won't know the exact angle. Also, I'm not entirely sure whether the curve on the ventral margin of the jugal of YPM 5210 is natural, or due to being a bit squished.<span style="background-color: white;"><br /></span><br />
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Hopefully new specimens will clear those points up soon. The good news is those are fairly minor changes to make if necessary. In the mean time, I'm off to work on more skeletals, as well as preparing for my upcoming course on <a href="http://skeletaldrawing.blogspot.com/2012/06/im-teaching-online-course-on-anatomy.html" style="background-color: white;" target="_blank">advanced creature design</a>, which is now officially <a href="http://www.visualarium.com/advanced-creature-anatomy-webinar/" style="background-color: white;" target="_blank">open to registration</a><span style="background-color: white;">.</span></div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com5tag:blogger.com,1999:blog-4172796532462375810.post-16778539613472444842012-06-18T06:41:00.002-07:002012-06-18T07:02:47.463-07:00I'm teaching an online course on anatomy<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://2.bp.blogspot.com/-zqKk9fIOf7w/T98o-jVnkRI/AAAAAAAAKMY/vXMkgxQ8EvY/s1600/advancedCreature-Anatomy-header.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="212" src="http://2.bp.blogspot.com/-zqKk9fIOf7w/T98o-jVnkRI/AAAAAAAAKMY/vXMkgxQ8EvY/s640/advancedCreature-Anatomy-header.jpg" width="640" /></a></div>
<br />
So it turns out I haven't vanished (and actually have a lot of new content to share) but I've been swamped working on several projects of late. One of them I'd like to share, for those of you who really like dinosaurs but actually have different job aspirations:<br />
<br />
I'll be teaching a course for <a href="http://www.visualarium.com/" target="_blank">Visualarium</a>, one of the leading educational resources for visual effects artists (and artists in training) that use <a href="http://www.pixologic.com/home.php" target="_blank">Pixologic ZBrush</a>. The class is Advanced Creature Anatomy, and rather than being on dinosaurs (although you'll see some of them!) it centers on learning enough comparative anatomy from living and extinct animals to develop your own mental toolkit of concepts you can apply when to design more plausible speculative anatomy for fictional creature design.<br />
<br />
I'll do my best to keep it fun, so if ZBrush and 3D art is your thing, I invite you to check it out; we'll be conducting a <a href="http://www.visualarium.com/advanced-creature-anatomy-with-scott-hartman-ryan-kingslien/#" target="_blank">free webinar</a> this Thursday so people can get a taste of what the course will be like.</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com12tag:blogger.com,1999:blog-4172796532462375810.post-72557440904174883712012-04-27T21:24:00.001-07:002012-04-27T22:34:12.207-07:00Yup, the OK Apatosaurus is freakin' huge!<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://4.bp.blogspot.com/-DbMIbkxehQ8/T5tlW7qvjBI/AAAAAAAAJY4/wnavW88t-lE/s1600/OK_Apato.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="184" src="http://4.bp.blogspot.com/-DbMIbkxehQ8/T5tlW7qvjBI/AAAAAAAAJY4/wnavW88t-lE/s640/OK_Apato.png" width="640" /></a></div>
How big did Apatosaurus get? Well, that gray silhouette that is being dwarfed in terms of bulk there is <i>Supersaurus vivianae</i>. So yeah, that's one big honk'in sauropod...<br />
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The genesis of this post comes courtesy of a <a href="http://svpow.com/2012/04/25/the-giant-oklahoma-apatosaurus-omnh-1670/" target="_blank">Matt Wedel post</a> over at the excellent SV-POW! blog, where he was taking a look at the size of the partial Apatosaurus specimen preserved in Oklahoma, specimen OMNH 1670. Matt took a measuring tape to the OMNH specimen himself, and it measures up at a whopping 135 cm (for those of you who don't know the metric system, 135 centimeters is equal to one really big vertebra...).<br />
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But Matt really caught my attention when he stated:<br />
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<blockquote class="tr_bq">
<i>...so the big Oklahoma Apatosaurus was probably in Supersaurus territory, mass-wise, and may have rivaled some of the big titanosaurs.</i></blockquote>
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="http://www.skeletaldrawing.com/sauropods/me_carving_small.png" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="http://www.skeletaldrawing.com/sauropods/me_carving_small.png" width="247" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A younger me carving a pedal ungal. Look at<br />
that hair - what a hippy!</td></tr>
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<i>Supersaurus</i> is an animal near and dear to my heart - it's an animal I've literally shed blood over. Yes really. In addition to working with my coauthors on a <a href="http://skeletaldrawing.com/supersaur_project/CLPV_II_Supersaurus.pdf" target="_blank">description of the second specimen of <i>Supersaurus</i></a> and a reassessment of diplodocid phylogeny, we also had to produce a full mount of the animal under exceedingly tight time constraints. As with many small museums this meant we all had to pitch in, and that included learning how to sculpt missing bones. Near the very end of the project, while getting by on little more than 2 hours of sleep and coffee doses that would kill a small horse, I had a very small boo-boo with a carving knife (see photographic evidence at right). No stitches were necessary, and thankfully no sauropods where injured in the process.</div>
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The end result of our work was a mount that received top billing in a temporary exhibit in Japan in summer 2006. While the estimated length of 34 meters and mass estimate of 36-40 tonnes is smaller than some of the more sensational numbers that have been floated in popular books (and of course <a href="http://www.enchantedlearning.com/subjects/dinosaurs/dinos/Seismosaurus.shtml" target="_blank">the internet</a>), we suggested in our paper that many of those estimates were, shall we say... extravagant. <i>Supersaurus</i> appears to be close to the longest animal whose length can be reliably estimated (read: not counting <i>Amphiceolias fragilimus</i>), though it was lighter than the giant titanosaurs.</div>
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Given my personal stake here I wasn't about to take Matt's vicious maligning of <i>Supersaurus</i> on faith. But - and this is the darnedest thing about science - the facts are on his side. After scaling the fourth dorsal of <i>Apatosaurus louisae</i> up to the appropriate size, it turns out that the thing definitely is bulkier than <i>Supersaurus.</i> And if you try it with the other species of <i>Apatosaurus</i> (to whit: <i>A. ajax </i>and <i>A. excelsus</i>), it turns out just as bad - or worse in the case of <i>A. ajax</i>, who seems to have a proportionately shorter D4, which in turn leads to a larger animal when it's scaled to 135 cm.</div>
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<br /></div>
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Of course <i>Supersaurus </i>still looks to be longer by a fair amount, in large part due to the highly elongate neck. But when it comes to moving the dial on a scale, it's clear that Apatosaurus is just more sauropod than <i>Supersaurus</i>. Oh well <a href="http://www.skeletaldrawing.com/sauropods/supersaurus.htm" target="_blank">Jimbo</a>, we'll always have Japan...</div>
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<a href="http://www.skeletaldrawing.com/sauropods/japan.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="424" src="http://www.skeletaldrawing.com/sauropods/japan.png" width="640" /></a></div>
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</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com13tag:blogger.com,1999:blog-4172796532462375810.post-75360218019867099602012-04-08T21:40:00.001-07:002012-04-10T10:04:23.370-07:00Fishing at Dawn<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://3.bp.blogspot.com/-ZAP6u-0nF90/T4RoCX5GbBI/AAAAAAAAI54/chftuKB_wUo/s1600/Unenlagia_fishing_at_dawn_web.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="384" src="http://3.bp.blogspot.com/-ZAP6u-0nF90/T4RoCX5GbBI/AAAAAAAAI54/chftuKB_wUo/s640/Unenlagia_fishing_at_dawn_web.jpg" width="640" /></a></div>
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<i>Unenlagia comahuensis</i> looking for fish at dawn.<br />
<br />
<a name='more'></a>What can I say, it's been over a year since I tried my hand at something more artistic than a muscle or skeletal reconstruction. I did the sketch over a year ago, and had it ready to go (it's a digital painting in Photoshop), so I decided to give it a crack and it fell into place a lot faster than I'd expected (most of the time was spent painting water detail).<br />
<br />
I've reconstructed <i><a href="http://en.wikipedia.org/wiki/Unenlagia" target="_blank">Unenlagia</a></i> as somewhat less ecologically specialized than it's relatives <i>Buitreraptor</i> and <i>Austroraptor</i>, but fishing none-the-less. I don't really have a lot more to say about it - we'll get back to more hard core skeletal stuff soon, I promise! If you have any questions about the process I used I'll do my best to answer in the comments section.</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com13tag:blogger.com,1999:blog-4172796532462375810.post-34985681423734723972012-04-05T20:24:00.003-07:002012-04-05T20:24:57.433-07:00I.O.Yutyrannus<div dir="ltr" style="text-align: left;" trbidi="on">
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Hey, it's not every day that a completely fuzzy, nearly 30-foot long meat-eating dinosaur is described, now is it? I'm afraid my current schedule won't allow for a full skeletal of this critter for several more weeks, so consider the skull a down payment.<br />
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First, I should say that I'm not going to retread much of the excellent writing that has already been done on <i><a href="http://en.wikipedia.org/wiki/Yutyrannus" target="_blank">Yutyrannus</a></i>. If you'd like more in depth coverage, I highly recommend <a href="http://archosaurmusings.wordpress.com/2012/04/04/the-giant-feathered-tyrannosaur-yutyrannus-huali/" target="_blank">David Hone's excellent</a> write-up on his blog Archosaur Musings. For more coverage and some reasons to question whether <i>Yutyrannus</i> is a actually a tyrannosauroid, check out <a href="http://blogs.scientificamerican.com/tetrapod-zoology/2012/04/04/giant-feathered-tyrannosaurs/" target="_blank">Darren Naish's coverage</a> on his Scientific American TetZoo blog. I'd also be remiss to not mention <a href="http://blogs.smithsonianmag.com/dinosaur/2012/04/yutyrannus-the-most-cuddly-dinosaur-ever/" target="_blank">Brian Switek's article</a> over at the Smithsonian website.<br />
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<tr><td style="text-align: center;"><a href="http://farm4.staticflickr.com/3166/5856504670_71b6fb118c_o.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="213" src="http://farm4.staticflickr.com/3166/5856504670_71b6fb118c_o.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Photograph by <span style="font-family: inherit;"><span style="background-color: #fefefe; font-size: 12px; line-height: 15px; text-align: left;"><a href="http://www.flickr.com/photos/oggiscienza/5856504670/" target="_blank">Roberto Appiani </a></span> </span> </td></tr>
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What I will cover are some of the difficulties I've already observed in restoring <i>Yutyrannus</i>. The reconstruction above is based on one of the beautifully preserved skulls (there are 3!); like everything else found in the <a href="http://en.wikipedia.org/wiki/Yixian_Formation" target="_blank">Yixian Formation</a>, the specimens have been squashed flat. Relatively robust bones like a femur hold up fairly well, but skulls really don't. They tend to be highly three-dimensional in shape, and are made out of relatively thin elements. In particular, on theropod skulls the top and rear of the skull tend to fold upward as the head undergoes the pancake treatment of <a href="http://en.wikipedia.org/wiki/Diagenesis" target="_blank">diagenesis</a>.<br />
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Small dinosaurs with larger eyes and brains (like the juvenile <i><a href="http://en.wikipedia.org/wiki/Scipionyx" target="_blank">Scipionyx</a></i> above seen at right) exaggerate the problem even more, and unsuspecting artists can restore the skulls as having huge domes over the eyes if they don't know better. In Yutyrannus I suspect we are seeing something similar, which probably exaggerates the apparent size of the nasals (especially as you move closer to the eyes), as well as the top of the skull at the back.<br />
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If you check out the <a href="http://archosaurmusings.files.wordpress.com/2012/04/yutyrannus_skull.jpg" target="_blank">beautiful photograph</a> of the head of juvenile specimen ELDM V1001 in David Hone's blog (the same one I've restored above), you can probably see what I'm getting at.<br />
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<a href="http://1.bp.blogspot.com/-sOCxR8LAxpo/T35g2Yd6o8I/AAAAAAAAIJw/GInnd5UH_YE/s1600/Yutyrannus+head+comparison.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="320" src="http://1.bp.blogspot.com/-sOCxR8LAxpo/T35g2Yd6o8I/AAAAAAAAIJw/GInnd5UH_YE/s320/Yutyrannus+head+comparison.jpg" width="188" /></a>The skull restoration at the beginning of this article takes those things into account, attempting to return a 3-dimensional shape to the steam-rolled remains of the skull (by the way, the mandible is largely a place holder for now, the surangular is actually a fairly different shape). Below I've included a comparison of the the skull with and without those "corrections". Because there are three skulls, and because they have likely been subject to distortion from somewhat different angles, I should be able to double check this with greater precision once I get around to doing the full skeletal.<br />
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For those of you investing the time to study the comparison image, the top one is the restored version, while the bottom one treats the outline more literally. In both cases I've re-articulated the lacrimal (the bone in front of the eye) with the jugal (the bone underneath the orbit). In both cases the lower jaw is (as mentioned above) just a generic placeholder that is the correct size, but doesn't take the information from other specimens into account.<br />
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That's all the time I have to put into a new skeletal on my own whim for the moment. Until I get a chance to do the whole thing enjoy this <i>Yutyrannus</i> I.O.U.<br />
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</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com8tag:blogger.com,1999:blog-4172796532462375810.post-4211156829253201142012-04-03T11:16:00.001-07:002012-04-03T21:17:40.306-07:00When journalists attack!<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://1.bp.blogspot.com/-FMBoMYVVIPI/T3sQ8djhT2I/AAAAAAAAIIQ/kdkfOTO9Bzk/s1600/Bully-for-brontosaurus.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="318" src="http://1.bp.blogspot.com/-FMBoMYVVIPI/T3sQ8djhT2I/AAAAAAAAIIQ/kdkfOTO9Bzk/s320/Bully-for-brontosaurus.jpg" width="320" /></a></div>
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As recently <a href="http://www.dailymail.co.uk/sciencetech/article-2124420/Dinosaurs-DIDNT-rule-earth-The-huge-creatures-actually-lived-water--tails-swimming-aids.html" target="_blank">reported</a> on <a href="http://www.dailymail.co.uk/sciencetech/article-2124420/Dinosaurs-DIDNT-rule-earth-The-huge-creatures-actually-lived-water--tails-swimming-aids.html" target="_blank">several</a> <a href="http://www.ibtimes.co.uk/articles/323260/20120403/dinosaurs-lived-underwater-researchers.htm" target="_blank">apparently</a> legitimate news sources, a new interpretation of dinosaur biology has been proposed that is "<i>so revolutionary it stands the whole world of palaeontology on its head.</i>" What is this landmark new idea that has set paleontologists agog? It's being termed the "Aquatic Dinosaur" hypothesis, and as the name implies it<span style="background-color: white; color: #282828; font-family: arial, helvetica, sans-serif; font-size: 14px; line-height: 20px; text-align: -webkit-auto;"> </span>suggests that the Charles Knight painting you see above isn't out of date, it was just ahead of its time. And not just for sauropods, but <i>all</i> large dinosaurs.<br />
<br />
If something smells fishy to you, it's not just the swamp water; something is very wrong here...<br />
<br />
<a name='more'></a>First, to be clear, there is no such controversy, or even an idea that you need to take seriously. To be sure, some guy wrote an article in <a href="http://www.labnews.co.uk/digital-editions/" target="_blank">Laboratory News</a>, so I've listed the evidence below in a handy tabulated format:<br />
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<li><br /></li>
<li><br /></li>
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Literally, no data was provided in the article. The author makes references to "calculations" that were run, but they never make it into print. The article is mostly long-winded hyperbole, filled with such gems as "Dinosaurs look more convincing in water, and the physics stands up more soundly."<br />
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So the author's main point appears to be "See??! They look better in the water, so it must be true! Also, I have some secret calculations I won't bother to share with you support my aesthetic preference!" The fact that it was in the April edition might give us pause to wonder if this isn't a big joke, but alas there are reasons to suspect otherwise (see below).<br />
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Two general claims seem to permeate the article, that dinosaurs were just <i>really big</i> so water would help, and that dinosaur footprints aren't as deep as you'd expect from such big animals. Of course how deep a footprint sinks is only partially related to the mass of an animal. The surface area of the foot must be taken into account, as smaller feet concentrate the weight while large feet spread it out. That's why a woman in high heels can dent substrates that elephants won't. And of course the substrate itself matters - no animals leave tracks on concrete, while people easily get bogged down in viscous mud.<br />
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The "they're just so big" meme, is painfully wrong; there's an entire literature of biomechanics that shows that dinosaur limbs are strong enough to support terrestrial locomotion. And of course dinosaurs lack the aquatic features seen in animals such as hippos or crocodiles, which actually spend most of their time in water. Running your mouth off (err, running your text editor off?) without even bothering to read the literature is one of those "the stupid, it hurts!" sorts of moments.<br />
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<tr><td style="text-align: center;"><a href="http://www.skepticfriends.org/forum/uploaded/1897/SIWOTI.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="http://www.skepticfriends.org/forum/uploaded/1897/SIWOTI.jpg" width="291" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">From <a href="http://xkcd.com/386/" target="_blank">xkcd</a></td></tr>
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Ok, enough ragging on "professor" <a href="http://www.labnews.co.uk/news/prehistoric-revolution/" target="_blank">Ford</a>; he's either a crank or a practical joker (perhaps those aren't mutually exclusive?), but he's not the first person to have a loony idea and not support it with any evidence. Heck, the internet is littered with such people.<br />
<br />
The real problem here is that his personal speculation somehow got reported as news by the mainstream press. First, if this isn't an April Fools prank, it calls the editorial judgement of Laboratory News into serious question (and if it IS somehow a prank, why was it allowed to be spread pre- and post-April 1st to other media outlets?). Amusingly, on page 17 of the same issue of Laboratory News there is an article lamenting the state of science reporting in the news (seriously, I couldn't make this stuff up if I tried).<br />
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If you or your lab has a subscriptions to Lab News, I'd seriously consider making inquiries, or simply dropping it. If they allow this sort of thing to happen, how can you trust the rest of their articles?<br />
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More importantly, why on Earth was this story picked up and repeated by serious news outlets? Does <a href="http://news.bbc.co.uk/today/hi/today/newsid_9710000/9710630.stm" target="_blank">BBC Radio 4</a> do any sort of review at all before they put someone on the air? Have journalistic standards sunk that low at the British Broadcasting Company? A quick listen to <a href="http://news.bbc.co.uk/today/hi/today/newsid_9710000/9710630.stm" target="_blank">the audio</a> shows the show starting out as mildly skeptical, but concluding by comparing Ford to Galileo freakin' Galilei!<br />
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<b>W. T. F.?!!</b><br />
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<a href="http://en.wikipedia.org/wiki/Galileo_Galilei" target="_blank">Galileo</a>, you may recall, did actual science and was being silenced by non-scientists due to the (presumed) theological implications of his findings. Mr. Ford (who the BBC charitably refers to as a "cell biologist" despite being more of a media gadfly and author of popular books and articles, not a publishing scientist) is not doing science - he in fact seems intent on ignoring science at all costs - and was simply being refuted by an actual, you know, paleontologist. Yet they whipped out the Galileo reference!<br />
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<a href="http://4.bp.blogspot.com/-kIp-RvDrVgY/T3s9zSwsOJI/AAAAAAAAIIY/7GTxPnDsd94/s1600/galileo-WTF.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="200" src="http://4.bp.blogspot.com/-kIp-RvDrVgY/T3s9zSwsOJI/AAAAAAAAIIY/7GTxPnDsd94/s200/galileo-WTF.jpg" width="188" /></a>Which honestly begs the question of whether anyone should bother listening to BBC Radio 4. To be fair, <a href="http://news.bbc.co.uk/today/hi/today/newsid_9405000/9405448.stm" target="_blank">actual paleontology</a> has been covered on Radio 4 and it seems to otherwise have solid programming, but the BBC should move swiftly to clear this up if they don't want a permanent stain on their credibility.<br />
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Most of the web and print articles are based on the BBC interview, but that doesn't exonerate them; not a single one of them bothered to inquire as to whether there was any real science here, and when they did contact paleontologists, they presented it as another "side" in a debate, rather than the debunking of junk Science.<br />
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Regular readers have already seen that sources like Scientific American can get even basic anatomical facts <a href="http://skeletaldrawing.blogspot.com/2011/09/um-hey-scientific-american-bird-knees.html" target="_blank">wrong</a>, but this goes well beyond an incorrect fact in an otherwise solid story; it's misleading through and through. In a follow up article the Telegraph <a href="http://www.telegraph.co.uk/science/dinosaurs/9182732/Weird-and-wonderful-dinosaur-theories-of-recent-times.html" target="_blank">directly compares</a> the aquatic dinosaur nonsense with actual research, in the process repeatedly mutilating the concept of a <a href="http://en.wikipedia.org/wiki/Scientific_theory" target="_blank">scientific theory</a>.<br />
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This stuff really matters. We live in a world where <a href="http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0040167" target="_blank">huge swaths of people</a> don't understand basic scientific concepts, and this sort of nonsense just makes it harder to teach. Worse, listeners that were sympathetic to the reporting will become disillusioned when they find out the reality of the situation, possibly making them view all science more cynically (or simply avoiding science altogether).<br />
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We deserve better science reporting than this. The BBC and everyone else who carried this story should be ashamed.<br />
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Note on the possibility of an April Fools prank:<br />
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<a href="http://1.bp.blogspot.com/-9YxDE8W9NDU/T3tGYKKpOWI/AAAAAAAAIIg/HLaprmvJLEA/s1600/cute_kitten.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="150" src="http://1.bp.blogspot.com/-9YxDE8W9NDU/T3tGYKKpOWI/AAAAAAAAIIg/HLaprmvJLEA/s200/cute_kitten.jpg" width="200" /></a>Several people (<a href="http://svpow.com/2012/04/03/did-sauropds-support-their-weight-by-living-in-vast-shallow-lakes/#comment-16418" target="_blank">myself included</a>) have raised the question of whether this could be an elaborate prank. While I sincerely hope so, it turns out that Mr. Ford has a history of publishing similarly speculative and unfounded ideas, including an idea a <a href="http://viewer.zmags.co.uk/publication/dd66a27c#/dd66a27c/24" target="_blank">previous article</a> in Laboratory News on human and canid evolution. The continued media promotion of the aquatic dinosaur story after April 1st, and a somewhat disturbing "how to spring rhetorical questions on paleontologists" guide on <a href="http://www.brianjford.com/w-dino01.htm" target="_blank">Ford's website</a> cast significant aspersion on the possibility of this being a joke.<br />
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It's worth noting, however, that the above criticisms of science reporting in the media do not change even if it is a prank, as the news media has clearly been duped one way or another, and could easily have discovered it with a modicum of research prior to reporting it.</div>
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</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com9tag:blogger.com,1999:blog-4172796532462375810.post-70825100625987221042012-03-29T09:03:00.001-07:002012-03-29T09:03:15.803-07:00Carnotaurus - delving into self-parody?<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://2.bp.blogspot.com/-mWCYzRbaCHs/T3R9p0CbcPI/AAAAAAAAICE/CDtOr0Z5vgY/s1600/carnotaurus.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="246" src="http://2.bp.blogspot.com/-mWCYzRbaCHs/T3R9p0CbcPI/AAAAAAAAICE/CDtOr0Z5vgY/s640/carnotaurus.png" width="640" /></a></div>
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This is <i><a href="http://en.wikipedia.org/wiki/Carnotaurus" target="_blank">Carnotaurus sastrei</a></i>, a theropod that seems to be little more than a mouth with a set of legs to carry it around. <i>Carnotaurus</i> belongs to an aberrant group of theropods called <a href="http://en.wikipedia.org/wiki/Abelisaur" target="_blank">abelisaurs</a>, which dominated much of the southern hemisphere during the Cretaceous. While all abelisaurs appear odd to our <a href="http://en.wikipedia.org/wiki/Tetanurae" target="_blank">tetanuran</a>-biased eyes, it seems like <i>Carnotaurus</i> is striving for weirdness as a means to its own end; as if it were making some sort of meta-commentary on abelisaur diversity.</div>
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I should take a moment to make a public service announcement: I apologize for my absence from blogging and other social media that last several weeks - I've been producing more than a few new skeletals (on a schedule), so time has become a scarce resource. On the upshot, several of the new skeletals address blog-worthy topics, so I'm going to produce some shorter posts that examine them.</div>
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One of the questions raised in the comments of a previous post involved the hyoid bones - the bones that support several muscles, including in dinosaurs the tongue musculature. Being long, slender bones that don't directly articulate to other bones, hyoids are often not found (and other times are probably not collected or m-identified). Even when they are found, their lack of a direct connection to other bones makes restoring them problematic. In <i>Carnotaurus</i> this wasn't a problem, as they were found in direct association with the underside of the mandible, apparently in their life position. The fact that extensive skin impressions were found with <i>Carnotaurus</i> reinforces the likelihood that the soft tissue holding the hyoid in place had not been disturbed.</div>
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In the skeletal above you can see part of the hyoid sticking out from under the bottom-rear part of the jaw. Part of the hyoid is obscured, but there's not much I can do about that. Having the hyoid is actually pretty useful - the trachea and esophagus have to pass through it (or above it), so having a properly positioned hyoid constrains the throat tissue. </div>
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<i>Carnotaurus</i> is also striking due to its advanced arm reduction - in side view the arms almost disappear, as they don't even extend past the stomach. What on Earth could such arms be used for? Hold on to that thought, as I'm not ready to go public with my thoughts on that just yet. But it sure reinforces the "legs carrying a head" image.</div>
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Finally, for those of you paleo-artists out there considering <i>Carnotaurus</i> as your next paleo-subject, I wanted to point out something not obvious in side view: <i>Carnotaurus</i> is really flat on top. The transverse processes on the tail actually stick up in a V-shape that reaches just about to the level of the neural spine. Persons & Currie <a href="http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0025763" target="_blank">recently described</a> how this impacts the tail muscles (TL;DR version is the tail is very wide at the base, and quite flat on top).</div>
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<tr><td class="tr-caption" style="text-align: center;">From <a href="http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0025763.g003&representation=PNG_M" target="_blank">Person's & Currie</a></td></tr>
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The back and neck also have osteological structures that raise up to, or above the level of the neural spine. So most of the animal should be restored as having a remarkably flat top. Given how narrow the head is, this must have produced a really strange life appearance. </div>
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A final note on the skeletal itself: while Carnotaurus is a wonderfully complete specimen, the lower legs and much of the tail is missing, so those elements were restored after its close cousin <i>Aucasaurus</i>.</div>
</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com5tag:blogger.com,1999:blog-4172796532462375810.post-30482694175379801162012-01-28T19:10:00.000-08:002012-01-28T19:10:07.735-08:00The evolution of (my) Acrocanthosaurus<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://4.bp.blogspot.com/-cpbXJmthfDk/TxxL1tuvg-I/AAAAAAAAHcc/TprKj-AdvLI/s1600/acro_v_acro.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="296" src="http://4.bp.blogspot.com/-cpbXJmthfDk/TxxL1tuvg-I/AAAAAAAAHcc/TprKj-AdvLI/s640/acro_v_acro.png" width="640" /></a></div>
With <i><a href="http://skeletaldrawing.blogspot.com/2012/01/revisiting-fisher-king.html" target="_blank">Spinosaurus</a></i> temporarily out of the way, we're going to take a closer look at <i>Acrocanthosaurus</i>. This series is going to include a post on what we know and don't know about Acrocanthosaurus, how to restore the skeletal in multiple views, and how to restore the muscles. At the end of that series I'll also comment on some areas of soft-tissue variation that artists should keep in mind when they envision "their" <i>Acrocanthosaurus</i>.<br />
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First though, I wanted to take a moment to look at how my own reconstruction of <i>Acrocanthosaurus</i> has changed over the last decade. With any luck some of my earlier errors in methodology might help others who want to do skeletals. Also I hope to provide some insight to how I update skeletals over time, and the importance of revising your work as new data is published.<br />
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Join me after the break for an in depth look at the evolution of (my skeletal reconstruction) of <i>Acrocanthosaurus</i>...<br />
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<a name='more'></a>Although <i>Acrocanthosaurus</i> is hardly the best known theropod, it provides more than its share of challenges when attempting to reconstruct it. In my case, I attempted the original skeletals during what I'd call a methodological nexus - it was one of the first skeletals I attempted within an entirely digital environment, and to some degree the initial reconstruction suffered as a result. I had developed many techniques when I executed skeletals in pen and ink, and most of those translated fairly well during the years (roughly 2000-2004) when I used a hybrid method of digital and ink work. Alas, attempting to work entirely inside a computer forced me to rediscover how to accomplish the same things inside of <a href="http://www.amazon.com/mn/search/?_encoding=UTF8&x=0&tag=skeletaldrawi-20&linkCode=ur2&y=0&camp=1789&creative=390957&field-keywords=photoshop&url=search-alias%3Daps" target="_blank">Photoshop</a>, and as a result the first couple of attempts were actually a step backward in some ways. Luckily I stuck with it, and the results are now far better then anything I accomplished in the "analog" world.<br />
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<b><span style="font-size: large;">In the beginning...</span></b><br />
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<i><a href="http://en.wikipedia.org/wiki/Acrocanthosaurus" target="_blank">Acrocanthosaurus</a> </i>itself is not a new dinosaur. It was described in 1950, and it was noted at the time that the specimen was a carnosaur with enlarged neural spines on the back. What really brought <i>Acrocanthosaurus</i> to my attention, however, was the reconstruction of <a href="http://naturalsciences.org/" target="_blank">NCSM</a> 14345, the "Fran" specimen, which was prepared, molded, and mounted by <a href="http://www.bhigr.com/pages/info/info_acro.htm" target="_blank">Black Hills</a> in the 1990s. One of those specimens became part of a travelling display that I contributed to, and I was inspired by the fully restored mount, as well as my ability to take lots of photographs of the mount.<br />
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Alas, that was in the "olden days" when cameras captured light on sheets impregnated with silver nitrate rather than CCDs, and I never did scan in those photos. I still had them in 2003, but they appear to be one of many casualties of moving around frequently.<br />
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I was also attending the University of Wyoming, and their Geology library had supplied valuable gifts: descriptions of <i>Acrocanthosaurus</i> specimens by Jerry Harris (1998), and Currie & Carpenter (2000). Armed with proto-pdfs (read: xeroxed copies), lots of photos, and an abundance of enthusiasm I sat down to create my first all-digital skeletal reconstruction.<br />
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<b><span style="font-size: large;">The tomb of the unknown skeletal...</span></b><br />
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Directly above, what you <i>don't see </i>is my first <i>Acrocanthosaurus</i> skeletal. I'm not being shy, I just didn't back up the original very carefully, and eventually the hard drive it was on suffered a systemic failure. <a href="http://db.tt/MOCnMZO" target="_blank">Cloud storage</a> was a pie-in-the-sky dream at the time, so I've lost several "original" skeletal files during the course of computer failures over the years. Luckily I've been anal retentive enough to keep current versions of skeletal files on multiple hard drives, so I haven't totally lost a reconstruction (at least, not a digital one).<br />
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What I can say is that in many ways my first attempt was an unmitigated failure. For starters, I didn't actually have the papers I mentioned above in their entirety. I'd read them in Laramie, but at the end of the semester I only photocopied the parts I thought I'd need (hey, it took time and money to copy texts in those days!). And of course the photocopies didn't always do justice to the original figures.<br />
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<a href="http://i16.photobucket.com/albums/b18/Crazyharp81602/2010-05-17-facepalm-hi-res.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="206" src="http://i16.photobucket.com/albums/b18/Crazyharp81602/2010-05-17-facepalm-hi-res.jpg" width="320" /></a></div>
Instead I had to rely strongly on the photographs I had taken of the Fran mount. Even that was fraught with uncertainty, as I hadn't been able to take orthographic photos of the mount. Also, there were errors in the fully restored mount, but without all of the text from Currie & Carpenter I didn't always recall what was restored and what was cast from original bone. The results were predictably poor.<br />
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You don't have to take my word for it though. I posted that first attempt to the Dinosaur Mailing List in early July of 2003. <a href="http://dml.cmnh.org/2003Jul/msg00128.html" target="_blank">Jaimie Headden</a> and <a href="http://dml.cmnh.org/2003Jul/msg00152.html" target="_blank">Waylon Rowley</a> made quick and (deservedly) pointed replies. I had missed several characteristic parts of the tail and neck vertebrae, and a bunch of other minor details had simply been missed.<br />
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What happened? For one thing I really didn't have enough data on hand. But more importantly, I was distracted by having to solve the technical problems of a new medium. Digital skeletal reconstructions have many advantages, but at the time they were lost on me as I struggled to figure out how to simply do the things I'd taken for granted in the "analog world".<br />
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<b><span style="font-size: large;">The Acro strikes back</span></b><br />
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<a href="http://4.bp.blogspot.com/-mYrjiG93Wbs/TyR5JFFXMWI/AAAAAAAAHjA/fBlGasTy_Lo/s1600/Acro_deux.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="226" src="http://4.bp.blogspot.com/-mYrjiG93Wbs/TyR5JFFXMWI/AAAAAAAAHjA/fBlGasTy_Lo/s640/Acro_deux.png" width="640" /></a></div>
With a bit of work, I quickly produced the skeletal above, which addressed some of the basics. It wasn't a horrible attempt - it accurately captures almost all of the proportions, and many of the changes since have been either due to newer research getting published, or on changing interpretations in soft tissue reconstruction.<br />
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<a href="http://upload.wikimedia.org/wikipedia/commons/9/91/Acrocanthosaurus_skeleton_(1).jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="213" src="http://upload.wikimedia.org/wikipedia/commons/9/91/Acrocanthosaurus_skeleton_(1).jpg" width="320" /></a>One thing mistake in this earlier version is that the neural spines were too tall - I had based their height on the mount of the Fran specimen, but it turned out that neural spines were not complete in that specimen (at least not the ones in the back, sacrum, or the front part of the tail). A review of other specimens ruled out such a grandiose neural spine height, and that also has implications for paleoartists wondering how to illustrate the back.<br />
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Two important papers were published on <i>Acrocanthosaurus</i> after that early skeletal. One was on the forearm, which showed that the arm couldn't actually reach as far forward as I'd illustrated it (and also clarified details of the size and shape of all the elements). Another paper was published in the last year that updated our understanding of the skull of <i>Acrocanthosaurus</i>. When I was asked if I could supply the skeletal to an upcoming book, it was clear that I had to revamp the skeletal before sending it along...<br />
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<b><span style="font-size: large;">Back to the future</span></b><br />
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<a href="http://4.bp.blogspot.com/-Uf5GuTu4grs/TySyMW6ELcI/AAAAAAAAHjY/AkFy3YCkx5Q/s1600/Acro_3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="212" src="http://4.bp.blogspot.com/-Uf5GuTu4grs/TySyMW6ELcI/AAAAAAAAHjY/AkFy3YCkx5Q/s640/Acro_3.png" width="640" /></a></div>
Which brings us back to my current skeletal. In addition to the new skull and arm data, the newfangled Acrocanthosaur naturally sports my <a href="http://skeletaldrawing.blogspot.com/2012/01/great-skeletal-repose-of-2011_20.html" target="_blank">new skeletal pose</a>. So how crazy different is it? In some ways it's pretty similar - the overall dimensions really didn't change, and that's a good thing. A bunch of more subtle soft-tissue changes took place (at least some of which will get to star in their own post in the future), but a couple of obvious ones involve the tail and the neck.<br />
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The tail in the newer one has a heavier base, reflecting the research by Persons and Currie on tyrannosaur tails that I <a href="http://skeletaldrawing.blogspot.com/2011/03/t-rex-baby-got-back.html" target="_blank">wrote about</a> last year. The tail also is a bit less bouncy. The current skeletal is moving at a more sedate pace, and its tail is no longer bouncing along like a dropped garden hose. The neural spines on the tail have also been updated, with the spines on the front of the tail (near the hips) shorter to reflect other specimens, and the ones in the middle a bit taller, again based on other specimens.<br />
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Looking at the neck, the silhouette is no longer shrink-wrapped as tightly to the skeleton. I will probably address the "why" part of that in a later post, but suffice it to say that the newer Acro would have an easier time wolfing down large pieces of meat it tore off a carcass.<br />
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A final set of changes were made in the pectoral girdle (the shoulder region). I added a furcula which, while not found in <i>Acrocanthosaurus</i>, now appear to be a primitive feature found in all theropods. Additionally, I used to illustrate a large cartilaginous presternum that split the coracoids apart (you can see it poking out the bottom and front of the chest area on the older skeletal).<br />
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Reflecting the articulated chest regions of other non-maniraptoran theropods, I changed it to a smaller presternum, that would have ended sooner and allowed the coracoids to almost contact one another along the midline. This slightly changes the outline in side view, but in front or top view has the effect of narrowing the front of the torso across the shoulders. Now if only someone would produce multiple-angle skeletals of Acrocanthosaurus to show this off...<br />
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...tune in next week, for the exciting "surprise" reveal!</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com8tag:blogger.com,1999:blog-4172796532462375810.post-40026742408414509572012-01-24T09:53:00.000-08:002012-01-24T10:42:14.176-08:00Dawn Thief<div dir="ltr" style="text-align: left;" trbidi="on">
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A quick post (and a new skeletal) today, while I apply a bit more polish to the <i>Acrocanthosaurus</i> series. To satisfy all of your skeletal-drawing-based-amusement needs I give you <i><a href="http://en.wikipedia.org/wiki/Eoraptor" target="_blank">Eoraptor lunensis</a></i>, one of the most primitive dinosaurs yet discovered.<br />
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<a name='more'></a>How primitive? So primitive that we can't actually answer that question with any certainty right now. <i>Eoraptor</i> is one of those taxa that bounces around a lot in different studies. When it was originally describe, it was thought to be one of the most primitive theropods known. Other studies suggested it might be more primitive than the split between theropods and sauropods. Recently, some have even found it to be on the line leading to sauropods!<br />
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<a href="http://4.bp.blogspot.com/-Xz2XzrknuyY/Tx77eX1Q3TI/AAAAAAAAHf0/G6SvIt2sLkI/s1600/eoraptor_phylo_known_unknowns.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="588" src="http://4.bp.blogspot.com/-Xz2XzrknuyY/Tx77eX1Q3TI/AAAAAAAAHf0/G6SvIt2sLkI/s640/eoraptor_phylo_known_unknowns.png" width="640" /></a></div>
All three positions have shown up in recent studies, so for now at least the answer is "we're not sure". Why all the trouble figuring out who is <i>Eoraptor</i>'s closest relative? Basically what it boils down to is that Eoraptor is so primitive that this is what the common ancestor of theropods and sauropodomorphs would look like. No matter where <i>Eoraptor</i> ends up on the dinosaur family tree, the difference between it and animals at the other position will be very small indeed.<br />
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If you compare <i>Eoraptor</i> to <i>Panphagia </i>(which I examined in <a href="http://skeletaldrawing.blogspot.com/2011/06/skeletal-reconstructions-schematic-vs.html" target="_blank">this</a> post), which is a well-supported basal sauropodomorph, you can see just how similar the two are. The problem is sort of like being handed photographs of all of the Kennedy's when they were two years old and being asked which one was closest in age to JFK - there's a correct answer, but it's awfully hard to tell from the information you have. <br />
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As for the skeletal reconstruction, <i>Eoraptor</i> didn't present nearly as many challenges as some other taxa do. For one, it's know from <a href="http://www.projectexploration.org/eoraptor.htm" target="_blank">fairly complete remains</a>. It would have been nice to have a more detail description of the animal in print (the original papers leave something to be desired along those lines), but luckily the specimen is available in detailed orthographic photos, which do a nice job of supplementing the published data.<br />
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That's all for now!</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com4tag:blogger.com,1999:blog-4172796532462375810.post-10217601482282950902012-01-20T22:27:00.000-08:002012-01-21T12:07:26.922-08:00The Great Skeletal Repose of 2011: A Retrospective<div dir="ltr" style="text-align: left;" trbidi="on">
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Well, it's 2012, so the Great Skeletal Repose of 2011 must officially come to an end. Most of the bipedal skeletals in my collection have been reposed much like this <i>Velociraptor</i>. I had plenty of things to say, and we saw some great discussion by guest writers, but when it comes right down to it, the issue feels incomplete without some sort of summary as to how I got here, and what's left to do. So let's take a quick look at where things stand now...</div>
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<a name='more'></a>To some degree, the walking pose shown above was selected by acclimation. When I started to show off different types of poses, by far the most popular was the walking pose you see above. And I want this pose to be one that other scientific illustrators can feel free to adopt, so widespread can only enhance that proposition. But it wasn't just a popularity contest - there are several practical reasons why this walking pose became the winner:</div>
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<b>The Good</b></div>
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1) Utility - Greg Paul of course will continue to use his pose, and a number of previously published skeletals by other authors (including all of mine up until last year) had adopted the same pose. By selecting the walking pose the retracted left leg remains unchanged, allowing for a easy comparison of the proportions. This was probably the biggest factor.<br />
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2) Functional Aesthetics - The old pose of animals sprinting along at a lively clip tended to impose a specific hypothesis of activity on the animals. While in some cases dashing along may have been quite likely, it still required that a research who wanted to use the skeletals to swallow that hypothesis, whether they agreed with it or not. With Velociraptor that wasn't unlikely, but with larger theropods it became needlessly controversial, and with graviportal taxa like therizinosaurs the results could be laughable.<br />
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3) Laziness - I prefer "efficient" over "lazy", but no matter what label you place on it, this pose required a minimal amount of alteration to my existing skeletals. And the stark reality is that when you have to repose hundreds of technical illustrations that time adds up. Quickly. Of course this reason would not have been sufficient if it weren't for the more important points 1 & 2, but it sure was a nice bonus.</div>
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Does that mean I'm thrilled with the outcome?</div>
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Yes and no. Since I'm starting with a blank slate, it would have been fun to come up with something truly distinctive. Yet the allure of the new wasn't worth sacrificing how useful the skeletals were for comparative purposes. Also, thanks to lots (and lots) of time spent pondering the issue, and to the extra stimulus provided by Mike Habib and Jon Conway's excellent guest posts, I've come to some unsettling questions that are still unresolved.</div>
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<b>The Bad</b></div>
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1) Whither goest utility? - As I wrote way back in the halcyon days of...spring 2011, after I announced that I would relinquish the old pose and select a new one I got many requests that I refrain from this. Almost all of them were concerned with losing the ability to easily contrast my skeletals to others after the repose. I was (and am) sympathetic to that plight, and selected a pose that minimized the "damage". </div>
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Yet I also had a disconcerting realization: Both Greg Paul and myself had been varying the pose of the forelimbs for years and no one ever bothered to complain about the loss of utility. Sometimes we've both illustrated maniraptorans with the arms flexed into their folded-wing pose, sometimes not. Less advanced theropods obviously never adopted such a pose, so their arms often hang listlessly. My tyrannosaurs went from a similar "hanging out" pose to one that reflected the work done by Lipkin and Carpenter. Why was the issue never broached? Are forelimbs less important for comparative purposes than hind limbs? Or do we naturally gravitate towards the larger structure because of how our visual cortex's work? I don't know, but I'm unsatisfied by the discrepancy.</div>
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2) Is variety the spice of life? - Jon Conway also brought up a good point in his guest article, that there isn't a single pose that best serves every need. This is certainly true, and while I still feel that within groups making poses similar is useful, I also have to admit that in some ways the job has just begun.</div>
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3) That job has just begun - Oh yeah, and another thing. Turns out there are quadrupedal dinosaurs too. Who'd have thunk it, eh? Despite the obvious and objective superiority of theropods, prosauropods, and basal ornithiscians, there's still a lot of four-footed critters in my skeletal collection, and I'm going to have to come up with a pose for them as well. Two actually, since the graviportal species will need a pose that is different from the quadrupeds with flexed limbs. Ah well, that just means that 2012 will also need to have a Great Skeletal Repose as well.</div>
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<b>An end and a beginning</b></div>
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So we've come full circle. I've adopted a pose for the bipedal dinosaurs, but still have to come up with (two!) new poses for quadrupeds. I still am very much interested in soliciting outside opinions on the subject, but I also want the blog to move back to posts about anatomy and reconstruction, rather than a continuing series of posts on the technical issues behind selecting a pose. So expect to see the occasional progress report on the quadrupeds, but don't expect it to dominate space on the blog this year.</div>
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If you have a strong opinion on the subject, don't hesitate to email me (or use that Gchat thing). In the mean time, I really do have a series of upcoming posts on Acrocanthosaurus and Spinosaurus anatomy, as well as the trials and tribulations of reconstructing skeletals in multiple views.</div>
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Stick around, won't you? 2012 should be an interesting year.</div>
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<a href="http://1.bp.blogspot.com/-eZTpv1NrUoU/TxpZnDGs_DI/AAAAAAAAHcU/VapU9Jy97R8/s1600/suchomimus_2012.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="256" src="http://1.bp.blogspot.com/-eZTpv1NrUoU/TxpZnDGs_DI/AAAAAAAAHcU/VapU9Jy97R8/s640/suchomimus_2012.png" width="640" /></a></div>
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</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com11tag:blogger.com,1999:blog-4172796532462375810.post-74120749532627342572012-01-18T08:26:00.000-08:002012-01-18T10:19:06.278-08:00Just say no to SOPA and PIPA<div dir="ltr" style="text-align: left;" trbidi="on">
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I've generally refrained from talking about subjects not directly related to paleontology and scientific illustration, but since our ability to have these conversations are now under attack, I've decided to make an exception today and add to the chorus of people opposing SOPA and PIPA.<br />
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Both are bills that are intended to protect intellectual property - and given what I do and how I make a living, <i>believe me</i> when I say that protecting intellectual property is an important subject to me. But the bills go (much) too far in crippling online commerce, removing the job of oversight away from the public eye (inviting the censorship of unpopular views, rather than illegal activity), and are unlikely to be effective in combating piracy.<br />
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In short, this bill was written by people who don't understand the internet, and are throwing lots of money and influence at Congress is part of a desperate wish to try and turn back the clock to before the web was available. It <i>won't</i> stop those who are breaking the law. It <i>will</i> legalize tools for government agencies to censor parts of the web. It would slow or stop the economic growth of online companies, including the ones that make blogging possible (both companies like Google's Blogger and WordPress, and also many companies that support paid bloggers with advertising).<br />
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Also, I wanted to point out that this is a bipartisan issue: members of both U.S. parties acted to delay the vote on SOPA in the House of Representatives, and members of both parties are threatening to bring PIPA to a vote in the Senate quickly before more opposition appears. And this will impact U.S. citizens (and the international community) regardless of party affiliation.<br />
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If you want to learn more about the legislation you can read about it <a href="http://en.wikipedia.org/wiki/Wikipedia:SOPA_initiative/Learn_more" target="_blank">here</a>.<br />
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To find a representatives to contact, head over to Wikipedia's <a href="http://en.wikipedia.org/wiki/Main_Page" target="_blank">main page</a>, or to sign a petition go <a href="https://www.google.com/landing/takeaction/" target="_blank">here</a>.<br />
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We'll get back to dinosaurs tomorrow!</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com4tag:blogger.com,1999:blog-4172796532462375810.post-8841725860874309302012-01-11T11:04:00.000-08:002012-01-15T20:56:44.471-08:00Revisiting the Fisher King<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://4.bp.blogspot.com/-q9BDfny53M0/TwxawxCboDI/AAAAAAAAHWY/HZoiAX4rPp0/s1600/spinosaurus.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="242" src="http://4.bp.blogspot.com/-q9BDfny53M0/TwxawxCboDI/AAAAAAAAHWY/HZoiAX4rPp0/s640/spinosaurus.png" width="640" /></a></div>
I know, I know, my last post promised a series on reconstructing <i>Acrocanthosaurus</i> in multiple views - bear with me, as this is actually part of that series. Remember that both animals have stuff sticking up on their backs, so I want to be able to compare and contrast those elongated neural spines...and how those differences should impact reconstructions of the animals. But to do that I had to update this skeletal, as new information had rendered the older one no longer tenable.<br />
<a name='more'></a><a href="http://images.wikia.com/dinosaurs/images/7/73/Tyrannosaurus_vs_Spinosaurus.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><br /><img border="0" height="240" src="http://images.wikia.com/dinosaurs/images/7/73/Tyrannosaurus_vs_Spinosaurus.jpg" width="320" /></a><br />
Besides, <i>Spinosaurus</i> is cool! For one, it's the only dinosaur in the <a href="http://www.amazon.com/gp/product/B005YGCSRI/ref=as_li_tf_tl?ie=UTF8&tag=skeletaldrawi-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=B005YGCSRI" target="_blank">Jurassic Park series</a> to tangle with a <i>T. rex</i> and emerge victorious (no matter how unlikely that outcome was). It's probably the longest theropod we know of, and may have been the heaviest as well. Yet counter-intuitively it shows specialization for piscivory (fish-eating)...maybe in JP3 the spinosaur mistook the <i>T. rex</i> for a really large lung-fish?<br />
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Tongue firmly out of cheek now, <i>Spinosaurus</i> has lit up imaginations partially due to its size, but also because there was so much you had to imagine to try and reconstruct the animal. Until the last decade or two it was sort of a theropod Rorschach test where you could project any sort of oversized monster theropod onto its scant (and now lost) remains. This brings a thrilling "Sherlock Holmes" quality when trying to imagine the living animal, but for most of the last century serious attempts to reconstruct <i>Spinosaurus</i> have been more frustrating than titillating.<br />
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Darren Naish has an excellent <a href="http://blogs.scientificamerican.com/tetrapod-zoology/2011/11/16/the-discovery-and-early-interpretation-of-spinosaurus/" target="_blank">write up</a> of the history (and tragedy) of of the type specimen of <i>Spinosaurus</i>, which I won't duplicate here. The long and short of it is that WWII claimed the fossils as another victim of the conflict. The already-meager remains lost, paleontologists were stuck with the original description and some somewhat uninspired sketches as the only link to the past.<br />
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A series of fortunate events occurred in the latter half of the 20th century that allowed for a more accurate interpretation of <i>Spinosaurus</i> to emerge. For one, other spinosaurids were found. <i><a href="http://en.wikipedia.org/wiki/Baryonyx" target="_blank">Baryonyx</a></i> from the U.K., and Nigerian <i><a href="http://en.wikipedia.org/wiki/Suchomimus" target="_blank">Suchomimus</a></i>, started to paint a more complete picture of what these animals were like. They had bizarrely long snouts that seemed to resemble a <a href="http://weirdimals.wordpress.com/2010/02/03/gharial/" target="_blank">gharial</a> as much as a traditional theropod. Suchomimus even had a smaller version of the enlarged neural spines on the back:<br />
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<a href="http://3.bp.blogspot.com/-7odUPdn1Nvc/TwxiMgmwL4I/AAAAAAAAHWg/UQozK637smo/s1600/suchomimus.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="211" src="http://3.bp.blogspot.com/-7odUPdn1Nvc/TwxiMgmwL4I/AAAAAAAAHWg/UQozK637smo/s640/suchomimus.png" width="640" /></a></div>
The amusingly-named <i><a href="http://en.wikipedia.org/wiki/Irritator" target="_blank">Irritator</a></i> from South America further clarified the relationships and anatomy of spinosaurids. But the real breakthrough was the re-discovery of several photographic plates of the original material. While Spinosaurus wasn't the most complete specimen, having photographs at least made it possible to ensure that what was found is incorporated accurately into a reconstruction.<br />
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<a href="http://qilong.files.wordpress.com/2011/08/spinosaurus-aegyptiacus-mount-preserved.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="237" src="http://qilong.files.wordpress.com/2011/08/spinosaurus-aegyptiacus-mount-preserved.jpg" width="320" /></a></div>
Among other details, the image also shows what had been the basis of attempts to restore the shape of the elongate sail or hump on the back: Stromer's original interpretation for the position of the elongated neural spines. In particular, notice that the tallest one is set directly in front of the sacrum here, while the only associated tail vertebra (at the far left of the picture) has a very short spine. That has lead most people to infer that the spine started quickly after the neck, grew to ridiculous heights over the pelvis, and then quickly dropped off again. Indeed, this is the interpretation that I used in my first attempt, and has been widely seen in such disparate and reputable scientific endeavors as Jurassic Park 3, the Carnegie Collection of "museum quality replicas", and Greg Paul's reconstruction in his Princeton Field Guide to Dinosaurs.<br />
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And they're in excellent company (whereby I arbitrarily define myself as "excellent company"). I had been concerned with Stromer's original interpretation for the placement of the tallest neural spinse - no vertebral body (centrum) was preserved, but the change in the angle of the spine seemed pretty extreme compared to the previous dorsals, especially right in front of the sacrum. My solution was to assume it <i>wa</i>s a sacral neural spine. This largely preserved the traditional appearance of the "sail", but provided a bit of breathing room for the change in orientation.<br />
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<a href="http://2.bp.blogspot.com/-LzTI5-U3suI/Tw3Yc1kUDFI/AAAAAAAAHWo/CoJIerQ1tj0/s1600/spino_comparison_traditional.png" imageanchor="1"><img border="0" height="290" src="http://2.bp.blogspot.com/-LzTI5-U3suI/Tw3Yc1kUDFI/AAAAAAAAHWo/CoJIerQ1tj0/s640/spino_comparison_traditional.png" width="640" /></a></div>
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Luckily for us, <a href="http://theropoda.blogspot.com/2008/12/misteriosi-giganti-del-sahara-quarta.html" target="_blank">Andre Cau</a> and <a href="http://qilong.wordpress.com/2010/05/16/weekly-picture-3-spinosaurus-spines/" target="_blank">Jamie Headden</a> were busy mulling over this specific issue, and came to a much more likely conclusion, that the backward-oriented neural spine was actually an anterior caudal. Looking at a host of dinosaurs with elongate neural spines, they noted that in general you never seen backward-canted spines in front of the hips, you always see them after it. There is a bit more <a href="http://qilong.wordpress.com/2010/05/16/weekly-picture-3-spinosaurus-spines/" target="_blank">detail</a> to the argument (which I encourage you to read on their blogs), but in essence they make a very compelling case.<br />
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And so it was back to the virtual drawing board. I made some other corrections from my previous attempt - there had been some scaling issues with the neck vertebrae that had given my reconstruction a thinner <i>Baryonyx</i>-like profile in the neck. Also, it appears that the necks of these animal don't have as much of the traditional theropod S-curve, so that was changed as well (although I still don't buy the extreme hang-dog look that Greg Paul has started to restore his spinosaurs with). The results are a stockier animal, with a more elongate sail (or hump):<br />
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<a href="http://1.bp.blogspot.com/-9LSDn25AoHQ/Tw3cg5AndcI/AAAAAAAAHWw/RR55DB9vvYU/s1600/spinosaurus.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="476" src="http://1.bp.blogspot.com/-9LSDn25AoHQ/Tw3cg5AndcI/AAAAAAAAHWw/RR55DB9vvYU/s640/spinosaurus.jpg" width="640" /></a></div>
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Looking at the rigorous reconstruction, it's clear that there's still quite a bit of uncertainty in the skeleton, although not all of the missing parts are created equal. Much of the pelvic girdle is known from Irritator, as is the back of the skull. Also, some unpublished specimens shed light on this, even if they aren't documented well enough to be official parts of the reconstruction. Still, there's a bit of ambiguity about the exact limb proportions, the length of the tail, and the exact shape of the sail.<br />
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Speaking of which, how should those tall neural spines be restored by artists doing life reconstructions? Is it a sail, was it supporting a hump of tissue like a bison, or was it simply a muscular ridge? We'll get back to that subject in a bit, after looking at Acrocanthosaurus.<br />
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Until then, best wishes to one and all for a wonderful 2012!</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com12tag:blogger.com,1999:blog-4172796532462375810.post-91392899348288536652011-12-24T21:27:00.000-08:002011-12-24T21:27:23.322-08:00Happy Holidays!<div dir="ltr" style="text-align: left;" trbidi="on">
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<a href="http://2.bp.blogspot.com/-5zVOcEnKt0o/Tvaz8LUrROI/AAAAAAAAHQ8/YytOgfT8w-k/s1600/acrocanthosaurus_holiday.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="562" src="http://2.bp.blogspot.com/-5zVOcEnKt0o/Tvaz8LUrROI/AAAAAAAAHQ8/YytOgfT8w-k/s640/acrocanthosaurus_holiday.png" width="640" /></a></div>
Happy holidays to one and all. We'll talk about that Acro skeletal and multi-view reconstructions in the New Year. Until then, be safe and enjoy the holiday season!<br />
<br /></div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com0tag:blogger.com,1999:blog-4172796532462375810.post-25380117050030644962011-12-20T18:15:00.000-08:002011-12-20T18:17:02.091-08:00Please (properly) label your scale bars: Exhibit A<div dir="ltr" style="text-align: left;" trbidi="on">
As many of you know, I spend a lot of my time doing skeletal drawings. Not everyone does them, but I don't think I demand any special considerations in the papers I use as reference. Many of the critiques about measuring your dinosaur posted over at SVPOW are similar to what I think when I read a paper. Anyhow, in terms of typos making a scale bar useless, I think this next image speaks for itself:<br />
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<a href="http://4.bp.blogspot.com/-dPIoQxLjMy0/TvFA-CRVleI/AAAAAAAAHNQ/rncD-7k69O0/s1600/malawisaurus_cervical.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="580" src="http://4.bp.blogspot.com/-dPIoQxLjMy0/TvFA-CRVleI/AAAAAAAAHNQ/rncD-7k69O0/s640/malawisaurus_cervical.jpg" width="640" /></a></div>
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That is all.<br />
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(If you're having trouble seeing what I'm talking about, read the image caption carefully)</div>
</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com9tag:blogger.com,1999:blog-4172796532462375810.post-41480067811143655852011-11-18T15:40:00.001-08:002011-11-20T02:37:23.440-08:00Falcarius: bizarre sickle-cutter<div dir="ltr" style="text-align: left;" trbidi="on">
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The truly strange looking animal above is <i><a href="http://en.wikipedia.org/wiki/Falcarius">Falcarius utahensis</a></i>. It's an early, omnivorous member of the theropod clade known as <a href="http://en.wikipedia.org/wiki/Therizinosaur">therizinosaurs</a>. Not only does it look weird, it's also a bit different from other skeletals you may have seen on the web. Join me after the break for a bit of a discussion about <i>Falcarius</i>, and the challenges I faced with this reconstruction.<br />
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<a name='more'></a>I should warn you, this won't be a tutorial on how I make my skeletal reconstructions. That would certainly be a fun series, but it would require <i>quite a lot</i> of time to do properly, so for now it'll have to wait. But there are still several points worthy of discussion.<br />
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First off, the animal was discovered in a bone bed of disarticulated individuals. The good news is that most of the individual elements are known, but the down side is the bones aren't all from the same sized animals. That means that cross-scaling is needed to restore the skeleton, but even that presents a challenge; the usual method of cross-scaling involves double-checking the results against the proportions of close relatives. Alas, in this case the fossil record for the base of the therizinosaur family tree isn't well known, and what is known makes it clear that <i>Falcarius</i> has very different proportions than it's closest known relative: <i><a href="http://en.wikipedia.org/wiki/Beipiaosaurus">Beipiaosaurus</a></i>.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="http://2-0.dinosaurier.org/wp-content/uploads/2008/09/falcarius_skelett.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="141" src="http://2-0.dinosaurier.org/wp-content/uploads/2008/09/falcarius_skelett.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Copyright <a href="http://gspauldino.com/index.html">Greg Paul</a></td></tr>
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When the original description of <i>Falcarius</i> was published in 2005, it came with the skeletal drawing at left. Obviously I don't agree with those proportions now, but at the time it had been done when fewer bones had been excavated, prepared, and described in detail, so Greg Paul had to try and scale them based on a smaller amount of material to compare with.<br />
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In fact, given the difficulty of restoring the proportions I intentionally avoided doing a <i>Falcarius</i> skeletal reconstruction for several years. I might have avoided it all together, but towards the end of my tenure at the <a href="http://www.wyodino.org/">WDC</a> we mounted a cast of <i>Falcarius</i> that <a href="http://www.gastondesign.com/">Gaston Design</a> produced. Working on that skeleton I was able to not only measure and photograph all of the elements, but spend time looking at how the individual elements were matched up. Some parts of the cast's vertebral column are from different sized individuals (an unavoidable consequence of trying to piece together a skeleton from several different individuals). In other cases, vertebrae I had assumed to be from different sized animals were in fact crushed.<br />
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<a href="http://www.oucom.ohiou.edu/dbms-witmer/collections/images/Falcarius_cast_(00).jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="178" src="http://www.oucom.ohiou.edu/dbms-witmer/collections/images/Falcarius_cast_(00).jpg" width="320" /></a></div>
In addition to the hands-on data, Lindsay Zanno had been hard at work publishing more detailed information on <i>Falcarius </i>(this is actually notable, as not all researchers are as timely with getting more detailed descriptions of a new animal into print).<br />
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As the information piled up I felt that a skeletal was possible to be done. I still didn't tackle it though, as there were plenty of "low-hanging fruit" skeletals that could be done from less-challenging animals.<br />
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As luck would have it, I ended up being asked to produce a skeletal of <i>Falcarius </i>for a display in the new Utah Museum of Natural History building (side note: the new <a href="http://nhmu.utah.edu/">UMNH</a> building just opened, and houses one of the most impressive natural history displays in North America, go see it!).<br />
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Since I was working with the UMNH, I got valuable input from several of the researchers who worked on the specimens. They were able to provide additional information - I won't go into the nitty-gritty of it (although you <a href="http://uwp.academia.edu/LindsayZanno/Papers/159107/Osteology_of_Falcarius_utahensis_Dinosauria_Theropoda_characterizing_the_anatomy_of_basal_therizinosaurs">may</a> if you would like), but I wanted to point out that the end result was quite a surprise to me. And little is more satisfying than when you are really surprised at the end of a skeletal reconstruction.<br />
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<a href="http://gastondesign.com/07galleries/dinoartics/p7hg_img_1/fullsize/falc-arm_fs.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="113" src="http://gastondesign.com/07galleries/dinoartics/p7hg_img_1/fullsize/falc-arm_fs.jpg" width="320" /></a></div>
Resulting skeletal in hand, you can compare it to the most recent studies of the therizinosaur family tree, as well as the excellent research being done by Lindsay Zanno and Peter Makovicky on the origin of plant-eating in theropod dinosaurs, and <i>Falcarius </i>starts to tell an interesting tail about the order in which therizinosaur traits appeared.<br />
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<i>Falcarius</i> appears to already be specialized for browsing for high forage. Given the lack of an enlarged gut for fermentation it probably preferred to seek out higher-quality plant matter, like fruiting bodies or seeds. The partially upright stance appears concurrently with a widening of the passage through the pelvis (not visible in side view) allowing move guts into that area, causing the center of gravity to sit further back despite the elongation of the neck.<br />
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The large hand claws (from which the authors derived the name "sickle-cutter") may have allowed <i>Falcarius</i> to pick up small prey, but they also may have served as defense for a fairly slow animal with small teeth. The first toe is low and long enough to start interacting with the ground, perhaps to provide balance and stability when browsing high. All of these features would be carried to extremes in advanced therizinosaurs, but they seem to already be playing the same (albeit incipient) functional roles in <i>Falcarius</i>.<br />
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So with <i>Falcarius</i> we have an animal that at first glance appears inexplicably strange, but when viewed through the lens of where it was coming from (long-bodied small-headed meat eaters) and where it ends up (the upright, pot-bellied therizinosaurs) the combination of traits start to make a lot of sense.<br />
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<a href="http://2.bp.blogspot.com/-eTqrg8grKfE/TsjYPSOHhlI/AAAAAAAAG9g/rOstUGMbhZE/s1600/therizinosaur+sequence.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="330" src="http://2.bp.blogspot.com/-eTqrg8grKfE/TsjYPSOHhlI/AAAAAAAAG9g/rOstUGMbhZE/s640/therizinosaur+sequence.png" width="640" /></a></div>
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Isn't science grand?<br />
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References:<br />
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Kirkland, J. I., Zanno, L. E., Sampson, S. D., Clark, J. M. & DeBlieux, D. D., 2005. A primitive therizinosauroid dinosaur from the Early Cretaceous of Utah. Nature, v435, pp 84-87. <span style="font-family: sans-serif; font-size: x-small;"><span style="line-height: 19px;"><br /></span></span><br />
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Zanno, L. E. 2006. The pectoral girdle and forelimb of the primitive therizinosauroid <i>Falcarius utahensis</i> (Theropoda, Maniraptora): Analyzing evolutionary trends withing Therizinosauroidea. Journal of Vertebrate Paleontology, v26 n3, pp 636-650.<br />
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Zanno, L. E. 2010. <a href="http://uwp.academia.edu/LindsayZanno/Papers/159107/Osteology_of_Falcarius_utahensis_Dinosauria_Theropoda_characterizing_the_anatomy_of_basal_therizinosaurs">Osteology of <i>Falcarius utahensis</i> (Dinosauria: Theropoda): characterizing the anatomy of basal therizinosaurs</a>. Zoological Journal of the Linnean Society. v158, pp 196-230.<br />
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Zanno, L. E. & Makovicky, P. J., 2011. Herbivorous ecomorphology and specialization patterns in theropod dinosaur evolution. Proceedings of the National Academy of Sciences. v108 m1, pp 232-237.<br />
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</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com8tag:blogger.com,1999:blog-4172796532462375810.post-63721107453381451292011-11-11T12:08:00.001-08:002011-11-14T11:21:02.354-08:00Gauging stance in "wide-gauge" sauropods<div dir="ltr" style="text-align: left;" trbidi="on">
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In 1999 Jeff Wilson and Matt Carrano published an excellent paper addressing the phenomena of "wide-gauge" sauropod trackways. For years researchers had been working to explain why sauropod trackways seemed to come in two very different flavors - some of them were very closely spaced...so much so that they would actually overlap on the midline of the track. Other sauropod tracks seemed to show animals walking with their feet spread much further apart.<br />
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What were paleontologists to make of this?<br />
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<a name='more'></a>One explanation was that the trackways were made by the same type of sauropods that were engaging in different behaviors. In other words, perhaps sometimes a sauropod would walk with its legs close in, while at other times it would use a wide-gauge stance. <br />
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Wilson & Carrano proposed that instead the trackways were made by sauropods with different skeletal adaptations. They mustered quite a few lines of evidence, but perhaps the best was that there was a group of sauropods - titanosaurs - that in fact had a much wider pelvis than other sauropods. The paper created a framework for later workers to use when attempting to correlate track makers with fossilized trackways, and is generally a towering success.<br />
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But I did want to take issue with one figure of the paper - one that pops up repeatedly at SVP. It is figure 5, demonstrating their interpretation of hing leg stance:<br />
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That's Camarasaurus on the left and Opisthocoelicaudia on the right. The clever reader may have already surmised from the title of this post that I think the animal on the right has its legs spread too far apart. But I have a larger issue: <i>both</i> animals have their legs spread <i>much</i> too far apart.</div>
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Remember that narrow-gauged trackways actually have their feet fall so close together that they frequently overlap along the midline. There's no way even sauropod "A" could make those tracks in the stance as figured. And this is why I'm bringing this up, because animals generally don't walk around with their legs acting as perfectly vertical beams. If you spend time watching large animals walk away from you, you'd see something like this:</div>
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-29x6XF1EbHI/Tr2Ji5b8C4I/AAAAAAAAG78/0_9U4NkAP-g/s1600/graviportal+stance.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="320" src="http://4.bp.blogspot.com/-29x6XF1EbHI/Tr2Ji5b8C4I/AAAAAAAAG78/0_9U4NkAP-g/s400/graviportal+stance.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Elephant image from <a href="http://tommyimages.com/Stock_Photos/Africa/Tanzania/Ngorongoro/slides/Tanzania_4329-Elephant_Walking-orig.html">here</a>, rhino image from <a href="http://www.wildlife-pictures-online.com/rhino_knp-0364.html">here</a>.</td></tr>
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People also move like this, with our vertical limbs generally sloping in toward the midline when we walk or run. There are probably several reasons for this (including mechanical efficiency) but for our purposes here let's just setting on the fact that it happens. Large, straight-limbed graviportal animals tend to walk with the limbs angled inward, not down (and certainly not angled out).<br />
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And the trackways also demonstrate this. If you place place sauropods over the actual trackways in question, you end up with a stance more like this:<br />
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<a href="http://3.bp.blogspot.com/-sFublRIM_7c/Tr2MLDZcK9I/AAAAAAAAG8E/--Ttx1Z-6og/s1600/wide+gauge_finish.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="http://3.bp.blogspot.com/-sFublRIM_7c/Tr2MLDZcK9I/AAAAAAAAG8E/--Ttx1Z-6og/s640/wide+gauge_finish.jpg" width="556" /></a></div>
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In this case I've put a diplodocid (<i>Supersaurus</i>) on the left, while the animal on the right is scaled to the pelvic dimensions of <i>Opisthocoelicaudia </i>as seen in the original paper. Both animals have the hind legs mostly vertical but gently sloping inward.<br />
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This is not to say that sauropods never adopted a pose with their legs spread out a bit; Wilson & Carrano point out that titanosaurs have adaptations that may have allowed them to evert their hind limbs more effectively. They suggest that titanosaurs may have done so when rearing up, or during other activities that require greater stability. <br />
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I don't take issue with that, and those sorts of differences in the legs and pelvis may make it possible to tease out further behavioral differences between sauropod groups. But when walking around in their day to day lives both the footprints and modern analogs make a strong case that the limbs should be vertical, and if anything sloping in towards the midline rather than spread away from it.<br />
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Reference:<br />
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Wilson, J. A, & Carrano, M. T. 1999. Titanosaurs and the origin of "wide-gauge" trackways: a biomechanical and systematic perspective on sauropod locomotion. <i>Paleobiology</i>, 25(2), pp. 252-267.</div>Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com6tag:blogger.com,1999:blog-4172796532462375810.post-30300680422252512212011-09-30T21:08:00.000-07:002011-11-14T11:22:58.343-08:00Um hey, Scientific American? Bird knees bend the same way as everyone else.<div dir="ltr" style="text-align: left;" trbidi="on">
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Ok, time for a quick anatomy lesson: Despite what you may have heard, bird knees do <i>not</i> bend backward. Nor, in fact, do the knees of any <a href="http://en.wikipedia.org/wiki/Tetrapod">tetrapod</a> perform this trick. Given the role of the knee in locomotion, it's not even clear how such a reversal could evolve after the initial "knee bend" direction was settled upon several hundred million years ago.<br />
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Why bring the anatomical equivalent of a fairy tale? Well, it's a fairly common misconception. So common, in fact, that it was recently enshrined by none other than <a href="http://blogs.scientificamerican.com/observations/2011/09/28/turkey-legs-tell-the-tale-of-our-unsung-tendons/?WT.mc_id=SA_Twitter_katherineharmon">Scientific American</a>. So let's see if we can clear this up after the break:<br />
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It's a surprisingly common mistake. When looking at living birds many people fail to realize that part of the leg is hidden on a bird; the upper leg barely moves, and along with the knee it is actually buried up under the feathers of the wing and body. Birds also have quite long ankles, leaving their ankle joints in roughly the position we'd expect the knees to be on a human. Like this:<br />
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<a href="http://ibc.lynxeds.com/files/imagecache/photo_940/pictures/Dara_Double-striped_Thick-knee_Burhinus_bistriatus_vocifer.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="http://ibc.lynxeds.com/files/imagecache/photo_940/pictures/Dara_Double-striped_Thick-knee_Burhinus_bistriatus_vocifer.JPG" width="256" /></a></div>
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The key here is that people are <a href="http://en.wikipedia.org/wiki/Plantigrade">plantigrade</a> animals, while all theropods (including birds) are <a href="http://en.wikipedia.org/wiki/Digitigrade">digitigrade</a>. That means that human ankles are flat on the ground, and in our case our knees are roughly in the middle of our legs. In birds and other digitigrade animals (most dinosaurs and many mammals, like dogs, deer, and horses) it's only the toes that contact the ground. The ankle joint is well up off the ground, and the knee is is actually in the upper 1/3rd of the leg. And in birds the thigh is actually even a smaller part of the leg, and as mentioned above is also mostly hidden under feathers. Here's a look comparing the same leg portions of a human (in two poses), a dog, and an extinct bird:<br />
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<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-ubuoiEOhePk/ToaKHJdAglI/AAAAAAAAGak/j4jxoSGotb0/s1600/hind_limb_comparative_anatomy.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="304" src="http://4.bp.blogspot.com/-ubuoiEOhePk/ToaKHJdAglI/AAAAAAAAGak/j4jxoSGotb0/s640/hind_limb_comparative_anatomy.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Presbyornis</i> Copyright Scott Hartman, other skeletals modified after Charles Knight.</td></tr>
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In the diagram the thigh bones (femora) are all colored red, the shin bones and proximal ankle bones are colored blue, the "foot bones" (the distal tarsals and the metatarsals) are green, and the individual toe bones are yellow. Notice that the femur of the <i>Presbyornis </i>is small and very high, and the knee (the joint between the red and blue bones) is up where it would be hidden by the body and wings. But please also notice...the knee is bending the same way as ours. And the same way as everything else that has a spine and walks on land.<br />
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Which brings us back to the <a href="http://blogs.scientificamerican.com/observations/2011/09/28/turkey-legs-tell-the-tale-of-our-unsung-tendons/?WT.mc_id=SA_Twitter_katherineharmon">article</a> posted by Scientific American. I don't want to go too far with "gotcha" blogging; Scientific American is generally one of the more accurate popularizers of science on the web and in print. I took a look the other pieces published by the author, and she seems like a solid reporter that just happens to have made a mistake. Journalists don't get science degrees (and even if they did that would only be one subject), so this should not be construed as an attack.<br />
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But at the same time, this is a serious error. It's like reporting that September has 32 days in it, or that the <a href="http://sportsillustrated.cnn.com/2011/writers/cliff_corcoran/09/29/greatest.collapses.ever/index.html">Red Sox</a> clinched a playoff spot this week. Only worse, as it's perpetuating a myth that gets passed around as "common knowledge". I attempted to bring this to the attention of the relevant parties shortly after it was reported, both on <a href="http://plus.google.com/">Google+</a>, where SciAm blog editor <a href="https://plus.google.com/107991184034868817056/posts">Bora Zivkovic</a> has been making effective use of the new social network, and the author's Twitter account (which is frequently used). Despite near real-time feedback, days have gone by with no correction. <br />
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Making a mistake is understandable, but failing to correct it is not. Scientific American has written <a href="http://www.scientificamerican.com/search/?q=science+education&x=0&y=0">hundreds of articles</a> on the state of science education, and has often been an effective advocate for <a href="http://blogs.scientificamerican.com/guest-blog/2011/08/04/can-scientists-reform-science-education/">ways to improve</a> it. But the authority they derive comes from their attention to scientific detail, so I hope we will now see a quick correction without further delay.</div>
Scott Hartmanhttp://www.blogger.com/profile/00195833796668977878noreply@blogger.com25