Today saw the publication of the most startlingly dull paper I’ve ever been involved in (Upchurch et al. 2009) — and remember, I write this as co-author of a paper on the phylogenetic taxonomy of Diplodocoidea.  Not only that, but one time when I was practising a conference talk with my wife Fiona as audience, she fell asleep actually while I was speaking.  Actually asleep.  And yet the new paper beats them all hands-down for boredom.  If you don’t believe me, feast your eyes, gloat your soul, on the accursed ugliness of the very title of the new paper: “Case 3472: Cetiosaurus Owen, 1841 (Dinosauria, Sauropoda): proposed conservation of usage by designation of Cetiosaurus oxoniensis Phillips, 1871 as the type species.”  What is it all about?

Well, take a look at the type material of Cetiosaurus:

Upchurch and Martin (2003: fig. 2) -- type material of Cetiosaurus medius

Type material of Cetiosaurus medius, from Upchurch and Martin (2003: fig. 2). Scale bars 50 mm.

Yes indeed — the most historically important of all sauropods is based on a set of non-diagnostic uninformative eroded partial mid-to-distal caudal centra.  That is because this is the type material of the species which, for complex technical reasons, is the type species of the genus Cetiosaurus.  We tend to ignore this fact because the material is clearly rubbish: the taxon C. medius is not valid.  Sadly, however, the name C. medius is valid — nomenclaturally valid, even though it’s not taxonomically valid.  But the International Code of Zoological Nomenclature (ICZN), which governs all zoological nomenclature, is purely a code of nomenclature, and does not take taxonomic considerations such as diagnosability into account.  (It can’t, after all: how could the code contain rigorous rules that let you determine whether material is diagnostic, or whether a description is adequate?)

Anyway, the material of C. brevis, C. brachyurus, C. medius and C. longus, all published together (Owen 1842) is all pretty useless; but Phillips (1871) described in detail the much better material of a new species C. oxoniensis, and this is what everyone has meant by the name Cetiosaurus ever since.  Upchurch and Martin (2003:215) even explicitly stated that they were provisionally using C. oxoniensis as the de facto type speces, pending a petition to the ICZN to overrule strict priority.  And no wonder: the C. oxoniensis material really is way better.  For example, check out this dorsal vertebra (which is by no means the best one — just one that I have a convenient photo of):

Cetiosaurus oxoniensis referred partial dorsal vertebra OUMNH J13648, right lateral view

Cetiosaurus oxoniensis partial dorsal vertebra OUMNH J13648 (part of the lectotype series), right lateral view

Today’s new paper is that long-promised petition: in it, we recount the nomenclatural history of the name Cetiosaurus and its species, explain with a big list of references that C. oxoniensis has been overwhemingly used historically and is overwhelmingly used today, and ask the Commission to legitimise this universal behaviour.

Will they do it?  We actually don’t know, although I can’t think of any reason why they shouldn’t.  The process now is that interested workers can send their comments, either in favour of or against our proposal, to the Executive Secretary of the ICZN (address at the end of the PDF), and these comments are weighed before a decision is returned.  From my informal sampling of previous petitions, the process seems to take between one and two years.  So we’re probably stuck in type-species limbo until 2011.  Oh well — at least the main step has been taken.

So.  I’m not exactly as excited about this paper as I was of Xenoposeidon — don’t worry, we won’t be launching a nine-post Cetiosaurus Type Species Redesignation Week — nor as pleased with it as I am with a certain in-press paper that all three of us SV-POW!sketeers are very much looking forward to because REDACTED.  But it’s a dirty job that someone had to do.

References

  • Owen, Richard.  1841.  A description of a portion of the skeleton of the Cetiosaurus, a gigantic extinct saurian reptile occurring in the oolitic formations of different portions of England.  Proceedings of the Geological Society of London 3: 457-462.
  • Owen, Richard.  1842b.  Report on British fossil reptiles, Part II. Reports of the British Association for the Advancement of Science 11: 60-204.
  • Phillips, John.  1871.  Geology of Oxford and the valley of the Thames.  Clarendon Press, Oxford.
  • Upchurch, Paul, and John Martin.  2003.  The anatomy and taxonomy of Cetiosaurus (Saurischia, Sauropoda) from the Middle Jurassic of England.  Journal of Vertebrate Paleontology 23: 208-231.
  • Upchurch, Paul, John Martin, and Michael P. Taylor.  2009.  Case 3472: Cetiosaurus Owen, 1841 (Dinosauria, Sauropoda): proposed conservation of usage by designation of Cetiosaurus oxoniensis Phillips, 1871 as the type species. Bulletin of Zoological Nomenclature 66 (1): 51-55.

Update (3 April 2009)

Here’s that photograph of a leopard seal pulling the head right off a penguin you ordered:

Leopard seal PULLING THE HEAD RIGHT OFF a penguin

Leopard seal PULLING THE HEAD RIGHT OFF a penguin

Acknowledgement: I got this photo from http://img238.imageshack.us/img238/873/1627.jpg.  Thanks to “Paul A.” (see comment below) I now know that it is the work of Paul Nicklen who has a stellar collection of photographs on his own site.  This picture is entitled The Death Shake, and is the 10th of the 29 pictures in his leopard seal gallery.

Relevant Update (31 August 2010)

I should have noted this long ago, but back in July 2009 (more than a year ago!) Paul Barrett and Pete Galton both published comments in the BZN that were supportive of our petition.

As Matt frequently reminds me, it’s now nearly five years since I started to work on “The Archbishop”, more formally known as BMNH R5973, the Natural History Museum’s long-neglected Tendaguru brachiosaur.  This is, or at least once was, one of the most complete brachiosaurid specimens ever discovered — although quite a bit of the material has gone missing or remains unprepared.  It’s true that I owe the world a proper description, especially since I spoke about the specimen as long ago as the 2005 SVPCA (Symposium of Vertebrate Palaeontology and Comparative Anatomy) and have been sitting on it ever since.  So: you have my apologies, along with a promise to get into gear RSN.

But what I want to know is this: since this specimen is radioactive, and I’ve been working with it for five years now, surely according to all the rules of literature, I should by now have developed brachiosaurid superpowers?  At the very least, the ability to have a neck way long compared with my body:

Left to right: Mike with brachiosaurid superpowers, Matt with no superpowers, Darren being mundane.

Left to right: Mike with brachiosaurid superpowers, Matt with no superpowers, Darren being mundane.

Better still would be the ability to crush my enemies to dust beneath my Mighty Forefeet of Justice.  And yet, so far, nothing.  It doesn’t seem fair somehow.

Since we’re talking about the Archbishop, let’s take a look at Cervical U, the best preserved of the five cervicals that are available for study:

Tendaguru brachiosaurid BMNH R5937, "The Archbishop", cervical U in right lateral view.  Copyright the Natural History Museum, since it's their material.

Tendaguru brachiosaurid BMNH R5937, "The Archbishop", cervical U in right lateral view. Copyright the Natural History Museum, since it's their material.

When it was found in 1930, in an expedition to Tendaguru, Tanzania, led by F. W. H. Migeod, the Archbishop consisted of an articulated vertebral column all the way from cervical 5 through to caudal 8 or so — by far the best vertebral sequence of any brachiosaur — along with cervical and dorsal ribs, a scapula, both humeri, pelvic elements and a partial femur.  At least, if you believe Migeod; but the material that made it back to London, survived the Second World War and has been prepared is a fraction of that: five cervicals in various states of repair, some cervical ribs, two excellent dorsals (featured previously, though not in a big way), two further dorsal centra and a dorsal neural spine, an indeterminate long-bone fragment and a smushed proximal pubis.  Migeod measurements make it seem unlikely that all the material really belongs to a single animal — for example, the humeri seem much too short — but the articulation of the vertebrae makes their associated pretty rock solid.  And that is plenty enough to make this an awesome specimen.

Here is Migeod’s quarry map:

BMNH R5937 quarry map, from Migeod (1930:fig. 1)

BMNH R5937 quarry map, from Migeod (1930:fig. 1)

I don’t want to say too much more about the Archbishop for fear of stealing my own thunder, but it’s no secret that I don’t think it’s Brachiosaurus brancai.  For those who want to know more, the slides from my 2005 SVPCA talk are available.  Enjoy!

References

Isn’t this a beauty?

Alleged "Diplodocus dorsal bone", posterior view

Alleged "Diplodocus dorsal bone", posterior view

What is it, you ask?   We will never know.  A friend of mine pointed me to a forthcoming fossil auction by I. M. Chait, and as I scrolled through all the crappy ornithopod skeletons and suchlike, my eye was caught by this bone, described as a “Diplodocus dorsal bone”, from the Bone Cabin quarry in Wyoming.  “The dorsal bone most likely came from close to the back of the head[?!]“.

Whatever it is, it ain’t Diplodocus: the metapophyses are too low, the intraspinal trough is not deep enough, the diapophyses are too high up, they’re laterally rather than ventrolaterally inclined, the hyposphene is way too big and too triangular, the centrum is subquadrangular rather than ovoid, the centropostzygapophyseal laminae are absent … I could go on.  If you don’t believe me, here is the complete set of Dipodocus carnegii dorsals, from Hatcher (1901: plate VIII): posterior to anterior running from left to right; anterior, posterior and right lateral views from top to bottom.

hatcher1901-plate-xiii-diplodocus-carnegii-dorsals-480px

Hatcher 1901, plate XIII: dorsal vertebrae of Diplodocus carnegii CM 84

Not even close.

So what actually is the for-sale vertebra?  Of course there is only so much you can say from a single photograph, but it looks very much as though this is something new, as yet undescribed.  Unknown to science, in fact.  I say that largely because of the those bizarre dorsolaterally oriented struts which extend from the sides of the neural arch to meet and merge with the diapophyses.  I don’t recall ever having seen anything like that.  In general proportions, too, this vertebra is distinctly odd.

Unknown to science it is, and unknown to science it will remain — if, as seems likely, some rich idiot buys this as a trophy to sit on his cocktail bar.  Hence the righeous fury alluded to in the title: so far as the wider world is concerned, so far as our understanding of Morrison Formation ecological diversity is concerned, so far as our understanding of sauropod disparity is concerned, this vertebra might just as well have stayed in the ground.

Unless.

If anyone reading this blog is a rich benefactor, then just maybe this vert could be rescued: bought by someone who appreciates its scientific significance, and donated to an accredited museum, where it can be properly reposited and scientifically studied.  So if any of you out there have $5000 to spare and fancy a decent chance at getting a sauropod named after you, you know what to do.

I’ve hestitated about publishing this post, because of the danger that it will become sufficiently widely known to push the price up.  The last thing I want is to make more money for the fossil dealers responsible for taking this thing out of the hands of scientists.  But I figured it’s worth the risk.  Let’s hope I’m right.

[To be absolutely clear: I. M. Chait did not solicit me to write this, neither do they even know about it, and I am pretty sure they would not be happy about it if they did.]

Reference

  • Hatcher, Jonathan Bell.  1901.  Diplodocus (Marsh): its osteology, taxonomy and probable habits, with a restoration of the skeleton.  Memoirs of the Carnegie Museum, 1: 1-63 and plates I-XIII.

Update (23 March 2009)

We have heard from an SV-POW! reader who is looking into buying this specimen and donating it to a museum.  Which would be awesome.  (I won’t mention his or her name at this stage until he or she authorises me to do so.)  That being so, please no-one else try the same thing — we last thing we want is for two readers to get into a bidding war!

tianyulong

That clanking sound you just heard was pretty much the entire field of paleontology evolutionary biology wired humanity dropping a solid gold brick: Tianyulong, a basal ornithischian from (where else?) China, has been found with dino-fuzz (Zheng et al. 2009). Not exactly protofeathers, but pretty darn similar. And if they’re in theropods and ornithischians, they were probably primitive for Dinosauria (at least; comparisons of these integumentary structures to pterosaur ‘hair’ are probably coming). It’s certainly possible that the common ancestor of Ornithodira (the pterosaurs+dinosaurs clade, which encompasses most non-croc-line archosaurs) was fuzzy.

(So much for the “fact” that we “know” that small dinosaurs couldn’t have been endotherms because of their naked skin–see, e.g., pretty much everything ever written by Feduccia, Ruben, and the rest of the BANDits [Birds Are Not Dinosaurs cultists]).

The holotype of <i>Tianyulong</i> (Zheng et al. 2009:fig. 1a)

The holotype of Tianyulong (Zheng et al. 2009:fig. 1a)

It’s true that we have skin impressions from many dinosaurs that show scaly skin, so if dino-fuzz was primitive for dinosaurs it must have been lost, or had a restricted distribution on the body (like a midline crest), or been ontogenetically transient (possibly present only in babies) in many taxa. If there were any shaggy sauropod skin impressions out there, we’d really, RE-hee-huh-HEEELLY like to know. So far, zip. Even the skin impressions from the Argentinian sauropod embryos show bare, scaly skin (Chiappe et al. 1998).

paul1994-fig15-3-sauropod-hatchling-480

Still, those skin patches don’t cover the entire embryo. We can’t rule out some fuzz even in the Argentinian embryos, and except for a scrap of bone shard of excellence here and there (Britt and Naylor 1994), sauropod embryos and their skin are otherwise ridiculously unknown to our planet. So we can dream, for a while longer anyway. Back in 1994, Greg Paul drew a hatchling sauropod with dino-fuzz (Paul 1994:fig. 15.3, above), and we’re bringing it back in honor of Tianyulong.

mike-with-brontosaurus-480

Here’s your obligatory sauropod vert shot for this post. Tremble as the ancient, bloated hulk looms out of the mists of deathless time, like an ageworn stone idol or some eldritch Lovecraftian horror!

Oh, and behind Mike you can just make out the AMNH Brontosaurus (yeah, we know, we’d like to bring that back, too).

UPDATE: MARCH 19

James O’Donoghue wrote a piece for New Scientist on sauropod gigantism, which you can read for free here. He kindly cited my work on air sacs, and even more kindly threw in a link to an SV-POW! post, which I’ll let you find for yourself. Now that I’m sending you there, the hyperlink circle is complete.

Two great things came in the mail yesterday, but those will be subjects of future posts. Stay tuned, true believers!

References

  • Britt, B.B., and Naylor, B.G. 1994. An embryonic Camarasaurus (Dinosauria, Sauropoda) from the Upper Jurassic Morrison Formation (Dry Mesa Quarry, Colorado); pp. 256-264 in Carpenter, K., Hirsch K.F., and Horner, J.R. (eds), Dinosaur Eggs and Babies. Cambridge University Press, Cambridge.
  • Chiappe, L. M., Coria, R. A., Dingus, L., Jackson, F., Chinsamy, A., and Fox, M. 1998. Sauropod dinosaur embryos from the Late Cretaceous of Patagonia. Nature 396: 258–261.
  • Paul, G.S. 1994. Dinosaur reproduction in the fast lane: implications for size, success, and extinction; pp. 244-255 in Carpenter, K., Hirsch K.F., and Horner, J.R. (eds), Dinosaur Eggs and Babies. Cambridge University Press, Cambridge.
  • Zheng, X.-T., You, H.-L., Xu, X., and Dong, Z.-M. 2009. An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures. Nature 458:333-336.

I made this, just for the heck of it.

big-brachiosaurids-and-pathetic-mammals-480

The critters are, from left to right:

  • OMNH 53062, the holotype of Sauroposeidon proteles, with a reconstructed skeleton grayed in;
  • HM XV2, a fibula of Brachiosaurus brancai, which represents the largest known individual of Brachiosaurus;
  • HM SII, the nearly complete mounted composite skeleton of Brachiosaurus brancai in Berlin;
  • a 20-foot-tall, world record giraffe;
  • a 6’2″ human being, such as myself.

The vertebrae of Sauroposeidon are about a third longer than their counterparts in HM SII, but only about 15% larger in diameter. I have therefore always scaled up the body of Sauroposeidon by only 15% relative to HM SII. It may have been bigger or smaller, I’m just trying to follow what few numbers I have to go on as slavishly, and conservatively, as possible. Sauroposeidon is shown here with a more vertical neck than Brachiosaurus because that’s how I had the necks posed in the  two separate skeleton reconstructions before I decided to combine them, and I’m lazy, and that’s not the point of the post anyway.

The point of the post, or the first point anyway, is that almost everyone, everywhere, at all times underestimates the size of Brachiosaurus. This is because of the immense influence of the HM SII mounted skeleton. Practically every estimate of length or neck length or browsing height or mass or anything else for Brachiosaurus is based on that one skeleton. But we know that there were bigger individuals of Brachiosaurus roaming around, like HM XV2, which was 12-13% larger. Not only that, but we can be pretty certain that HM SII was not fully mature because the scapula and coracoid are unfused, and we know these elements are fused into a single scapulocoracoid in mature brachiosaurids. So between SII being not all grown up and XV2 being considerably bigger, we ought to think of XV2 and not SII when we think about big Brachiosaurus was.

Now, 12-13% might not seem like much, but it’s considerable. It’s the difference between me (6’2″) and someone seven feet tall. HM SII has a neck 8.5 meters long; that of XV2 would have been 9.5 meters long, which is longer than the neck of the holotype of Mamenchisaurus hochuanensis (9 m), but shorter than the estimated neck length of Mamenchisaurus sinocanadorum (~12m).

Crucially, XV2 would have massed 1.4 times as much as SII (1.125^3, because mass depends on volume, which scales with the cube of length). That holds true no matter how much you think SII weighed. If SII had a mass of 40 tons, then XV2 was 56 tons; if SII was 30 tons, XV2 was still 42 tons.

Maybe the most interesting thing about this is that, so far as we can tell, XV2 was almost exactly the same size as the holotype individual of Sauroposeidon. So anything I or anyone else has written about Sauroposeidon being bigger, absolutely, than Brachiosaurus, is bobbins. Sauroposeidon still had a considerably longer neck, 11.5 meters to XV2’s 9.5, but the cervical skeleton weighed about the same thanks to the higher air space proportion in Sauroposeidon. In fact, if the higher ASP of Sauroposeidon applied to the rest of the vertebral column, then the holotype individual of Sauroposeidon might have weighed less than XV2!

The evolutionary upshot is that, as far as we can tell, big brachiosaurids stayed about the same size from the Kimmeridgian-Tithonian (Late Jurassic) to the Aptian-Albian (Early Cretaceous). Maybe they hit some kind of limit, but I doubt it, because Argentinosaurus was probably a lot heavier and Bruhathkayosaurus and Amphicoelias would have knocked any known brachiosaurid right out of the park. I think it is more likely that the debits imposed by large body size finally caught up with the selective advantages of same, within that lineage (but not at the same point within other lineages). Whatever the reason, the biggest known brachiosaurid didn’t get any bigger than Brachiosaurus. Which puts the evolution of the longer, more pneumatic neck in Sauroposeidon into a new light. It might have been a cheat, an evolutionary hack to overcome a limit on whole-body growth, even if that limit was a ‘soft’ one imposed by balanced selection pressures in both directions. That’s sort of assuming that Sauroposeidon was just Brachiosaurus with a redesigned front end, but the weirdness we see in the vertebrae might have extended to the rest of the animal. We won’t know until someone digs up some more specimens. Sigh.

The second point of the post is that, as indicated by the title, Brachiosaurus might have been smaller than we commonly think. Since the 1980s there have been a couple of ~30 ton estimates out there for HM SII, one by Anderson et al. (1985) based on limb bone allometry and one by Paul [1988] based on volumetrics (I have to put 1988 publication dates in brackets rather than parentheses or mrrfin’ frrfin’ WordPress automatically changes the 8 and the ) to a smiley, dammit). I think that by and large people have gotten pretty comfortable with the idea that SII was a 30 ton  critter.

But it might–might–have been quite a bit lighter. Paul (1997) assigned the neck a density of 0.6 g/cm^3 and the torso a density of 0.9 g/cm^3. Those are probably too dense. Some birds have necks as un-dense (sparse?) as 0.3 g/cm^3, and that does not strike me as unreasonable for sauropod necks given the amount of pneumaticity indicated by the skeleton. The lungs and air sacs of birds can account for up to 20% of the volume of the body. Not of the torso, of the whole body. And based on my calculations for derived theropods and sauropods, up to 10% of the whole-body volume was occupied by air in the pneumatic bones. That’s 10% in addition to the 20% for the lungs and air sacs, or 30% of the whole body  volume. That would give a whole-body density of about 0.7 g/cm^3, which is in fact what has been found for some birds.

I got 0.8 g/cm^3 for the whole-body density of Diplodocus in my 2005 paper, and other authors have since used that number for other sauropodomorphs. That’s gratifying, but it’s probably wrong. I erred conservatively at every possible point in that calculation and just flat left out some known air spaces whose volume I could not reliably estimate (e.g., vertebral diverticula outside the vertebrae). I also used 10% rather than 20% for the part of the whole-body volume occupied by the lungs and air sacs, because values as low as 10% have been reported for some birds and I was being conservative. But I don’t think that bird-like densities around 0.7 g/cm^3 are unrealistic for sauropods; in fact, I’d be surprised if the really pneumatic ones–like big brachiosaurids–weren’t about that sparse.

And speaking of big brachiosaurids, Henderson (2004) used computerized volumetrics and a density of 0.8 and got a mass of 25.8 tons for HM SII. If the density was really 0.7 that would shave off an additional 10% and bring the mass down to 22.7 tons. That’s getting crazy light; it’s about half of what Bakker and Alexander were proposing for Brachiosaurus in the mid-80s. And it’s still a quarter lighter than what Anderson (1985) and Paul [1988] got.

So, for the sake of argument, let’s say that HM SII did mass only 22.7 tons. That would give XV2 a mass of 32 tons, and Sauroposeidon a mass of only 34.5 tons without taking any additional pneumaticity into account.

That seems totally nuts. But every step is defensible*, and it might even be true.

* That means if you want to tear me a new one in the comments because teh Brachiosaurus wuz 50 tons!!!1!!111!, please be sure to specify which links in the chain of inference you disagree with, and why.

References

  • Anderson, J. F., A. Hall-Martin, and D. A. Russell. 1985. Long-bone circumference and weight in mammals, birds and dinosaurs. Journal of Zoology 207:53-61.

  • Henderson, D. M. 2004. Tipsy punters: sauropod dinosaur pneumaticity, buoyancy and aquatic habits. Proceedings: Biological Sciences 271 (Supplement):S180-S183.

  • Paul, G. S. 1988. The brachiosaur giants of the Morrison and Tendaguru with a description of a new subgenus, Giraffatitan, and a comparison of the world’s largest dinosaurs. Hunteria 2(3):1-14.
  • Paul, G. S. 1997. Dinosaur models: the good, the bad, and using them to estimate the mass of dinosaurs; pp. 129-154 in Wolberg, D. L., Stump, E., and Rosenberg, G. (eds.). Dinofest International: Proceedings of a Symposium Sponsored by Arizona State University. Academy of Natural Sciences, Philadelphia, 587 pp.

We have sometimes neglected tails on SV-POW!, in favour of the more obviously charismatic charms of presacral vertebrae, but every now and then you come across a caudal vertebra so bizarre that it just cries out to be blogged.

One such is this specimen, which may or may not be BMNH R 2144:

Sauropod caudal with co-ossified chevrons, lateral view

Sauropod caudal with co-ossified chevrons, right lateral view

Sauropod caudal with co-ossified chevrons, right posterolateral view

Sauropod caudal with co-ossified chevrons, right posterolateral view

The reason I’m not sure whether this is BMNH R2144 is that I noticed this at the very last minute while visiting the NHM collections to see a different specimen, and just had time to take a couple of quick photos before kicking-out time.  The label on the side of the vertebra has the unexplained number 2144 written on it, so I am guessing this is the specimen number, but I wouldn’t stake my life on it.

(By the way, both these photographs are copyright the NHM.)

The interesting thing about this vertebra is of course that that the chevrons are co-ossified with the centrum — an extremely rare condition in sauropods, in fact unique as far as I know.  As we’ve shown here and here, among other places, the chevrons are usually separate bones from the vertebrae.

This vertebra caught my eye not only because it’s, well, weird, but also because I’d seen it a couple of times in published figures.  It’s in Mantell’s (1850) description of Pelorosaurus, where it appears as figure 11 in plate XXIII, and is considered to belong to Pelorosaurus; and also in Owen (1859: plate V: figs. 3-4).  Owen seems pretty confused about the identity of this element, and in this paper alone assigns it to Streptospondylus (p. 22), Iguanodon(!) (p. 25) and implicitly Cetiosaurus (p. 34).  So what is it?  Well, its provenance is vague in the extreme, so given that it’s not associated with any more diagnostic material, about the best we can say with any honesty is that it’s Sauropoda incertae sedis.

Let’s take a look at those old figures:

Mantell (1850: plate XXIII, fig. 11)

Mantell (1850: plate XXIII, fig. 11)

Owen (1850: plate V, figs 3-4)

Owen (1850: plate V, figs 3-4)

If you’re like me, your first thought was that Owen’s figures are simply mirror images of Mantell’s.  I checked this out by Photoshopping the two sets of figures, flipping them horizontally, scaling and rotating as necessary, and found to my mild surprise that Owen’s figures are in fact redrawn, despite the startling resemblance they bear to Mantell’s.  As it happens, the same is true with the Owen 1859 plate that is the humerus of Pelorosaurus figured by Mantell 1850, and in that case Owen’s figure is rather better than Mantell’s, so let’s give a bit of credit to Owen here.  Most embarrassing for Mantell (not that he cares, having been dead for 157 years) is that Owen’s flipped images seem to be correct (at least, as best I can judge from the photographs I took) — looks like Mantell or his illustrator badgered this up.

So what is going on with these co-ossified chevrons?  As is so often the case, we just don’t know.  Some possibilities: this might be a pathology of an individual, caused either by injury or infection; it might be a natural ontogenetic character in very old individuals; or it might by a taxonomically significant character of a taxon we’ve not yet found — or one that we have found, but don’t yet recognise as being the same thing.  It’s perfectly possible that this is a chevron of Xenoposeidon, for example, but until someone finds a nice complete specimen we’ll never know.

Not much is known about skeleton fusion in sauropods, and most of what’s in the literature is anecdote.  That is set to change, I am pleased to say, as Matt is putting together a paper with his colleague Elizabeth Rega that will survey and interpret the various fusions known in sauropod vertebrae.  I’m looking forward to seeing what they have to say about this vertebra.

References

  • Brusatte, Stephen L., Roger B. J. Benson, and Stephen Hutt.  2008.  The osteology of Neovenator salerii (Dinosauria: Theropoda) from the Wealden Group (Barremian) of the Isle of Wight.  Monograph of the Palaeontographical Society 162 (631): 1-166.
  • Calvo, Jorge O., Juan D. Porfiri, Claudio Veralli, Fernando Novas and Federico Poblete.  2004.  Phylogenetic status of Megaraptor namunhuaiquii Novas based on a new specimen from Neuquen, Patagonia, Argentina.  Ameghiniana 41 (4): 565-575.
  • Mantell, Gideon Algernon.  1850.  On the Pelorosaurus: an undescribed gigantic terrestrial reptile, whose remains are associated with those of the Iguanodon and other saurians in the strata of Tilgate Forest, in Sussex.  Philosophical Transactions of the Royal Society of London 140: 379-390.
  • Owen, R.  1859a.  Monograph on the fossil Reptilia of the Wealden and Purbeck formations.  Supplement no. II (pages 20-44 and plates V-XII): Crocodilia (Streptospondylus, &c.) [Wealden].  Palaeontographical Society, London.

Update

Thanks to Mickey Mortimer for pointing out that this kind of centrum-chevron fusion is known in the theropod Megaraptor.  Here is the relevant figure from Calvo et al.’s (2004) revision of that genus:

Calvo et al. (2004: fig. 5). Caudal vertebrae of Megaraptor with co-ossified chevron

Calvo et al. (2004: fig. 5). Caudal vertebrae of Megaraptor with co-ossified chevron

The strange thing is this comment in the text (p. 569): “Two articulated caudal vertebrae are preserved (figure 5), slightly laterally compressed.  Their centra and the neural arches are firmly co-ossified, as well as their respective haemal arches [i.e. chevrons].  This fusion, not infrequent among dinosaurs, may be pathological.”  Not infrequent?  Is this going on all over the place and I’ve just never noticed it?  Anyone have any more examples?

Update 2

Here is that pair of fused Neovenator caudals with a co-ossified chevron, which Darren mentions in the comments below.

Brusatte et al. (2008: fig. 16d), fused Neovenator caudals with co-ossified chevron

Brusatte et al. (2008: fig. 16d), fused Neovenator caudals with co-ossified chevron

sauropod-enlightenment-480

There is almost too much coolness going on right now. Here’s a brief rundown.

SV-POW! on Tour

Mike and I just got back to our respective homes from the AMNH, where we spent a crazy day in the big bone room and received illumination at the shrine of Barosaurus (above). We came back armed with a gig or so of cool pictures, some of which you’ll see here in the near future and some of which we’ll put off showing you until the relevant papers come out (hopefully!).

Sauropods on TV

When I checked e-mail Thursday night I found out that I had been on TV and not known it. The US-based Discovery Channel spinoff Animal Planet is running an 8 episode series called Animal Armageddon, about the great mass extinctions. I’m in the two episodes devoted to the KT. I expected that they would run the episodes in the same order as the extinctions occurred, but they’re not, which I would have known had I checked the handy-dandy episode guide here (there’s one at the Animal Planet website, too, but all their animated geegaws make both me and my computer nauseated). Why is this relevant here? Because some of my talking-head time was given over to Alamosaurus, which will be on this week’s episode if it survived the cutting room floor. Tune in Thursday, March 5, at 9 PM Eastern/Pacific to find out.

Free Papers That Are Actually Free

Finally, what about the titular free papers? SV-POW! and Tet Zoo regular Ville Sinkkonen turned up some goodies at the Biodiversity Heritage Library and passed them on to me, and now I am passing them on to you:

Holland, W.J. 1915. A new species of Apatosaurus. Annals of the Carnegie Museum 10:143-145. [page] [PDF]

Gilmore, C.W. 1932. On a newly mounted skeleton of Diplodocus in the United States National Museum. Proceedings of the United States National Museum 81(18)1-21. [page] [PDF]

Young, D. 1975. Brachiosaurus, the biggest dinosaur of them all. Field Museum of Natural History Bulletin 46(1):3-9. [page] [PDF]

Jensen, J.A. 1987. New brachiosaur material from the Late Jurassic of Utah and Colorado. Great Basin Naturalist 47:592-608. [page] [PDF]

These are far from the only sauropod papers at the BHL; in fact, they are just the tip of the iceberg. I’m listing these four specific papers because they’re the ones Ville sent and because they exist as stand-alone PDFs. For others that you find, you can either download a PDF of the entire volume in which the paper was published, or use a nifty online PDF generator to make a PDF of just the pages you want. Click the “Download/About this book” tab on the bar above the page viewer and then “Select pages to download”. User-generated PDFs will be hosted by the BHL for a while but not forever. Ville reports that the ones listed above should be good for 30 days (through the end of March 2009); after that you’ll have to make your own. Which is not onerous at all, considering how much literature is being made available for free here. The glass is not just half full, it is running over. Go slake your thirst for obscure sauropod papers, and don’t forget to hoist a metaphorical glass to Ville, or a real one if you get the chance!

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