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Wedel and Taylor (2013a) on sauropod neural spine bifurcation March 15, 2013

The paper Wedel, Mathew J., and Michael P. Taylor. 2013. Neural spine bifurcation in sauropod dinosaurs of the Morrison Formation: ontogenetic and phylogenetic implications. Palarch’s Journal of Vertebrate Palaeontology 10(1):1-34. ISSN 1567-2158. (http://www.palarch.nl/wp-content/Wedel-and-Taylor-2013-Neural-spine-bifurcation-in-sauropod-dinosaurs-PJVP-10-11.pdf)

SV-POW! posts – pre-publication This paper is a departure for us in that we wrote it as a series of blog posts first, and then turned those posts into the submitted manuscript. Here are the original posts, from April, 2012: Part 1: what we knew a month ago (https://svpow.com/2012/04/05/neural-spine-bifurcation-in-sauropods-what-we-knew-a-month-ago/) Part 2: why serial position matters (https://svpow.com/2012/04/09/neural-spine-bifurcation-in-sauropods-part-2-why-serial-position-matters/) Part 3: the evidence from ontogenetic series (https://svpow.com/2012/04/10/neural-spine-bifurcation-in-sauropods-part-3-the-evidence-from-ontogenetic-series/) Part 4: is Suuwassea a juvenile of a known diplodocid? (https://svpow.com/2012/04/12/neural-spine-bifurcation-in-sauropods-part-4-is-suuwassea-a-juvenile-of-a-known-diplodocid/) Part 5: is Haplocanthosaurus a juvenile of a known diplodocid? (https://svpow.com/2012/04/14/neural-spine-bifurcation-in-sauropods-part-5-is-haplocanthosaurus-a-juvenile-of-a-knowndiplodocid/) Part 6: more reasons why Haplocanthosaurus is not a juvenile of a known diplodocid (https://svpow.com/2012/04/15/neural-spine-bifurcation-in-sauropods-part-6-more-reasons-whyhaplocanthosaurus-is-not-a-juvenile-of-a-known-diplodocid/) Inconsistent fusion in Haplocanthosaurus sacra (https://svpow.com/2012/04/29/inconsistent-fusion-in-haplocanthosaurus-sacra/) And posts about the VertFigure software that we wrote and used to create figure 9: Introducing vcd2svg: how we made the vertebral-bifurcation heat-map figure (https://svpow.com/2014/04/07/introducing-vcd2svg-how-we-made-the-vertebral-bifurcation-heat-mapfigure/) Introducing VertFigure, a better name for vcd2svg (https://svpow.com/2014/04/12/introducing-vertfigure-a-better-name-for-vcd2svg/) Play with VertFigure online (https://svpow.com/2016/03/02/play-with-vertfigure-online/) and the post that started it all: Changes through growth in sauropods and ornithopods (https://svpow.com/2012/03/29/changes-through-growth-in-sauropods-and-ornithopods/)

SV-POW! posts – post-publication Our neural spine bifurcation paper is out (https://svpow.com/2013/03/15/our-neural-spine-bifurcation-paper-is-out/) Neural spine paper: new file available (https://svpow.com/2013/03/16/neural-spine-paper-new-file-available/) Introducing vcd2svg: how we made the vertebral-bifurcation heat-map figure (https://svpow.com/2014/04/07/introducing-vcd2svg-how-we-made-the-vertebral-bifurcation-heat-mapfigure/) Introducing VertFigure, a better name for vcd2sv (https://svpow.com/2014/04/12/introducing-vertfigure-a-better-name-for-vcd2svg/)

Nexus files The Nexus files we used to run the phylogenetic analyses in the paper are available on FigShare: Nexus file for Taylor (2009) matrix with our constraints (http://figshare.com/articles/Taylor_2009_Brachiosaurus_paper_Nexus_file/643806) Nexus file for Whitlock (2011) matrix with our constraints (http://figshare.com/articles/_Wedel_Taylor_2013_Nexus_file_based_on_Whitlock_2011_matrix/643805)

High-resolution figures

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-1-apatosaurus-ajaxcervical.jpg) Figure 1. A cervical vertebra of Apatosaurus ajax YPM 1860 showing complete bifurcation of the neural spine into paired metapophyses. In dorsal (top), anterior (left), left lateral (middle), and posterior (right) views.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-2-consensus-tree.jpg) Figure 2. Consensus phylogeny of sauropods based on the strict consensus trees of Taylor (2009), Ksepka & Norell (2010) and Whitlock (2011). The first of these provides the skeleton of the tree including outgroups, basal sauropods and macronarians; the second gives the positions of Erketu and Qiaowanlong; the last provides a detailed phylogeny of Diplodocoidea. Taxa with bifid neural spines are highlighted in blue. Haplocanthosaurus and Suuwassea, whose positions are disputed by Woodruff & Fowler (2012) are shown in bold.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-3-human-cervicalvertebra.jpg) Figure 3. A middle cervical vertebra of a human in cranial view showing paired bony processes for the attachment of dorsal muscles to the neural spine. Uncatalogued specimen from the anthropology teaching collection at the University of California, Santa Cruz.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-4-classes-ofbifurcation.jpg) Figure 4. Cervical vertebrae of Camarasaurus supremus AMNH 5761 cervical series 1 in anterior view, showing different degrees of bifurcation of the neural spine. Modified from Osborn & Mook (1921: plate 67).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-5-apatosaurus-sacracompared.jpg) Figure 5. Sacra of Apatosaurus excelsus holotype YPM 1980 (left) and A. ajax holotype YPM 1860 (right) in ventral view and at the same scale, modified from Ostrom & McIntosh (1966: plates 27 and 29).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-6-giant-oklahomaapatosaurus-dorsals.jpg) Figure 6. From left to right: Apatosaurus sp. OMNH 1670 D?5 in anterior view, A. louisae CM 3018 D5 in anterior view, and A. sp. OMNH 1382 in posterior view. Total heights of the vertebrae are 1350 mm, 1060 mm, and 950 mm, respectively, although OMNH 1382 would have been somewhat taller when the spine was intact. The arrow next to OMNH 1382 points to the unfused neurocentral synchondrosis.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-7-small-diplodocuscervical1.jpg) Figure 7. BYU 12613, a posterior cervical of Diplodocus, in dorsal (top), left lateral (left), and posterior (right) views. It compares most favourably with C14 of D. carnegii CM 84/94 (Hatcher, 1901: plate 3) despite being only 42% as large, with a centrum length of 270 mm compared to 642 mm for C14 of D. carnegii.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-8-diplodocus-c3-and-c15compared.jpg) Figure 8. Third and fifteenth cervical vertebrae of Diplodocus carnegii CM 84/94 in posterior view. The cotyle diameters of the vertebrae are 69 and 245 mm, respectively. Modified from Hatcher (1901: plate 6).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-9-bifurcatogram.jpg) Figure 9. Degree of neural spine bifurcation of presacral vertebrae in well-preserved Morrison Formation sauropod specimens representing several taxonomic groups. In all taxa with deep bifurcations, these are concentrated around the cervico-dorsal transition. ‘No data’ markers may mean that the vertebrae are not preserved (e.g., posterior dorsals of Suuwassea emilieae ANS 21122), that the degree of bifurcation cannot be assessed (e.g., anterior cervicals of Barosaurus lentus AMNH 6341), or that the serial positions of the vertebrae are uncertain so they contribute no information on serial changes in bifurcation (e.g., the four cervical vertebrae known for Barosaurus lentus YPM 429). The Camarasaurus specimens are roughly in ontogenetic order: C. lentus CM 11338 is a juvenile, C. grandis YPM 1905 and GMNH-PV 101/WPL 1995, and C. supremus AMNH 5761 are adults, and C. lewisi BYU 9047 is geriatric. See text for sources of data.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-10-apatosaurus-parvusanterior-cervicals-from-gilmore.jpg) Figure 10. Apatosaurus parvus UWGM 15556 (formerly A. excelsus CM 563) cervicals 7, 5, 4 and 3 in anterior (top) and right lateral views, showing that neural spines of anterior cervicals are unsplit even in adult diplodocids. From Gilmore (1936: plate 31).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-11-apatosaurus-parvusdorsals-from-gilmore.jpg) Figure 11. Apatosaurus parvus UWGM 15556 D4 (left) and D3 (right) in anterior (top), right lateral, and posterior views, showing that neural spine bifurcation generally does not persist farther back than the mid-dorsals even in adult diplodocids. From Gilmore (1936: plate 32).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-12-camarsaurus-dorsalcomparison.jpg) Figure 12. Serially comparable dorsal vertebrae in different Camarasaurus species or ontogenetic stages. Left: dorsal vertebra 7 (top) and dorso-sacral (= D11) (bottom) of C. supremus AMNH 5760 and 5761 “Dorsal Series II” both in posterior view, with unsplit neural spines. Modified from Osborn & Mook (1921: plate 71). Right: dorsal vertebrae 7-11 of C. lewisi holotype BYU 9047 in posterodorsal view, with split spines. From McIntosh, Miller et al. (1996: plate 5). Scaled so that the height of D11 is roughly equivalent in the two specimens.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-13-diplodocus-cervicalsfrom-hatcher.jpg) Figure 13. Cervical vertebrae of Diplodocus carnegii CM 84/94 in right lateral view. Note the increasing complexity of the laminae and pneumatic cavities in successively posterior cervicals. From Hatcher (1901: plate 3).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-14-plateosauruscervicals.jpg) Figure 14. Plateosaurus engelhardti (originally P. trossingensis) SMNS 13200 cervical vertebrae 3-8 in left lateral view, showing the gradual acquisition of diapophyseal laminae in successively posterior cervicals. The PODL becomes strongly developed in the dorsal vertebrae. C8 is roughly 15 cm long. Abbreviations (after Wilson, 1999): PCDL, posterior centrodiapophyseal lamina; PODL, postzygodiapophyseal lamina; PRDL, prezygodiapophyseal lamina.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-15-mor-cervicalcompared-to-diplodocus.jpg) Figure 15. An isolated cervical of cf. Diplodocus MOR 790 8-10-96-204 (A) compared to D. carnegii CM 84/94 C5 (B), C9 (C), and C12 (D), all scaled to the same centrum length. Actual centrum lengths are 280 mm, 372 mm, 525 mm, and 627 mm for A-D respectively. MOR 790 8-10-96-204 modified from Woodruff & Fowler (2012: figure 2B), reversed left to right for ease of comparison; D. carnegii vertebrae from Hatcher (1901: plate 3).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-16-mor-dorsal-comparedto-apatosaurus.jpg) Figure 16. Diplodocid anterior dorsal vertebrae. Left and right, dorsal vertebrae 3 and 4 of adult Apatosaurus louisae holotype CM 3018, from Gilmore (1936: plate 25). Center, juvenile neural arch MOR 790 7-17-96-45, modified from Woodruff & Fowler (2012: figure 5B), corrected for shearing and scaled up.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-17-apatosauruscaudals.jpg) Figure 17. Apatosaurus parvus CM 563/UWGM 15556 caudals 8 and 7 in right lateral (top) and posterior view, from Gilmore (1936: plate 33). Arrows highlight shallow antero-posterior notches in the tips of the neural spines.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-18-barosaurus-andsupersaurus-cervicals.jpg) Figure 18. Middle cervical vertebrae of Barosaurus AMNH 6341 (top) and Supersaurus BYU 9024 (bottom) in left lateral view, scaled to the same centrum length. The actual centrum lengths are 850 mm and 1380 mm, respectively. BYU 9024 is the longest single vertebra of any known animal.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-19-suuwassea-cervicalcomparison.jpg) Figure 19. The sixth cervical vertebrae of Diplodocus carnegii CM 84/94, Suuwassea emilieae ANS 21122, and Apatosaurus sp. CM 555 in left lateral view, scaled to the same centrum length. Actual centrum lengths are 442 mm, 258 mm, and 327 mm, respectively. Diplodocus carnegii modified from Hatcher (1901: plate 3), reversed left to right for ease of comparison. Suuwassea emilieae from a photo provided by Jerry Harris; the same photo also appears as Harris (2006c: text-figure 7B). Apatosaurus photographs by Mathew Wedel, digitally composited by Michael Taylor.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-20-haplocanthosauruspelvis-comparison.jpg) Figure 20. Pelves of diplodocids and Haplocanthosaurus. From left to right: Apatosaurus excelsus CM 568, Diplodocus carnegii CM 84/94, and Haplocanthosaurus priscus CM 572. All in left lateral view. From Hatcher (1903: plate 4).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-21-haplocanthosauruscervical-comparison-lateral.jpg) Figure 21. Posterior, mid and anterior cervical vertebrae, in right lateral view, of (top to bottom), Haplocanthosaurus, Apatosaurus louisae CM 3018 (from Gilmore, 1936: plate 24, reversed for ease of comparison) and Diplodocus carnegii CM 84/94 (from Hatcher, 1901: plate 3), scaled to roughly the same size. For the diplodocids, we illustrate C13, C9 and C4. For Haplocanthosaurus, we illustrate C14 of H. priscus (from Hatcher, 1903: plate 1) and C9 and C4 of H. utterbacki (from plate 2).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-22-haplocanthosauruscervical-comparison-posterior.jpg) Figure 22. Posterior cervical vertebrae C15 and C14, in posterior view, of (top to bottom), Haplocanthosaurus priscus CM 572 (from Hatcher, 1903: plate 1), Apatosaurus louisae CM 3018 (from Gilmore, 1936: plate 24) and Diplodocus carnegii CM 84/94 (from Hatcher, 1901: plate 6), scaled to the same centrum-to-neural-spine height (these are the only Haplocanthosaurus cervical vertebrae that Hatcher illustrated in posterior view.)

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-23-haplocanthosaurus-dorsalcomparison-lateral.jpg) Figure 23. Posterior, middle and anterior dorsal vertebrae, in right lateral view, of (top to bottom), Haplocanthosaurus, Apatosaurus louisae CM 3018 (from Gilmore, 1936: plate 25, reversed for ease of comparison) and Diplodocus carnegii CM 84/94 (from Hatcher, 1901: plate 7), scaled to roughly the same size. For the diplodocids, we illustrate D9, D5 and D2. For Haplocanthosaurus, which has four more dorsals, we illustrate D13 and D7 of H. priscus (from Hatcher, 1903: plate 1) and D2 of H. utterbacki (from plate 2).

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-24-haplocanthosaurusdorsal-comparison-posterior.jpg) Figure 24. Posterior, mid and anterior dorsal vertebrae, in posterior view, of (top to bottom), Haplocanthosaurus priscus CM 572 (from Hatcher, 1903: plate 1), Apatosaurus louisae CM 3018 (from Gilmore, 1936: plate 25) and Diplodocus carnegii CM 84/94 (from Hatcher, 1901: plate 7), scaled to the same height of the mid dorsal. For the diplodocids, we illustrate D9, D5 and D1. For Haplocanthosaurus, which has four more dorsals, we illustrate D13, D6 and D1.

(https://svpow.files.wordpress.com/2013/03/wedel-and-taylor-2013-bifurcation-figure-25-haplocanthosaurusneural-spine-fusion.jpg) Figure 25. Neurocentral fusion in Haplocanthosaurus. A, B. Posterior cervical vertebra C?12 of sub-adult H. utterbacki holotype CM 879: A, X-ray in right lateral view; B, transverse CT slice showing separate ossificaton of centrum and neural arch. C, D. Mid-dorsal vertebra D6 of adult H. priscus holotype CM 572: X-rays in (C) right lateral and (D) posterior view, showing fully fused neural arch. Modified from Wedel (2009: figure 6). Posted by Matt Wedel Filed in 10 Comments »

The sauropod neck mass project: an experiment in open science March 4, 2013

(https://svpow.files.wordpress.com/2013/02/brachiosaurus-sp-byu-12866-c5-with-ct-slices.png) Brachiosaurus sp. BYU 12866 c5? in left lateral view with CT slices, some corrected for distortion. Last Tuesday Mike popped up in Gchat to ask me about sauropod neck masses. We started throwing around some numbers, derived from volumetric estimates and some off-the-cuff guessing. Rather than tell you more about it, I should just paste our conversation, minimally edited for clarity and with a few hopefully helpful links thrown in. Mike: Dud. Neck masses. Matt: What about ’em? Mike: Taylor (2009:803) (http://www.miketaylor.org.uk/dino/pubs/taylor2009/Taylor2009-brachiosaurus-and-giraffatitan.pdf) measured the neck of Giraffatitan by GDI (https://svpow.com/2011/01/20/tutorial-11-graphic-double-integration-or-weighing-dinosaurs-on-the-cheap/) as 4117 liters. Matt: k Mike: I didn’t convert that to a mass, but I guess density of 0.5 is as good as any, which gives us (say) 2 tonnes. Matt: That works for me. Mike: That’s for an 8.5 m neck. So Supersaurus at 15 … Matt: Yep. Almost twice as long, and not much more slender, and from what I’ve seen, ASP about the same. Mike: Is 1.76 times as long. If it was isometric with the G. neck, it would be 5.5 times as heavy, which is 11 tonnes. Matt: Oh. Mike: So first: yeesh. Like, that is the mass of a whole freaking Diplo. Now we surely have to say isometry is unlikely. Matt: Prolly. Mike: But just multiplying out by length is unrealistic too. So maybe I should guess at mass =~ l^2? If I went with that, I’d get 6410 kg, which is elephant mass. Matt: Something just occurred to me. Like, just now. For my 2006 poster, I calculated the mass of the cervical series in Giraffatitan, by summing over the CT slices from Brachiosaurus sp. BYU 12866 and multiplying by appropriate scale factors for the rest of the verts. We could “skin” that in muscle, and actually figure this out, for various muscle thicknesses, for one sauropod. Mike: We should totally do that … if we had some idea how heavily muscled it was. Matt: Well, obviously the thing to do is what Hutch et al. (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0026037) did for the tyrannosaurs, and put on several soft tissue envelopes. Crazy skinny, our best guess, markedly unfit, OMG, etc. It’s not that much more work. In fact, that could be my SVPCA talk this year. Mike: Sure, but that’s just how to mitigate our ignorance. All we’d be doing at this point is taking n guesses instead of one. But, yeah, we should do it. Or you should if you prefer. Matt: Let’s make it a Wedel and Taylor. I’ll crunch the numbers, but I want your input. Mike: Works for me! Matt: Good. Now let’s file it until April at least.

(https://svpow.files.wordpress.com/2013/02/figure-7-small-adult-diplodocus-cervical.png) BYU 12613, a posterior cervical probably referable to Diplodocus, in dorsal (top), left lateral (left), and posterior (right) views. It most closely resembles C14 of D. carnegii CM 84/94 (Hatcher 1901: plate 3) despite being less than half as large, with a centrum length of 270 mm compared to 642 mm for C14 of D. carnegii. From Wedel and Taylor (in press). Matt: Oh! Matt: Also. Matt: You know that little Diplo cervical from BYU that we figure in our in-press paper? Mike: I think I know the one, yeah. Matt: I am SUCH a moron. I have CT scans of the whole thing. Mike: Good. Matt: I forgot that Kent and I scanned it back in 2008. Even blogged about it (https://svpow.com/2010/02/05/sauropod-related-travel-utah-2008/), fer cryin’ out loud. So I can do the sumover-slices, scale-for-other-verts thing for Diplodocus, too. Which is at least closer to Supes than JANGO (https://svpow.com/2008/07/17/mike-with-boba/) is. Mike: Remind me, is it from a juvenile? Matt: Maybe, maybe not. It IS tiny, but the neural spine is fused (https://svpow.com/2008/01/26/tutorial-5-neurocentral-fusion/), the internal structure is crazy complex, and it doesn’t have any obvious juvenile characters other than just being small. The ASP (https://svpow.com/2008/08/12/air-space-proportion-in-pneumatic-sushi/) is about as high as it gets in diplodocids. Which, as you may remember, is not nearly as high as it gets in titanosauriforms–that’s another paper that needs writing. Damn it. To know all this stuff and not have told it yet is killing me. Mike: PeerJ! (http://peerj.com/) Matt: I know! Mike: Bottom line, it’s nuts that no-one has ever even tried to weigh a sauropod neck.* We should definitely do it, even if we do a really crappy job, if only so that others feel obliged to rebut. Matt: Quite. Let’s do it. For reals. Mike: In April. Done. * R. McNeill Alexander (1985, 1989) did estimate the mass of the neck of Diplodocus, based on the old Invicta model (http://www.dinotoyblog.com/2010/09/09/diplodocus-invicta/) and assuming a specific gravity of 1.0. Which was a start, and waaay better than no estimate at all. Still, let’s pretend that Mike meant “tried based on the actual fossils and what we know now about pneumaticity”. The stuff about putting everything off until April is in there because we have a March 31 deadline to get a couple of major manuscripts submitted for an edited thingy. And we’ve made a pact to put off all other sciencing until we get those babies in. But I want to blog about this now, so I am. Another thing Mike and I have been talking a lot about lately is the relation between blogging and paper-writing. The mode we’ve seen most often is to blog about something and then repurpose or rewrite the blog posts as a paper. Darren paved the way on this (at least in our scientific circle–people we don’t know probably did it earlier), with “Why azhdarchids were giant storks (http://darrennaish.blogspot.com/2006/04/why-azhdarchids-were-giant-storks_03.html)“, which became Witton and Naish (2008) (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0002271). Then last year our string of posts (starting here (https://svpow.com/2012/04/05/neural-spine-bifurcationin-sauropods-what-we-knew-a-month-ago/)) on neural spine bifurcation in Morrison sauropods became the guts–and most of the muscles and skin, too–of our in-press paper on the same topic. But there’s another way, which is to blog parts of the science as you’re doing them, which is what Mike was doing with Tutorial 20 (https://svpow.com/2013/01/10/tutorial-20-how-tomeasure-necks-using-duplo/)–that’s a piece of one of our papers due on March 31. Along the way, we’ve talked about John Hawks’ model of using his blog as a place to keep his notes (http://johnhawks.net/weblog/hawks/about.html). We could, and should, do more of that, instead of mostly keeping our science out of the public eye until it’s ready to deploy (which I will always favor for certain projects, such as anything containing formal taxonomic acts). And I’ve been thinking that maybe it’s time for me–for us–to take a step that others have already taken, and do the obvious thing. Which is not to write a series of blog posts and then decide later to turn it into a paper (I wasn’t certain that I’d be writing a paper on neural spine bifurcation until I had written the second post in that series (https://svpow.com/2012/04/05/neural-spinebifurcation-in-sauropods-what-we-knew-a-month-ago/)), but to write the paper as a series of blog posts, deliberately and from the outset, and get community feedback along the way. And I think that the sauropod neck mass project is perfect for that. Don’t expect this to become the most common topic of our posts, or even a frequent one. We still have to get those manuscripts done by the end of March, and we have no shortage of other projects waiting in the wings. And we’ll still post on goofy stuff, and on open access, and on sauropod stuff that has nothing to do with this–probably on that stuff a lot more often than on this. But every now and then there will be a post in this series, possibly written in my discretionary blogging time, that will hopefully move the paper along incrementally. References Alexander, R.M. 1985. Mechanics of posture and gait of some large dinosaurs. Zoological Journal of the Linnean Society, 83(1): 1-25. Alexander, R.M. 1989. Dynamics of Dinosaurs and Other Extinct Giants. Columbia University Press. Hutchinson, J.R., Bates, K.T., Molnar, J., Allen, V., and Makovicky, P.J. 2011. A computational analysis of limb and body dimensions in Tyrannosaurus rex with implications for locomotion, ontogeny, and growth. PLoS ONE 6(10): e26037. doi:10.1371/journal.pone.0026037 (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0026037) Taylor, M.P. 2009. A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29(3):787-806. (http://mygeologypage.ucdavis.edu/motani/pdf/Motani2001.pdf) Wedel, M.J., and Taylor, M.P. In press. Neural spine bifurcation in sauropod dinosaurs of the Morrison Formation: ontogenetic and phylogenetic implications. PalArch’s Journal of Vertebrate Paleontology. Witton, M.P., and Naish, D. 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS ONE 3(5): e2271. doi:10.1371/journal.pone.0002271 (10.1371/journal.pone.0002271) Posted by Matt Wedel Filed in brachiosaurids, Brachiosaurus, cervical, diplodocids, Diplodocus, mass estimates, necks, open access, opportunities, sauropod neck mass project 24 Comments »

The Recapture Creek sauropod: the reveal March 3, 2013

(https://svpow.files.wordpress.com/2013/02/recapture-creek-comparo-with-measurements.jpg)

If you’re just joining us, this post is a follow-up to this one (https://svpow.com/2013/02/28/how-big-was-the-recapture-creek-sauropod/), in which I considered the possible size and identity of the Recapture Creek femur fragment, which “Dinosaur Jim” Jensen (https://svpow.com/2011/06/01/how-big-was-brachiosauruss-forelimb/) (1987: page 604) said was “the largest bone I have ever seen”. True to his word, Brooks Britt at BYU got back to me with measurements of the Recapture Creek femur fragment in practically no time at all: Length 1035 mm, width 665 mm. However, you cannot trust the measurements because Jensen put a lot of plaster on the proximal half of the bone. Now, taking plaster off a bone is not going to make it any larger. So the plastered-up specimen is the best case scenario for the RC femur to represent a gigapod (https://svpow.com/2008/05/20/sv-pow-showdown-sauropods-vs-whales/). And I know the stated width of 665 mm is the max width of the proximal end, because I sent Brooks a diagram showing the measurements I was requesting. The length is a little less than anticipated, and doesn’t quite jibe with the max proximal width–I suspect a little might have broken off from the distal end where the preservation looks not-so-hot. Based on those measurements, it looks like Jensen got the scale bar in Figure 8 in his 1987 paper approximately right–if anything, the scale bar is a little undersized, but only by 5% or so, which is actually pretty good as these things go (https://svpow.com/2009/04/23/mydd/) (scale bars without measurements are still dag-nasty evil, though). By overlapping Jensen’s photo with the femur of the Brachiosaurus altithorax holotype (FMNH P25107) to estimate the size of the element when complete, I get a total length of 2.2 meters–exactly the same size as about 8% bigger than the Brachiosaurus holotype (actual length 2.03 m). If the Recapture Creek femur is from a Camarasaurus, which I don’t think we can rule out, it was 2 meters long when complete, or 11% longer and 37% more massive than the big C. supremus AMNH 5761–about 35 tonnes or maybe 40 on the outside. So it’s a big bone to be sure, but it doesn’t extend only slightly extends the known size range of Morrison sauropods. (Updated 2014-05-19–as I related in the first post, I somehow got it fixed in my head that the holotype B.a. femur was 2.19 m when it is actually 2.03 m.) So, as before, caveat estimator when working from scaled illustrations of single partial bones of possibly immense sauropods (https://svpow.com/2010/02/19/how-big-was-amphicoeliasfragillimus-i-mean-really/). Now, here’s a weird thing. Let’s assume for the sake of this discussion that the Recapture Creek femur is from a brachiosaur. That gives us three individual Late Jurassic brachiosaurids–the Recapture Creek animal, the Brachiosaurus altithorax holotype (https://svpow.com/2012/05/03/mold-a-rama/), and the mounted Giraffatitan brancai (https://svpow.com/2008/11/27/shedloads-of-awesome-part-1-the-humboldt-brachiosaur-remount/)–that are almost exactly the same size in limb bone dimensions (although B.a. had a longer torso (https://svpow.com/2009/09/20/what-a-23-longer-torso-looks-like/)). But we know that brachiosaurids got bigger, as evidenced by the XV2 specimen of Giraffatitan (https://svpow.com/2009/03/16/brachiosaurus-both-bigger-and-smaller-than-you-think-incomplete/), and based on the lack of scapulocoracoid fusion in both FMNH P25107 and the mounted Giraffatitan. So why do we keep finding these (and smaller) subadults, and so few that were XV2-sized? I know that there gets to be a preservation bias against immense animals (it’s hard to bury a 50-tonne animal all in one go (https://svpow.com/2008/07/24/the-enigmatic-taphonomy-of-sauroposeidon/)), but I would not think the 13% linear difference between these subadults and XV2-class adults would be enough to matter. Your thoughts? Reference Jensen, J.A. 1987. New brachiosaur material from the Late Jurassic of Utah and Colorado. Great Basin Naturalist 47(4): 592-608. (https://ojs.lib.byu.edu/wnan/index.php/wnan/article/viewFile/1849/2197) Posted by Matt Wedel Filed in brachiosaurids, Brachiosaurus, camarasaurs, femur, size, stinkin' appendicular elements 10 Comments »

How big was the Recapture Creek sauropod? February 28, 2013 From Jensen (1987, page 604): “In 1985 I found the proximal third of an extremely large sauropod femur (Figs. 8A, 12A) in a uranium miner’s front yard in southern Utah. The head of this femur is 1.67 m (5’6²) in circumference and was collected from the Recapture Creek Member of the the Morrison Formation in Utah near the Arizona border. It is the largest bone I have ever seen.” Jensen included not one but two figures of this immense shard of excellence. Here they are:

(https://svpow.files.wordpress.com/2013/02/jensen-1987-figure-8.jpg) Jensen 1987, Figure 8

(https://svpow.files.wordpress.com/2013/02/jensen-1987-fig-12.jpg) Jensen 1987, Figure 12 The specimen was heavily reconstructed, as you can see from the big wodge of unusually smooth and light-colored material in the photo. So we can’t put much stock in that part of the specimen. Unfortunately, the only measurement of the specimen that Jensen gives in the paper is that circumference; there are no straight-line linear measurements, and the figures both have the dreaded scale bars. Why dreaded? Check this out:

(https://svpow.files.wordpress.com/2013/02/recapture-creek-figs-8-and-12-compared.jpg)As you can see, when the scale bars are set to the same size, the bones are way off (the scale bar in the drawing is 50 cm). This is not an uncommon problem. (https://svpow.com/2009/04/23/mydd/) I make the Fig 8 version 30% bigger in max mediolateral width of the entire proximal end, and still 17% bigger in minimum diameter across the femoral head, as measured from the slight notch on the dorsal surface (on the right in this view). Can we figure out which is more accurate based on the internal evidence of the paper? For starters, the Fig 12 version is a drawing (1), that does not match the outline from the photo (2), and the hand-drawn scale bar (3) does not actually coincide with any landmarks (4), and that’s plenty of reasons for me not to trust it. What about that circumference Jensen mentioned? Unfortunately, he didn’t say exactly where he took it, just that the head of the femur had a circumference of 1.67 meters. Is that for the entire proximal end, or for the anatomical head that fits in the acetabulum, er wot? I’m afraid the one measurement given in the paper is no help in determining which of the figures is more accurately scaled. The obvious thing to do would be to see if this bone is in the BYU collections, and just measure the damn thing. More on that at the end of the post. In the meantime, Jensen said that the shape of the Recapture Creek femur was most similar to the femur of Alamosaurus, or to that of Brachiosaurus among Morrison taxa, and he referred it to Brachiosauridae. So how does this thing–in either version–compare with the complete femur of FMNH P25107, the holotype of Brachiosaurus altithorax?

(https://svpow.files.wordpress.com/2013/02/recapture-creek-boba-comparo.jpg) The Recapture Creek femur fragment compared to the complete femur of the Brachiosaurus altithorax holotype FMNH P25107 The first thing to notice is that the drawn outline from Figure 12 is a much better match for the Brachiosaurus altithorax femur–enough so that I wonder if Jensen drew it from the Recapture Creek specimen, or just traced the B.a. proximal femur and scaled it accordingly (or maybe not accordingly, since the scale bars don’t match). But let’s get down to business: how long would the complete femur have been? Using the scale bar in the photograph from Figure 8 (on the left in above image), I get a total femur length of 2.36 meters. Which is long, but only 7.7% longer than the 2.19-meter femur of FMNH P25107, and therefore only 25% more massive. So, 35 tonnes to Mike’s 28-tonne B.a., or maybe 45 tonnes to a more liberal 36-tonne B.a. Big, yeah, but not world-shattering. Update 2014-05-19: I don’t know where I got the 2.19-meter femur length for Brachiosaurus altithorax, but it’s a mistake. So the rest of that paragraph should read: Which is 16% longer than 2.03-meter femur of FMNH P25107, and therefore 57% more massive. So, 44 tonnes to Mike’s 28-tonne B.a., or maybe 57 tonnes to a more liberal 36-tonne B.a. That’s nowhere near the 2.5-meter femur and estimated 70-tonne mass of the largest Argentinosaurus, but it’s pretty darned good for a brachiosaur. Using the scale bar in the drawing from Figure 12 (on the right in the above image)–which, remember, is 50 cm, not 1 meter–I get a total femur length of about 1.9 meters, which is considerably smaller than the B.a. holotype. That is very much at odds with Jensen’s description of it as “the largest bone I have ever seen”, and given that we have many reasons for not trusting the scale bar in the drawing, it is tempting to just throw it out as erroneous. So it would seem that unless Jensen got both scale bars too big, the Recapture Creek brachiosaur was at most only a shade bigger than the holotype specimen of Brachiosaurus altithorax. But wait–is the Recapture Creek brachiosaur a brachiosaur at all? Jensen didn’t list any characters that pushed him toward a brachiosaurid ID, and I don’t know of any proximal femur characters preserved in the specimen that would separate Brachiosaurus from, say, Camarasaurus. And in fact a camarasaur ID has a lot to recommend it, in that Camarasaurus femora have very offset heads (the ball- or cylinder-like articular surface at the top end sticks out a big more to engage with the hip socket–see Figure 12 up near the top of the post), moreso than in many other Morrison sauropods, and that would make them better matches for the Recapture Creek femur photo. Here’s what the comparo looks like:

(https://svpow.files.wordpress.com/2013/02/recapture-creek-camarasaurus-comparo.jpg) The Recapture Creek femur fragment compared with a complete femur of Camarasaurus. I make that a 2.07-meter femur using the photo on the left, and a 1.66-meter femur using the drawing on the right. The one decent femur in the AMNH 5761 Camarasaurus supremus collection is 1.8 meters long, so these results are surprisingly similar to those for the B. althithorax comparison–the drawing gives a femur length shorter than the largest known specimens, and the photo gives a length only slightly longer. A camarasaur with a 2.07 meter femur would be 15% larger than the AMNH C. supremus in linear terms, and assuming isometric scaling, 1.5 times as massive–maybe 38 tonnes to AMNH 5761’s estimated 25. A big sauropod to be sure, but not as big as the largest apatosaurs (https://svpow.com/2012/04/25/the-giant-oklahomaapatosaurus-omnh-1670/), and not nearly as big as the largest titanosaurs. I have always been surprised that the Recapture Creek femur frag has attracted so little attention, given that “Dinosaur Jim” himself called it the biggest bone he had ever seen. But it appears that the lack of attention is justified–whether it was a brachiosaur or a camarasaur, and using the most liberal estimates the scale bars allow, it simply wasn’t that big. Update about half an hour later: Okay, maybe I was a little harsh here. IF the photo scale bar is right, the Recapture Creek femur might still represent the largest and most massive macronarian from the Morrison Formation (Edit: only if it’s a brachiosaur and not a camarasaur; see this comment (https://svpow.com/2013/02/28/how-big-was-the-recapture-creeksauropod/#comment-28212)), which is something. I suppose I was particularly underwhelmed because I was expecting something up in OMNH 1670 (https://svpow.com/2012/04/25/thegiant-oklahoma-apatosaurus-omnh-1670/)-to-Argentinosaurus territory, and so far, this ain’t it. I’ll be interested to see what the actual measurements say (read on). The Moral of This Story So, if it wasn’t that big after all, and if no-one has made a stink about it being big before now, why go to all this trouble? Well, mostly just to satisfy my own curiosity. If there was a truly gigantic brachiosaur from the Morrison, it would be relevant to my interests, and it was past time I crunched the numbers to find out. But along the way something occurred to me: this should be a cautionary tale for anyone who gets all wound up about the possible max size of Amphicoelias fragillimus (https://svpow.com/2010/02/19/how-big-was-amphicoelias-fragillimus-i-mean-really/). As with A. fragillimus, for the Recapture Creek critter we have part of one bone, and at least for this exercise I was working only from published illustrations with scale bars. And as with A. fragillimus, the choice of a reference taxon is not obvious, and the size estimates are all over the place, and some of them just aren’t that big.

It always amuses me when A. fragillimus comes up and people (well, trolls (https://svpow.com/2010/02/19/how-big-was-amphicoelias-fragillimus-i-mean-really/#comment-27932)) accuse us of being big ole’ wet blankets (https://svpow.com/2010/02/19/how-big-was-amphicoelias-fragillimus-i-mean-really/#comment-27320) that just don’t want to believe in 200-tonne sauropods. It amuses me because it’s wrong on so many levels. Believe me, when we have our sauropod fanboy hats on, we most definitely do want to believe in 200-tonne sauropods (https://svpow.com/2010/02/19/how-big-was-amphicoelias-fragillimus-i-mean-really/#comment-27470). That would rock. But when we put our scientist hats on, wanting and belief go right out the window. We have to take a cold, hard look at the data, and especially at its limitations. Oh, the other moral is to go buy a tape measure, and use it (https://svpow.com/2009/04/23/mydd/). Sheesh! Coda As I said above, the obvious thing to do would be to just track down the bone and measure it. It does still exist, it’s in the BYU collections, and Brooks Britt has kindly offered to send along some measurements when he gets time. So we should have some real answers before long (and here they are (https://svpow.com/2013/03/03/the-recapture-creek-sauropod-the-reveal/)). But I wanted to work through this example without them, to illustrate how much uncertainty creeps in when trying to estimate the size of a big sauropod from published images of a single partial bone. Reference Jensen, J.A. 1987. What I did on my holidaysNew brachiosaur material from the Late Jurassic of Utah and Colorado. Great Basin Naturalist 47(4): 592-608. (https://ojs.lib.byu.edu/wnan/index.php/wnan/article/viewFile/1849/2197) Posted by Matt Wedel Filed in Amphicoelias, brachiosaurids, Brachiosaurus, camarasaurs, femur, size, stinkin' appendicular elements 4 Comments »

Oblivious sauropods being eaten January 14, 2013

(https://svpow.files.wordpress.com/2013/01/being-eaten-600.jpg) My friend, colleague, and sometime coauthor (https://svpow.com/papers-by-sv-powsketeers/taylor-hone-wedel-and-naish-2011-on-sexual-selection-of-sauropod-necks/) Dave Hone sent the above cartoon, knowing about my more-than-passing interest (https://svpow.com/2011/05/23/the-worlds-longest-cells-speculations-on-the-nervous-systems-of-sauropods/) in sauropod neurology. It was drawn by Ed McLachlan in the early 1980s for Punch! magazine in the UK (you can buy prints starting at £18.99 here (http://punch.photoshelter.com/image/I000005x.Ed0EtoM)). I know that this isn’t the only image in the “oblivious sauropods getting eaten” genre. There’s a satirical drawing in Bakker’s The Dinosaur Heresies showing a sleeping brontosaur getting its tail gnawed on by some pesky mammals. I’ll scan that and post it when I get time (Update: I did (https://svpow.com/2013/05/07/oblivious-sauropods-being-eaten-part-2-bakkers-snoozingbrontosaur/)). I’m sure there must be others in a similar vein–point me to them in the comments or email me and I’ll post as many as I can get my hands on. I wouldn’t post stuff like this if I didn’t think it was funny. But if you want the real scoop on whether sauropods could have responded quickly to injuries to their distant extremities, here’s the deal: First of all, sauropods really did have individual sensory nerve cells that ran from their extremities (tip of tail, soles of feet)–and from the rest of their skin–to their brainstems. In the longest sauropods, these cells were probably something like 150 feet long, and may have been the longest cells in the history of life. We haven’t found any fossils of these nerves and almost certainly never will, but we can be sure that sauropods had them because all vertebrates do, from hagfish on up. That’s just how we’re built. (This is all rehash for regular readers–see this post (https://svpow.com/2011/05/23/the-worlds-longest-cells-speculations-on-the-nervous-systems-of-sauropods/) and the linked paper.)

(https://svpow.files.wordpress.com/2011/05/wedel-rln-fig2-480.jpg) So how long does it take to send a nerve impulse 150 feet? The fastest nerve conduction velocities are in the neighborhood of 120 meters per second, so a signal from the very tip of the tail in a 150-foot sauropod would take about half a second to reach the brain. Is it possible that sauropods had accelerated nerve conduction velocities, to bring in those distant signals faster? To the brain, probably not. The only ways to speed up a nerve impulse are to increase the diameter of the axon itself, which some invertebrates do, and to increase the thickness of the myelin sheath around the axon, which is what vertebrates tend to do (some invertebrates have myelin-like tissues that apparently help accelerate their nerve impulses, too). Fatter axons mean fatter nerves, and for at least half the trip to the brain, the axons in question are part of the spinal cord. And we know that sauropod spinal cords were pretty small, relative to their body size, because the neural canals of their vertebrae, through which their spinal cords passed, are themselves small–Hatcher wrote about this more than a century ago. So there’s a tradeoff–sauropods could have had very fast, very fat axons, but not very many of them, and therefore poor “coverage” at their extremities, with nerve endings widely spaced, or better coverage with more axons, but those axons would be skinnier and therefore slower. We don’t know which way they went.

Incidentally, you can experiment with the density of sensory nerve endings in your own body. Close your eyes or blindfold yourself, and have a friend poke you in various places with chopsticks. Seriously–start with the two chopsticks right together, and gradually spread them out until you can feel two distinct points (or, if you want to get really tricky, have your friend mix up the close and widely spread touches so there’s no direction for you to anticipate). The least sensitive part of your body is your back–over your back and shoulders, you’ll probably have a hard time distinguishing points of touch that are less than an inch apart. On your hands and face, you’ll probably be able to distinguish points only a few millimeters apart; in fact, for fingertips you’ll probably need finer instruments than chopsticks–maybe toothpicks or pins, but I take no responsibility for any accidental acupuncture! Back to sauropods. Could predators have taken advantage of the comparatively long nerve conduction velocities in sauropods? I seriously doubt it, for several reasons:

Simple reflex arcs are governed by interneurons in the spinal cord. The tail-tip-to-spinal-cord distance was a lot shorter than the tail-tip-to-brain route. Even over the round trip of “sensory impulse in, motor impulse out”, it would have been at worst equal, and that’s assuming the nerve impulse had to go all the way to the base of the tail.* Call it half a second, max. It gets worse: the peripheral nerves outside the spinal cord are not limited by the size of the neural canal, so they can be more heavily myelinated, with faster conduction times. For example, each of the sciatic nerves running down the backs of your thighs is much larger in cross-section than your entire spinal cord. If sauropod peripheral nerves were selected for fast conduction, they might have been bigger and faster than anything around today. Half a second is not much time for a theropod to formulate a plan, especially if Step 1 of the plan is “grab 150-foot sauropod by the tail”. This assumes that said theropod was able to sneak right up to the sauropod without being detected. You go try that with a big wild herbivore and let me know how it works out. (Also, a big animal tolerating your presence, because you are pathetically small and weak, is not the same as it being unaware of your presence.) All of this assumes the theropod only went for the bony whip-lash at the tip of the tail–the fastest-moving extremity, and the least-nourishing single bite anywhere on the target. If the theropod went for a meatier bite closer to the base of the tail, it would have to sneak closer to the sauropod’s head (better chance of being spotted), and the nerve conduction delay would be shortened. A 150-foot sauropod would probably mass somewhere between 50 and 100 tons, and would be capable of dealing incredible damage to even the largest theropods, which maxed out around 15 tons. There’s a good reason predators go after the young, sick, and weak. Smaller sauropods would be less dangerous, but they’d also have faster tail-to-central-nervous-systemand-back reaction times. A theropod big enough to go after a 150-foot sauropod would also be subject to fairly long nerve-conduction delays, which would limit whatever trifling advantage it might have gotten from such delays in the sauropod. So, although I have no doubt that in their long history together, giant theropods did occasionally tackle full-grown giant sauropods–because real animals do all kinds of weird things if you watch them long enough (https://svpow.com/2011/11/28/accurate-vs-familiar-vs-usual-in-paleoart/), and lions will take on elephants when they get desperate–I am extremely skeptical that the theropods enjoyed any advantage based on the “slow” nervous systems of those sauropods.

(https://svpow.files.wordpress.com/2013/01/spinal-cord-human-organs.jpg) Borrowed from http://humanorgans.org/spinal-cord/ (http://humanorgans.org/spinal-cord/)

* Some relevant hard-core anatomy for the curious: sauropods have neural canals in their tail vertebrae, and usually far down their tails, too. But that doesn’t mean much–you have neural canals to the bottom half of your sacrum, but your spinal cord stops around your first or second lumbar vertebra. From there on down, you just have nerve roots. So the shortest reflex arc from your big toe has to go up to your lower back and return. Why is your spinal cord so short? Basically because your central nervous system stops growing when you’re still a child–it will add new connections after that, and a few new cells in your olfactory bulbs and hippocampus, but it won’t get appreciably bigger or longer. After mid-childhood, your body keeps growing but your spinal cord stays the same length, so you end up with this freaky little-kid spinal cord tucked up inside your grown-up vertebral column. Weird, huh?

So did sauropod spinal cords stop at mid-back or go all the way into the tail? We have several conflicting lines of evidence. In extant reptiles, the spinal cord does extend into the tail in at least some taxa (I haven’t done anything like a complete survey, just read a couple of papers). Birds are no help because their tails are extremely short, but their spinal cords do extend into the synsacrum (and expand there, thanks to the glycogen body, which was probably also present in sauropods and responsible for the inaccurate “second brain” meme (https://svpow.com/2009/12/15/lies-damned-lies-and-clash-of-the-dinosaurs/)). But then birds grow up very fast, with even the largest reaching full size in a year or two, so they don’t share our problem of the body outgrowing the nervous system. We know that sauropods grew pretty quickly, but they also took a while to mature–somewhere between one and three decades, probably. Did that protracted growth period give their vertebral columns the time to outgrow their spinal cords? I have no idea, because the division of the spinal cord into roots happens inside the dura mater and doesn’t leave any skeletal traces that I know of. Someone should go figure it out–or at least figure out if it can be figured out! Posted by Matt Wedel Filed in Art, goofy, nervous system, oblivious sauropods being eaten, predation, stinkin' mammals, stinkin' ornithischians, stinkin' theropods, Tails 15 Comments »

Welcome Kaatedocus: this is how to illustrate a sauropod December 20, 2012 A couple of days ago, a paper by Tschopp and Mateus (2012) described and named a new diplodocine from the Morrison Formation, Kaatedocus siberi, based on a beautifully preserved specimen consisting of a complete skull and the first fourteen cervical vertebrae. Unfortunately, the authors chose to publish their work in the Journal of Systematic Palaeontology, a paywalled journal, which means that most of you reading this will be unable to read the actual paper — at least, not unless you care enough to pay £27 for the privilege. So you’ll just have to take my word for it when I tell you that it’s a fine, detailed piece of work, weighing in at 36 pages. It features lavish illustrations of the skull, but we won’t trouble you with those. The vertebrae are illustrated rather less comprehensively, though still better than in most papers:

(https://svpow.files.wordpress.com/2012/12/tschoppmateus2012-new-morrison-flagellicaudatan-kaatedocusfig9.jpeg) Tschopp and Matteus (2012: figure 9). A, Photograph and B, drawings of the mid-cervical vertebrae of the holotype of Kaatedocus siberi (SMA 0004). Photograph in lateral view and to scale, CV 8 shown in the drawings is indicated by an asterisk. Drawings of CV 8 (B) in dorsal (1), lateral (2), ventral (3), posterior (4) and anterior (5) views. Scale bars = 4 cm. It should be immediately apparent from these lateral views that the vertebra are rather Diplodocus-like. But the hot news is that there is a great raft of free supplementary information (http://www.tandfonline.com/doi/suppl/10.1080/14772019.2012.746589#tabModule), including full five-orthogonal-view photos of all fourteen vertebrae! Here is just one of them, C6, in glorious high resolution (click through for the full awesome):

(https://svpow.files.wordpress.com/2012/12/tjsp_a_746589_sup_30911353.jpeg) Now, folks, that is how to illustrate a sauropod in 2012! The goal of a good descriptive paper is to be the closest thing possible to a proxy for the specimen itself, and you just can’t do that if you don’t illustrate every element from multiple directions. By getting this so spectacularly right, Tschopp and Matteus have made their paper the best illustrated sauropod description for 91 years. (Yes, I am talking about Osborn and Mook 1921.) It’s just a shame that all the awe-inspiring illustrations are tucked away in supplementary information rather than in the paper itself. Had the paper been published in a PLOS journal, for example, all the goodness could have been in one place, and it would all have been open access.

Is Kaatedocus valid? There’s a bit of a fashion these days for drive-by synonymisation (https://svpow.com/2012/04/12/neural-spine-bifurcation-in-sauropods-part-4-is-suuwassea-a-juvenile-of-a-knowndiplodocid/) of dinosaurs, and sure enough no sooner had Brian Switek written about Kaatedocus (http://phenomena.nationalgeographic.com/2012/12/18/jurassic-boneyard-yields-hiddendinosaur/) for his new National Geographic blog than comments started cropping up arguing (or in some cases just stating) that Kaatedocus is merely Barosaurus. It’s not. I spent a lot of time with true Barosaurus cervicals at Yale this summer, and those of Kaatedocus are nothing like them. Here is Tschopp and Mateus’s supplementary figure of C14:

(https://svpow.files.wordpress.com/2012/12/tjsp_a_746589_sup_30912152.jpeg) And here is a posterior vertebra — possibly also C14 — of the Barosaurus holotype YPM 429, in dorsal and right lateral views:

(https://svpow.files.wordpress.com/2012/12/img_0441.jpg)

(https://svpow.files.wordpress.com/2012/12/img_0430.jpg) Even allowing for a certain amount of post-mortem distortion and “creative” restoration, it should be immediately apparent that (A) Barosaurus is much weirder than most people realise, and (B) Kaatedocus ain’t it. There may be more of a case to be made that Kaatedocus is Diplodocus — but that’s the point: it there’s a case, then it needs to be actually made, which means a point-by-point response to the diagnostic characters proposed by the authors in their careful, detailed study based on months of work with the actual specimens. There seems to be an idea abroad at the moment that it’s somehow more conservative or sober or scientific to assume everything is a ontogenomorph of everything else — possibly catalysed by the Horner lab’s ongoing “Toroceratops” initiative (http://blogs.smithsonianmag.com/dinosaur/2011/01/the-great-triceratops-debate-continues/) and subsequent cavalier treatment (https://svpow.com/2012/04/14/neural-spine-bifurcation-in-sauropods-part-5-is-haplocanthosaurus-a-juvenile-of-a-known-diplodocid/) of Morrison sauropods — maybe even by the Amphidocobrontowaassea paper (https://svpow.com/2010/10/07/the-elephant-in-the-living-room-amphicoelias-brontodiplodocus/). Folks, there is no intrinsic merit in assuming less diversity. Historically, the Victorian sauropod palaeontologists of England did at least as much taxonomic damage by assumptions of synonymy (everything’s Cetiosaurus or Ornithopsis — whatever that is (https://svpow.com/2007/12/30/and-a-happy-new-year-lamest-type-specimen-ever/)) as they did by raising new taxa. The thing to do is find the hypothesis best supported by evidence, not presupposing that either splitting or lumping is a priori the more virtuous course. Sermon ends.

Morrison sauropod diversity As we’ve pointed out (http://www.miketaylor.org.uk/dino/pubs/taylor2006/Taylor2006-dinosaur-diversity.pdf) a few times (http://www.miketaylor.org.uk/dino/pubs/taylor-et-al2011/TaylorEtAl2011-brontomerus.pdf) in our published work, sauropod diversity in the Kimmeridgian-Tithonian in general, and in the Morrison Formation in particular, was off-the-scale crazy. There’s good evidence for at least a dozen sauropod genera in the Morrison, and more than fifteen species. Kaatedocus extends this record yet further, giving us a picture of an amazing ecosystem positively abundant with numerous species of giant animals bigger than anything alive on land today. Sometimes you’ll hear people use this observation as a working-backwards piece of evidence that Morrison sauropods are oversplit. Nuh-uh. We have to assess taxonomy on its own grounds, then see what it tells us about ecosystem. As Dave Hone’s new paper affirms (http://www.guardian.co.uk/science/lost-worlds/2012/dec/19/dinosaurs-fossils) (among many others), Mesozoic ecosystem were not like modern ones. We have to resist the insidious temptation to assume that what we would have seen in the Late Jurassic is somehow analogous to what we see today on the Serengeti. Hutton’s (or Lyell’s) idea that “the present is the key to the past (https://en.wikipedia.org/wiki/Uniformitarianism)” may be helpful in geology. But despite its roots as a branch of the discipline, the palaeontology we do today is not geology. When we’re thinking about ancient ecosystems, we’re talking about palaeobiology, and in that field the idea that the present is the key to the past is at best unhelpful, at worst positively misleading. Sermon ends.

But isn’t the Kaatedocus holotype privately owned? You’ve had two sermons already, I’m sure we can all agree that’s plenty for one blog post. I will return to this subject in a subsequent post. Sermon doesn’t even get started.

References Osborn, Henry Fairfield, and Charles C. Mook. 1921. Camarasaurus, Amphicoelias and other sauropods of Cope. Memoirs of the American Museum of Natural History, n.s. 3:247-387, and plates LX-LXXXV. (http://digitallibrary.amnh.org/dspace/handle/2246/5724) Tschopp, Emanuel, and Octávio Mateus. 2012. The skull and neck of a new flagellicaudatan sauropod from the Morrison Formation and its implication for the evolution and ontogeny of diplodocid dinosaurs. Journal of Systematic Palaeontology. doi:10.1080/14772019.2012.746589 (http://www.tandfonline.com/doi/abs/10.1080/14772019.2012.746589) Posted by Mike Taylor Filed in Barosaurus, cervical, diplodocids, Kaatedocus, paleobiology, rants 18 Comments »

Un sauropode aux jambes musclées November 12, 2012 Alexandre Fabre recently bought a French-language comic-book, Les Dinosaures (http://www.lesdinosaures.net/blog/) by Plumeri and Bloz, and found this in the third volume:

(https://svpow.files.wordpress.com/2012/11/brontomerus.jpeg) The text reads: Et parfois, les paléontologues font des announces très marrantes, comme le Brontomerus … … un sauropode aux jambes musclées … qui se défendrait en donnant des coups de pied! “Aie! Un dino qui fait de kung-fu? Ils ne savent plus quoi inventer!” Which I roughly translate as: And sometimes, paleontologists make very funny announcements, such, as Brontomerus … A sauropod with muscular legs … which defends itself by kicking! “Ouch! A dino that does kung-fu? Whatever will they think of next!” Many thanks to Alexandre for bringing it to my attention and scanning the relevant panels. Posted by Mike Taylor Filed in Art, Brontomerus Leave a Comment »

Taylor and Wedel (2013a) on sauropod neck anatomy September 26, 2012

The paper Taylor, Michael P., and Mathew J. Wedel. 2013. Why sauropods had long necks; and why giraffes have short necks. PeerJ 1:e36 (https://peerj.com/articles/36/). 41 pages, 11 figures, 3 tables. doi:10.7717/peerj.36

Preprint on arXiv Before this paper was published in PeerJ, we posted a preprint on arXiv, a service that is used ubiquitously in maths, physics and astronomy, but less often in biology. (The existence of this preprint in 2012 is why the URL of this page has that year in it.) The reference for the preprint is: Taylor, Michael P., and Mathew J. Wedel. 2012. Why sauropods had long necks; and why giraffes have short necks. arXiv:1209.5439 (http://arxiv.org/abs/1209.5439). 39 pages, 11 figures, 3 tables.

SV-POW! posts The first three of these were posted when the arXiv preprint was the only publicly available version. The remainder were posted after publication in PeerJ. Why giraffes have short necks (https://svpow.com/2012/09/26/why-giraffes-have-short-necks/) Posting palaeo papers on arXiv (https://svpow.com/2012/09/28/posting-palaeo-papers-on-arxiv/) Mammals have short necks because of local maxima (https://svpow.com/2012/09/30/mammals-have-short-necks-because-of-local-maxima/) PeerJ launches today! (and we’re in it!) (https://svpow.com/2013/02/12/peerj-launches-today-and-were-in-it/) Terrifying hypothetical cervical vertebrae of the Morrison Formation (https://svpow.com/2013/02/13/terrifying-hypothetical-cervical-vertebrae-of-the-morrison-formation/) (and see also Terrifying actual cervical vertebrae of the Morrison Formation (https://svpow.com/2013/02/17/terrifying-actual-cervical-vertebrae-of-the-morrison-formation/)) Open peer-review at PeerJ (https://svpow.com/2013/02/14/open-peer-review-at-peerj/) Personal milestones: publishing the Ph.D (https://svpow.com/2013/02/19/personal-milestones-publishing-the-ph-d/) How disruptive is PeerJ? (https://svpow.com/2013/02/21/how-disruptive-is-peerj/) Get your relative-lengths-of-sauropod-necks T-shirts! (https://svpow.com/2014/03/17/get-your-relative-lengths-of-sauropod-necks-t-shirts/)

Elsewhere on the Web Why don’t giraffes have necks as long as a Brachiosaurus? (http://boingboing.net/2012/09/27/why-dont-giraffes-have-necks.html) [BoingBoing] PeerJ leads a high-quality, low-cost new breed of open-access publisher (http://www.guardian.co.uk/science/blog/2013/feb/12/peerj-open-access-academic-publisher) [Guardian; by Mike] PeerJ and Why Giraffes Have Short Necks (http://haicontroversies.blogspot.co.uk/2013/02/peerj-and-why-giraffes-have-short-necks.html) How PeerJ Is Changing Everything In Academic Publishing (http://www.techdirt.com/articles/20130210/14302221939/how-peerj-is-changing-everything-academicpublishing.shtml) [TechDirt; by Mike] PeerJ (http://shinka3.exblog.jp/19264263/) [in Japanese: “Starting PeerJ”] (Google translation (http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF8&eotf=1&u=http%3A%2F%2Fshinka3.exblog.jp%2F19264263%2F&act=url)) Why a dinosaur neck dominates the front of PeerJ for our first “issue” (http://blog.peerj.com/post/43069053645/why-a-dinosaur-neck-dominates-the-front-of-peerj-for) [PeerJ blog] El cuello de 15 metros del Supersaurus (http://www.dinoastur.com/2013/02/14/cuello-supersaurus/) [DinoAstur. In Spanish: “The 15-meter neck of Supersaurus“] (Google translation (http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&eotf=1&u=http%3A%2F%2Fwww.dinoastur.com%2F2013%2F02%2F14%2Fcuellosupersaurus%2F&act=url)) How Dinosaurs Grew the World’s Longest Necks (http://www.livescience.com/27376-how-dinosaurs-grew-longest-necks.html?cid=dlvr.it) [Live Science] Dinosaur Reproduction, Not Ancient Gravity, Allowed Super-Sized Sauropods to Evolve (http://phenomena.nationalgeographic.com/2013/02/25/dinosaur-reproduction-not-ancientgravity-made-sauropods-super-sized/) [Laelaps at National Geographic] New Theory Tries To Explain Why Dinosaurs Grew So Huge — Especially Their Amazing Necks (http://www.geekosystem.com/how-dinosaurs-got-so-big/) [Geekosystem] Los largos cuellos de algunos dinosaurios se explicarían por sus huesos huecos (http://www.latercera.com/noticia/tendencias/2013/02/659-510625-9-los-largos-cuellos-de-algunosdinosaurios-se-explicarian-por-sus-huesos-huecos.shtml) [Tendencias. In Spanish: “The long necks of some dinosaurs are explained by their hollow bones”] (Google translation (http://translate.google.co.uk/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF8&eotf=1&u=http%3A%2F%2Fwww.latercera.com%2Fnoticia%2Ftendencias%2F2013%2F02%2F659-510625-9-los-largos-cuellos-de-algunos-dinosaurios-se-explicarian-por-sushuesos-huecos.shtml)) Giraffes Have Short Necks Compared to Sauropods. Learn Why and How. (http://tumblehometalks.com/2013/02/26/giraffes-have-short-necks-compared-to-sauropods-learn-why-andhow/) [Tumblehome Talks]

High-resolution figures The following high-resolution versions of the figures from the paper are for the benefit of scientists and reporters. Feel free to reproduce or modify these (with attribution) for use in scientific scholarly literature and elsewhere.

(https://svpow.files.wordpress.com/2012/09/fig1-non-sauropod-neck-composite1.jpeg) Figure 1. Necks of long-necked non-sauropods, to scale. The giraffe and Paraceratherium are the longest necked mammals; the ostrich is the longest necked extant bird; Therizinosaurus and Gigantoraptor are the largest representatives of two long-necked theropod clades; Arambourgiania is the longest necked pterosaur; and Tanystropheus has a uniquely long neck relative to torso length. Human head modified from Gray’s Anatomy (1918 edition, fig. 602). Giraffe modified from photograph by Kevin Ryder (CC BY, http://flic.kr/p/cRvCcQ (http://flic.kr/p/cRvCcQ)). Ostrich modified from photograph by “kei51” (CC BY, http://flic.kr/p/cowoYW (http://flic.kr/p/cowoYW)). Paraceratherium modified from Osborn (1923, figure 1). Therizinosaurus modified from Nothronychus reconstruction by Scott Hartman. Gigantoraptor modified from Heyuannia reconstruction by Scott Hartman. Arambourgiania modified from Zhejiangopterus reconstruction by Witton & Naish (2008, figure 1). Tanystropheus modified from reconstruction by David Peters. Alternating blue and pink bars are 1 m tall.

(https://svpow.files.wordpress.com/2012/09/fig2-skeletons-of-non-sauropods1.jpeg) Figure 2. Full skeletal reconstructions of selected long-necked non-sauropods, to scale. 1, Paraceratherium. 2, Therizinosaurus. 3, Gigantoraptor. 4, Elasmosaurus. 5, Tanystropheus. Elasmosaurus modified from Cope (1870, plate II, figure 1). Other image sources as for Fig. 1. Scale bar = 2 m.

(https://svpow.files.wordpress.com/2012/09/fig3-sauropod-neck-composite1.jpeg) Figure 3. Necks of long-necked sauropods, to scale. Diplodocus, modified from elements in Hatcher (1901, plate 3), represents a “typical” long-necked sauropod, familiar from many mounted skeletons in museums. Puertasaurus, Sauroposeidon, Mamenchisaurus and Supersaurus modified from Scott Hartman’s reconstructions of Futalognkosaurus, Cedarosaurus, Mamenchisaurus and Supersaurus respectively. Alternating pink and blue bars are one meter in width. Inset shows Fig. 1 to the same scale.

(https://svpow.files.wordpress.com/2012/09/fig4-wedel2003-fig2-ostrich-neck-cross-section-composite.jpeg) Figure 4. Extent of soft tissue on ostrich and sauropod necks. 1, ostrich neck in cross section from Wedel (2003, figure 2). Bone is white, air-spaces are black, and soft tissue is grey. 2, hypothetical sauropod neck with similarly proportioned soft-tissue. (Diplodocusvertebra silhouette modified from Paul 1997, figure 4A). The extent of soft tissue depicted greatly exceeds that shown in any published life restoration of a sauropod, and is unrealistic. 3, More realistic sauropod neck. It is not that the soft-tissue is reduced but that the vertebra within is enlarged, and mass is reduced by extensive pneumaticity in both the bone and the soft-tissue.

(https://svpow.files.wordpress.com/2012/09/fig5-wedelsanders-myology.jpeg) Figure 5. Simplified myology of that sauropod neck, in left lateral view, based primarily on homology with birds, modified from Wedel and Sanders (2002, figure 2). Dashed arrows indicate muscle passing medially behind bone. A, B. Muscles inserting on the epipophyses, shown in red. C, D, E. Muscles inserting on the cervical ribs, shown in green. F, G. Muscles inserting on the neural spine, shown in blue. H. Muscles inserting on the ansa costotransversaria (“cervical rib loop”), shown in brown. Specifically: A. M. longus colli dorsalis. B. M. cervicalis ascendens. C. M. flexor colli lateralis. D. M. flexor colli medialis. E. M. longus colli ventralis. In birds, this muscle originates from the processes carotici, which are absent in the vertebrae of sauropods. F. Mm. intercristales. G. Mm. interspinales. H. Mm. intertransversarii. Vertebrae modified from Gilmore (1936, plate 24).

(https://svpow.files.wordpress.com/2012/09/fig6-archosaur-cervicals.jpeg) Figure 6. Basic cervical vertebral architecture in archosaurs, in posterior and lateral views. 1, seventh cervical vertebra of a turkey, Meleagris gallopavo Linnaeus, 1758, traced from photographs by MPT. 2, fifth cervical vertebra of the abelisaurid theropod Majungasaurus crenatissimus Depéret, 1896,UA 8678, traced from O’Connor (2007, figures 8 and 20). In these taxa, the epipophyses and cervical ribs are aligned with the expected vectors of muscular forces. The epipophyses are both larger and taller than the neural spine, as expected based on their mechanical importance. The posterior surface of the neurapophysis is covered by a large rugosity, which is interpreted as an interspinous ligament scar like that of birds (O’Connor, 2007). Because this scar covers the entire posterior surface of the neurapophysis, it leaves little room for muscle attachments to the spine. 3, fifth cervical vertebra of Alligator mississippiensis Daudin, 1801, MCZ 81457, traced from 3D scans by Leon Claessens, courtesy of MCZ. Epipophyses are absent. 4, eighth cervical vertebra of Giraffatitan brancai(Janensch, 1914) paralectotype HMN SII, traced from Janensch (1950, figures 43 and 46). Abbreviations: cr, cervical rib; e, epipophysis; ns, neural spine; poz, postzygapophysis.

(https://svpow.files.wordpress.com/2012/09/fig7-freak-gallery.jpeg) Figure 7. Disparity of sauropod cervical vertebrae. 1, Apatosaurus “laticollis” Marsh, 1879b holotype YPM 1861, cervical ?13, now referred to Apatosaurus ajax (see McIntosh, 1995), in posterior and left lateral views, after Ostrom and McIntosh (1966, plate 15); the portion reconstructed in plaster (Barbour, 1890, figure 1) is grayed out in posterior view; lateral view reconstructed after Apatosaurus louisae Gilmore, 1936 (Gilmore, 1936, plate XXIV). 2, “Brontosaurus excelsus” Marsh, 1879a holotype YPM 1980, cervical 8, now referred to Apatosaurus excelsus (see Riggs, 1903), in anterior and left lateral views, after Ostrom and McIntosh (1966, plate 12); lateral view reconstructed after Apatosaurus louisae (Gilmore, 1936, plate XXIV). 3, “Titanosaurus” colberti Jain and Bandyopadhyay, 1997 holotype ISIR 335/2, mid-cervical vertebra, now referred to Isisaurus (See Wilson and Upchurch, 2003), in posterior and left lateral views, after Jain and Bandyopadhyay (1997, figure 4). 4, “Brachiosaurus” brancai paralectotype HMN SII, cervical 8, now referred to Giraffatitan (see Taylor, 2009), in posterior and left lateral views, modified from Janensch (1950, figures 43–46). 5, Erketu ellisoniholotype IGM 100/1803, cervical 4 in anterior and left lateral views, modified from Ksepka and Norell (2006, figures 5a–d).

(https://svpow.files.wordpress.com/2012/09/fig8-neurapophyseal-spurs.jpeg) Figure 8. Sauropod cervical vertebrae showing anteriorly and posteriorly directed spurs projecting from neurapophyses. 1, cervical 5 of Sauroposeidon holotype OMNH 53062 in right lateral view, photograph by MJW. 2, cervical 9 of Mamenchisaurus hochuanensis holotype CCG V 20401 in left lateral view, reversed, from photograph by MPT. 3, cervical 7 or 8 of Omeisaurus junghsiensisYoung, 1939 holotype in right lateral view, after Young (1939, figure 2). (No specimen number was assigned to this material, which has since been lost. D. W. E. Hone personal communication, 2008.)

(https://svpow.files.wordpress.com/2012/09/fig9-interspinal-features.jpeg) Figure 9. Bifid presacral vertebrae of sauropods showing ligament scars and pneumatic foramina in the intermetapophyseal trough. 1, Apatosaurus sp. cervical vertebra OMNH 01341 in right posterodorsolateral view, photograph by MJW. 2, Camarasaurussp. dorsal vertebrae CM 584 in dorsal view, photograph by MJW. Abbreviations: las, ligament attachment site; pfa, pneumatic fossa; pfo, pneumatic foramen.

(https://svpow.files.wordpress.com/2012/09/fig10-hypothetical-euhelopus.jpeg) Figure 10. Real and speculative muscle attachments in sauropod cervical vertebrae. 1, the second through seventeenth cervical vertebrae of Euhelopus zdanskyi Wiman, 1929 cotype specimen PMU R233a-(“Exemplar a”). 2, cervical 14 as it actually exists, with prominent but very short epipophyses and long cervical ribs. 3, cervical 14 as it would appear with short cervical ribs. The long ventral neck muscles would have to attach close to the centrum. 4, speculative version of cervical 14 with the epipophyses extended posteriorly as long bony processes. Such processes would allow the bulk of both the dorsal and ventral neck muscles to be located more posteriorly in the neck, but they are not present in any known sauropod or other nonavian dinosaur. Modified from Wiman (1929, plate 3).

(https://svpow.files.wordpress.com/2012/09/fig11-force-lines-on-a-cladogram.jpeg) Figure 11. Archosaur cervical vertebrae in posterior view, Showing muscle attachment points in phylogenetic context. Blue arrows indicate epaxial muscles attaching to neural spines, red arrows indicate epaxial muscles attaching to epipophyses, and green arrows indicate hypaxial muscles attaching to cervical ribs. While hypaxial musculature anchors consistently on the cervical ribs, the principle epaxial muscle migrate from the neural spine in crocodilians to the epipophyses in non-avial theropods and modern birds, with either or both sets of muscles being significant in sauropods. 1, fifth cervical vertebra of Alligator mississippiensis, MCZ 81457, traced from 3D scans by Leon Claessens, courtesy of MCZ. Epipophyses are absent. 2, eighth cervical vertebra of Giraffatitan brancai paralectotype HMN SII, traced from Janensch (1950, figures 43 and 46). 3, eleventh cervical vertebra of Camarasaurus supremus, reconstruction within AMNH 5761/X, “cervical series I”, modified from Osborn and Mook (1921, plate LXVII). 4, fifth cervical vertebra of the abelisaurid theropod Majungasaurus crenatissimus,UA 8678, traced from O’Connor (2007, figures 8 and 20). 5, seventh cervical vertebra of a turkey, Meleagris gallopavo, traced from photographs by MPT.

Figures from the preprint Three of the figures changed between the version of the paper that was posted as a preprint on arXiv and the final published version on PeerJ. The figures shown above are the final published versions. Here are the full-resolution versions of the three arXiv figures that were subsequently changed. Figure 1 originally included Deinocheirus, which was subsequently excised from the paper at the editor’s request. Tanystropheus was added. The original figure’s human skull, giraffe, ostrich, Paraceratherium, Therizinosaurus and Gigantoraptor were all copyright-encumbered, so were replaced by versions that can be distributed under CC BY.

(https://svpow.files.wordpress.com/2012/09/fig1-non-sauropod-neck-composite.jpeg) Original Figure 1. Necks of long-necked non-sauropods, to the same scale. The giraffe and Paraceratherium are the longest necked mammals; the ostrich is the longest necked extant bird; Therizinosaurus, Deinocheirus and Gigantoraptor are the longest necked representatives of the three long-necked theropod clades and Arambourgiania is the longest necked pterosaur. Arambourgiania scaled from Zhejiangopterusmodified from Witton and Naish (2008, figure 1). Other image sources as for Figure 2. Alternating pink and blue bars are one meter in height. Similarly, Figure 2 originally included Deinocheirus, which was subsequently excised and Tanystropheus added. The original Paraceratherium, Therizinosaurus and Gigantoraptor. being copyright-encumbered, were replaced by versions that can be distributed under CC BY.

(https://svpow.files.wordpress.com/2012/09/fig2-skeletons-of-non-sauropods.jpeg) Original Figure 2. Full skeletal reconstructions of selected long-necked non-sauropods, to the same scale. 1, Paraceratherium, modified from Granger and Gregory (1936, figure 47). 2, Therizinosaurus, scaled from Nanshiungosaurus modified from Paul (1997, p. 145). 3, Deinocheirus, scaled from Struthiomimus modified from Osborn (1916, plate XXVI). 4, Gigantoraptor, modified from Xu el al. (2007, figure 1). 5. Elasmosaurus, modified from Cope (1870, plate II, figure 1). Scale bar = 2 m. In the original figure 3, sauropod necks from various sources were used. We replaced these with Scott Hartman’s reconstructions (except for Hatcher’s Diplodocus) partly for consistency and partly to avoid copyright encumbrance.

(https://svpow.files.wordpress.com/2012/09/fig3-sauropod-neck-composite.jpeg) Original Figure 3. Necks of long-necked sauropods, to the same scale. Diplodocus, modified from elements in Hatcher (1901, plate 3), represents a “typical” long-necked sauropod, familiar from many mounted skeletons in museums. Puertasaurus modified from Wedel (2007a, figure 4-1). Sauroposeidon scaled from Brachiosaurus artwork by Dmitry Bogdanov, via commons.wikimedia.org (http://commons.wikimedia.org/) (CC-BY-SA). Mamenchisaurus modified from Young and Zhao (1972, figure 4). Supersaurus scaled from Diplodocus, as above. Alternating pink and blue bars are one meter in width. Inset shows Figure 1 to the same scale. x Posted by Mike Taylor Filed in 21 Comments »

Hot sauropod news, part 2: A new look for Sauroposeidon September 5, 2012

(https://svpow.files.wordpress.com/2012/08/sauroposeidon-dorsal-ypm-5449-demic-and-foreman-2012-fig-6aand-c.jpg) YPM 5449, a posterior dorsal vertebra of Sauroposeidon, from D’Emic and Foreman (2012:fig. 6A and C). Another recent paper (part 1 is here (https://svpow.com/2012/06/28/hot-sauropod-news-part-1-rampant-pneumaticity-in-saltasaurines/)) with big implications for my line of work: D’Emic and Foreman (2012), “The beginning of the sauropod dinosaur hiatus in North America: insights from the Lower Cretaceous Cloverly Formation of Wyoming.” In it, the authors sink Paluxysaurus into Sauroposeidon and refer a bunch of Cloverly material to Sauroposeidon as well. So in one fell swoop Sauroposeidon goes from being one of the most poorly represented Early Cretaceous North American sauropods, based on just four vertebrae from a single individual, to one of the best-known, most complete, and most widespread, based on at least seven individuals from Texas, Oklahoma, and Wyoming. The web of connections among the different sets of material is complex, and involves the Sauroposeidon holotype OMNH 53062 from the Antlers Formation of southeastern Oklahoma, the type and referred material of Paluxysaurus from the Twin Mountains Formation of northern Texas described by Rose (2007), sauropod material from the Cloverly Formation of north-central Wyoming described and illustrated by Ostrom (1970), and UM 20800, a scap and coracoid newly excavated from one of Ostrom’s old quarries. D’Emic and Foreman argue that (1) the Cloverly material is referable to Sauroposeidon based on the shared derived characters of a juvenile cervical, YPM 5294, and the Sauroposeidon holotype, and (2) Paluxysaurus is not distinguishable from the Cloverly material and in fact shares several autapomorphies with the Cloverly sauropod. Which means that (3) Paluxysaurus is Sauroposeidon.

But that’s not all! All the new material suggests different phylogenetic affinities for Sauroposeidon. Instead of a brachiosaurid, it is now posited to be a basal somphospondyl. That’s not super-surprising; as we noted back in 2000 (Wedel et al. 2000), if Sauroposeidon was a brachiosaurid it had evolved some features in parallel with titanosaurs, most notably the fully camellate internal structure of the cervical vertebrae. And it also makes sense because other basal somphospondyls include Erketu and Qiaowanlong, the cervicals of which are similar to Sauroposeidon in some features. D’Emic and Foreman (2012) cite a forthcoming paper by Mike D’Emic in the Journal of Systematic Paleontology that contains the cladistic analysis backing all this up, but the case based on comparative anatomy is already pretty strong. If anyone is unconvinced by all of these referrals, please bear in mind that we haven’t heard the whole story yet, quite probably for reasons that are outside of the authors’ control. I am inclined to be patient because I have been in that situation myself: Wedel (2003a) was intended to stand on the foundation of evidence laid down by Wedel (2003b), but because of the vagaries of publication schedules at two different journals, the interpretive paper beat the descriptive one into press by a couple of months.

(https://svpow.files.wordpress.com/2012/08/paluxysaurus-c5-rose-2007-figure-10.jpg) Mid-cervical originally described as Paluxysaurus, now referred to Sauroposeidon, from Rose (2007:fig. 10). Anyway, if anyone wants my opinion as “Mr. Sauroposeidon“, I think the work of D’Emic and Foreman (2012) is solid and the hypothesis that Paluxysaurus is Sauroposeidon is reasonable. So, if I think it’s reasonable now, why didn’t I synonymize the two myself? Partly because I thought there was a pretty good chance the two were not the same, based mostly on FWMSH 93B-10-8 (which I referred to as FWMSH “A” in Wedel 2003b, since I had only seen in on display without a specimen number), which I thought looked a lot more like a titanosaur cervical than a brachiosaur cervical. But of course I thought Sauroposeidon was a brachiosaur until a couple of months ago, and if it ain’t, and if brachiosaurs and basal somphospondyls have similar cervicals, that objection is considerably diminished. And partly because I’ve had other things to be getting on with, and stopping everything else to spend what would realistically be a few months looking into a possible synonymy (that I didn’t strongly suspect) wasn’t feasible in terms of time or geography. So I’m glad that D’Emic and Foreman have done that work, and I’m excited about the new things they’ve uncovered.

(https://svpow.files.wordpress.com/2012/08/bob-nicholls-sauroposeidon-v4a.jpg) And I’m honored to bring you a new life restoration of Sauroposeidon by uber-talented Bob Nicholls, which we think is the first to show Sauroposeidon in its new guise as a basal somphospondyl. Click through for the mega-awesome version.

(https://svpow.files.wordpress.com/2012/08/bob-nicholls-sauroposeidon-v4b.jpg) Same critter, different views. If anyone wants to GDI (https://svpow.com/2011/01/20/tutorial-11-graphic-double-integration-or-weighing-dinosaurs-on-the-cheap/)this baby, you now have everything you need. Many thanks to Bob for permission to post these and the following making-of images. Please visit him at Paleocreations.com (http://www.paleocreations.com/) to see a ton of awesome stuff, and give him some love–or at least a few thousand “likes”–on Facebook (http://www.facebook.com/Paleocreations). This is Bob’s first foray into 3D modeling, but you’d never know from the quality of his virtual sculpt. And let me tell you, that dude works fast. He sent this initial version, showing Sauroposeidon as an attenuated brachiosaur (sorta like this (https://svpow.com/2009/08/07/how-tallweird-was-sauroposeidon/)) on August 23, to solicit comments from Mike and me.

(https://svpow.files.wordpress.com/2012/09/sauroposeidon01.jpg)

(https://svpow.files.wordpress.com/2012/09/sauroposeidon02.jpg) I wrote back and let Bob know about the new work of D’Emic and Foreman, and suggested that he could probably be the first to restore Sauroposeidon as a somphospondyl. Mike and I also voiced our opposition to the starvation-thinned neck (https://svpow.com/2011/11/18/sideshow-collectibles-apatosaurus-maquette-part-3-the-neck/), and Mike suggested that the forelimb was too lightly muscled and that the ‘fingers’ were probably too prominent. The very next day, this was in our inboxes:

(https://svpow.files.wordpress.com/2012/09/sauroposeidon2-a.jpg)

(https://svpow.files.wordpress.com/2012/09/sauroposeidon2-b.jpg) I wrote back: Whatever Sauroposeidon was, its neck was fairly tall and skinny in cross-section. It looks like the neck on your model sort of tapers smoothly from the front of the body to the head. I think it would be much narrower, side-to-side, along most of its length, and would have a more pronounced shoulder-step where it met the body. The bottom view is very useful. It shows the forefeet as being about the same size as the hindfeet. AFAIK all or nearly all known sauropod tracks have much bigger hindfeet than forefeet. Certainly that is the case with Brontopodus birdi, the big Early Cretaceous sauropod tracks from Texas that were probably made by Sauroposeidon. The forefeet should be about 75-80% the width of the hindfeet, and only about half a long front-to-back. Even if you don’t quite get to those numbers, shrinking the forefeet a bit and subtly up-sizing the hindfeet would make the model more accurate. Mike’s commentary was much shorter–and funnier: I like how freaky it looks. It looks WRONG, but in a good way. Bob toiled over the weekend and came back with this subtly different, subtly better version:

(https://svpow.files.wordpress.com/2012/09/sauroposeidon3a-cnicholls2012.jpg)

(https://svpow.files.wordpress.com/2012/09/sauroposeidon3b-cnicholls2012.jpg) I had one more change to recommend: I’m sorry I didn’t suggest this sooner, but it only just now occurred to me. With the referral of Paluxysaurus and the Cloverly material to Sauroposeidon, we now have dorsal vertebrae, and they are loooong, much more similar in proportion to the dorsals of Brachiosaurus altithorax than those of Giraffatitan brancai. So, as much as I like the compact little body on your Sauroposeidon, I think it was probably fairly long in the torso. You probably already have Mike’s Brachiosaurus paper [Taylor 2009] with the skeletal recon showing the long torso–in the absence of an updated skeletal recon for Sauroposeidon, I’d use Mike’s Figure 7 as a guide for reconstructing the general body proportions. Bob lengthened the torso to produce the final version, which is the first one I showed above. He sent that over on August 29–the delay in getting this post up rests entirely with me. So. It is still very weird to think of “my” dinosaur as a somphospondyl rather than a brachiosaur. I had 15 years (http://sauroposeidon.files.wordpress.com/2010/04/wedel-1997-bs-thesis.pdf) to get used to the latter idea. But suddenly having a lot more material–essentially the whole skeleton, minus some stinkin’ skull bits–is pretty darned exciting, and the badass new life restoration doesn’t hurt, either. Now, would it be too much to wish for some more Brontomerus?

References D’Emic, M.D., and B.Z. Foreman. 2012. The beginning of the sauropod dinosaur hiatus in North America: insights from the Lower Cretaceous Cloverly Formation of Wyoming. Journal of Vertebrate Paleontology 32(4): 883-902. Ostrom, J.H. 1970. Stratigraphy and paleontology of the Cloverly Formation (Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana. Peabody Museum Bulletin 35: 1234. Rose, Peter J. 2007. A new titanosauriform sauropod (Dinosauria: Saurischia) from the Early Cretaceous of central Texas and its phylogenetic relationships. Palaeontologia Electronica 10(2): 8A (65 pp.) (http://palaeo-electronica.org/2007_2/00063/) Taylor, Michael P. 2009. A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrae Paleontology 29(3): 787-806. (http://www.miketaylor.org.uk/dino/pubs/taylor2009/Taylor2009-brachiosaurus-and-giraffatitan.pdf) Wedel, M.J. 2003a. Vertebral pneumaticity, air sacs, and the physiology of sauropod dinosaurs. Paleobiology 29: 243-255. (http://sauroposeidon.files.wordpress.com/2010/04/wedel2003-sauropod-pneumaticity.pdf) Wedel, M.J. 2003b. The evolution of vertebral pneumaticity in sauropod dinosaurs. Journal of Vertebrate Paleontology 23: 344-357. (http://sauroposeidon.files.wordpress.com/2010/04/wedel-2003-evolution-of-pneumaticity.pdf) Wedel, M.J., R.L. Cifelli and R.K. Sanders. 2000. Osteology, paleobiology, and relationships of the sauropod dinosaur Sauroposeidon. Acta Palaeontologica Polonica 45(4): 343-388. (http://sauroposeidon.files.wordpress.com/2010/04/wedel-et-al-2000-sauroposeidon-in-acta.pdf) Posted by Matt Wedel Filed in cervical, dorsal, life restorations, Sauroposeidon 22 Comments »

Hot sauropod news, part 1: rampant pneumaticity in saltasaurines June 28, 2012

(https://svpow.files.wordpress.com/2012/06/caudal-pneumaticity-in-saltasaurines-cerda-et-al-2012-fig-1.jpg) Caudal pneumaticity in saltasaurines. Cerda et al. (2012: fig. 1). Earlier this month I was amazed to see the new paper by Cerda et al. (2012), “Extreme postcranial pneumaticity in sauropod dinosaurs from South America.” The title is dramatic, but the paper delivers the promised extremeness in spades. Almost every figure in the paper is a gobsmacker, starting with Figure 1, which shows pneumatic foramina and cavities in the middle and even distal caudals of Rocasaurus, Neuquensaurus, and Saltasaurus. This is most welcome. Since the 1990s there have been reports of saltasaurs with “spongy bone” in their tail vertebrae, but it hasn’t been clear until now whether that “spongy bone” meant pneumatic air cells or just normal marrow-filled trabecular bone. The answer is air cells, loads of ’em, way farther down the tail than I expected.

(https://svpow.files.wordpress.com/2012/06/diplodocine-caudal-pneumaticity.jpg) Caudal pneumaticity in diplodocines. Top, transverse cross-section through an anterior caudal of Tornieria, from Janensch (1947: fig. 9). Bottom, caudals of Diplodocus, from Osborn (1899: fig. 13). Here’s why this is awesome. Lateral fossae occur in the proximal caudals of lots of neosauropods, maybe most, but only a few taxa go in for really invasive caudal pneumaticity with big internal chambers. In fact, the only other sauropod clade with such extensive pneumaticity so far down the tail are the diplodocines, including Diplodocus, Barosaurus, and Tornieria. But they do things differently, with BIG, “pleurocoel”-type foramina on the lateral surfaces of the centra, leading to BIG–but simple–camerae inside, and vertebral cross-sections that look like Ibeams. In contrast, the saltasaurines have numerous small foramina on the centrum and neural arch that lead to complexes of small pneumatic camellae, giving their vertebrae honeycomb cross-sections. So caudal pneumaticity in diplodocines and saltsaurines is convergent in its presence and extent but clade-specific in its development. Pneumaticity doesn’t get much cooler than that.

(https://svpow.files.wordpress.com/2012/06/iliac-pneumaticity-in-saltasaurines-cerda-et-al-2012-fig-3.jpg) Pneumatic ilia in saltasaurines. Cerda et al. (2012: fig. 3). But it does get a little cooler. Because the stuff in the rest of the paper is even more mind-blowing. Cerda et al. (2012) go on to describe and illustrate–compellingly, with photos–pneumatic cavities in the ilia, scapulae, and coracoids of saltasaurines. And, crucially, these cavities are connected to the outside by pneumatic foramina. This is important. Chambers have been reported in the ilia of several sauropods, mostly somphospondyls but also in the diplodocoid Amazonsaurus. But it hasn’t been clear until now whether those chambers connected to the outside. No patent foramen, no pneumaticity. It seemed unlikely that these sauropods had big marrow-filled vacuities in their ilia–as far as I know, all of the non-pneumatic ilia out there in Tetrapoda are filled with trabecular bone, and big open marrow spaces only occur in the long bones of the limbs. And, as I noted in my 2009 paper (https://svpow.com/papers-by-sv-powsketeers/wedel2009-on-air-sacs/), the phylogenetic distribution of iliac chambers is consistent with pneumaticity, in that the chambers are only found in those sauropods that already have sacral pneumaticity (showing that pneumatic diverticula were already loose in their rear ends). But it’s nice to have confirmation. So, the pneumatic ilia in Rocasaurus, Neuquensaurus, and Saltasaurus are cool because they suggest that all the other big chambers in sauropod ilia were pneumatic as well. And for those of you keeping score at home, that’s another parallel acquisition in Diplodocoidea and Somphospondyli (given the apparent absence of iliac chambers in Camarasaurus and the brachiosaurids, although maybe we should bust open a few brachiosaur ilia just to be sure*). * I kid, I kid.** ** Seriously, though, if you “drop” one and find some chambers, call me!

(https://svpow.files.wordpress.com/2012/06/pectoral-pneumaticity-in-saltasaurines-cerda-et-al-2012-fig-2.jpg) Pectoral pneumaticity in saltasaurines. Cerda et al. (2012: fig. 2). But that’s not all. The possibility of pneumatic ilia has been floating around for a while now, and most of us who were aware of the iliac chambers in sauropods probably assumed that eventually someone would find the specimens that would show that they were pneumatic. At least, that was my assumption, and as far as I know no-one ever floated an alternative hypothesis to explain the chambers. But I certainly did not expect pneumaticity in the shoulder girdle. And yet there they are: chambers with associated foramina in the scap and coracoid of Saltasaurus and in the coracoid of Neuquensaurus. Wacky. And extremely important, because this is the first evidence that sauropods had clavicular air sacs like those of theropods and pterosaurs. So either all three clades evolved a shedload of air sacs independently, or the basic layout of the avian respiratory system was already present in the ancestral ornithodiran. I know where I’d put my money (https://svpow.com/2009/05/08/x-men-origins-pneumaticity/). There’s loads more interesting stuff to talk about, like the fact that the ultra-pneumatic saltasaurines are among the smallest sauropods, or the way that fossae and camerae are evolutionary antecedent to camellae in the vertebrae of sauropods, so maybe we should start looking for fossae and camerae in the girdle bones of other sauropods, or further macroevolutionary parallels in the evolution of pneumaticity in pterosaurs, sauropods, and theropods. Each one of those things could be a blog post or maybe a whole dissertation. But my mind is already thoroughly blown. I’m going to go lie down for a while. Congratulations to Cerda et al. on what is probably the most important paper ever written on sauropod pneumaticity. References Cerda, I.A., Salgado, L., and Powell, J.E. 2012. Extreme postcranial pneumaticity in sauropod dinosaurs from South America. Palaeontologische Zeitschrift. DOI 10.1007/s12542-0120140-6 Janensch, W. 1947. Pneumatizitat bei Wirbeln von Sauropoden und anderen Saurischien. Palaeontographica, Supplement 7, 3:1–25. Osborn, H. F. 1899. A skeleton of Diplodocus. Memoirs of the American Museum of Natural History 1:191–214. Posted by Matt Wedel Filed in caudal, coracoid, cross sections, diplodocids, Diplodocus, ilium, Neuquensaurus, pneumaticity, Rocasaurus, Saltasaurus, scapula, stinkin' appendicular elements, titanosaur, Tornieria 9 Comments » Create a free website or blog at WordPress.com.