Bruhathkayosaurus is Dead. Again.

 Above: Working sketches for a speculative B. matleyi reconstruction by Steve O'Connor. Click here for Steve's final drawing.

I don't know how common this knowledge is, but this is the first I've heard of it so humor me while I mourn the possibility of ever re-assessing the intriguingly large sauropod specimen known as Bruthathkayosaurus matleyi.

B. matleyi was known from fragmentary remains of the pelvis and limb bones found in the Tiruchirappalli district of Tamil Nadu, India. It was first described by Yadagiri and Ayyasami in 1989 as species of giant allosauroid. This classification was widely doubted online, but little follow-up work was ever done. The initial description is widely regarded as exceedingly poor in quality and not much can be discerned about the specimen due to poorly detailed drawings and insufficient text. Tom Holtz has even stated that "the hypothesis that this is no more than petrified wood has not been falsified yet to my satisfaction." However, Mickey Mortimer later noted that the tree trunk hypothesis "is questionable given the non-cylindrical bones preserved such as the ilium. Additionally, Chatterjee has personally examined the fossils, and while he has a bad record of misidentifying taxa, I give him enough credit to not confuse a tree for a limb bone."

Sankar Chatterjee did indeed apparently examine the material and told George Olshevsky and Tracy Ford that he believed it to be a titanosaur, as reported in 1999 here.

Holtz responded to these appeals by noting that "not all units are the Dinosaur Park or the Djadokhta. In some preservation is really, really, really crappy. You might get all sorts of authigenic growth on the fossils, or alteration of the original material. In outcrops like that, it isn't out of the question to be fooled into thinking bone is wood and vice versa, especially from simple surficial appearances. This is why a section of the fossil would help resolve if it is bone or wood." So, there's that. We'll now never be able to take that section.


While B. matleyi was a near-mythical celebrity among "semi-apocryphal gigapods", its legend loomed larger than (published) reality. While most online sources (such as the DML posts quoted above) had long since agreed that the specimen was probably a gigantic sauropod and not a gigantic carnosaur, no actual published reference to the species as a sauropod existed until five years ago (Krause et al. 2006).

And what a sauropod it was, maybe! Obviously with such a paltry footprint on the scientific literature, reliable size estimates for such a poorly described specimen are hard to come by. Luckily, some researchers have done the best they could with the available data and determined that, if B. matleyi was indeed a titanosaur with similar proportions to say, Argentinosaurus, it would have been very large indeed. Matt Wedel over at SV-POW has estimated the size of this animal in life at 139 tons. Mickey Mortimer has estimated its length at up to 34 meters. That would position it as one of the largest species of land animals ever, second only to Amphicoelias fragillimus, possibly.

And now, it appears that B. matleyi has suffered the same fate as its atlantosauroid rival for the record. In the comments at another SV-POW post about semi-apocryphal gigapods, Wedel reports that the type and only specimen of B. matleyi was at some point washed away in a flood.
UPDATE: Thanks to Fabrizio in the comments pointing out a source closer to the horse's mouth. Artist "palaeozoologist" at DeviantArt posted an apparent personal correspondance from Kumar Ayyasami last January, in which he reported that the specimen was lost in heavy rains several years ago. (There's some more discussion of the specimen and the author's publication record here, including the suggestion that Dr. Ayyasami may now be deceased--that is, if you can get past the inexplicable Ali G speak). So it sounds like not only was the specimen poorly described, but nobody had bothered to actually collect it from the field site in the ~15 years since its discovery, and it was (predictably and inevitably) lost to erosion.

Any hope of verifying the stupefying claims about this species' size now seem to be lost. And unlike A. fragilimus, which was described and well-illustrated by a mostly reputable source with no obvious errors, the poor state of the B. matleyi description will forever doom this creature to the realm of dubious claims. After all, given the poor state of the description, it seems possible that a simple scale bar error or other mix-up could have tainted the data, and therefore all of our size estimates.

So here's to Bruthathkayosaurus matleyi, a beast (or possibly, a tree?) that died 70 million years ago, raised its spectral head (or crown?) again for one tantalizing moment and then, like Hitchcock's Ornithichnites, sunk back beneath the earth before we could really learn anything about it.

Scientific Anachronism and why Biostratigraphy Matters

Image: Stegosaurus confronts Tyrannosaurus, from Walt Disney's Fantasia. Such anachronistic views of paleontology could never form the basis of peer-reviewed literature, could they?

A new study (Carbone, Turvey &Bielby, 2011) suggests T. rex could not have been a pure scavenger.

Yeah, I know. This is already the universally accepted position of modern paleontologists. Of course T. rex scavenged if it could, but there is ample reason to think (and ample fossil support backing this up) that it hunted as well. Even the originator of the scavenging thoery, Jack Horner, has basically admitted that he only came up with it as a way to get young people to think critically about their own preconceptions (obviously, he has never met any young paleontology fans. I'd have given up that strategy after I witnessed my first T. rex vs. Spinosaurus debate).

However, as Denver Fowler pointed out on the DML today, drawing an obvious conclusion is the least of the paper's problems.

I recently participated in at least two paleoart discussion threads in which really awesome artists showed off some mind-blowingly fantastic paintings depicting the Jehol biota. I know first hand that both artists are completely on the ball and know their stuff. But both made common errors in the often neglected field of biostratigraphy.

In one, a Sinornithosaurus watches as two Microraptor glide down from the trees. These are two similar animals from around the same time and place. However, there is no evidence that they ever met. All known fossils of Microraptor come from the Jiufotang formation, dated to 120 million years ago, plus or minus 700k years. The youngest Sinornithosaurus fossils are from the upper Yixian formation, dated to around 122 million years ago. The timespan and environment are grossly similar, but 2 million years is still a long time in a world where most dinosaur species, if not genera, don't span more than a couple million years (and the ones that do are probably egregiously over-lumped, like Iguanodon).

Another painting portrayed a Yixian formation scene with Yixian ornithopods and Yixian insects being fed on by Jeholopterus, a pterosaur which lived in the Daohugou biota, in beds dating to at least 150 million years ago, a full 25 million years before the Yixian faunas existed. The error here was probably based on a confused history of dating the formations (old sources placed the Yixian in the late Jurassic), and many sources, both professional and popular, which tended to conflate the various Chinese feather-preserving formations into one amorphous pseudo-fauna.

Artistic depictions throwing together prehistoric animals from disparate times are obviously nothing new. Walt Disney Pictures has done this at least twice, first and most famously in Fantasia (Stegosaurus meets T. rex meets Pteranodon), and later and more flagrantly in Dinosaur (I can't think of any two animals in that movie that were actually contemporaries, and many didn't even live together on the same continent).

This is somewhat excusable when it's done for the sake of art (as long as that art isn't passed off as being scientifically rigorous). But this kind of disregard for, or generalization of, biostratigraphy can creep into science and completely foul up your results.

In Carbone et al. 2011, the authors attempt to calculate the amount of potential carcasses that would have been available to scavenging Tyrannosaurus rex in its environment to make their case. Their lists of T. rex contemporaries are reproduced in part below:

Species and body masses of carnivorous non-avian theropod dinosaurs of Late Cretaceous North America
Dromaeosaurus albertensis
Richardoestesia gilmorei
Richardoestesia isosceles
Saurornitholestes
Velociraptor sp.
Troodon formosus
Chirostenotes elegans
Chirostenotes pergracilis
Nanotyrannus lancensis
Albertosaurus sarcophagus
Tyrannosaurus rex

Species and body masses of herbivorous dinosaurs of Late Cretaceous North America
Parksosaurus warreni
Prenocephale edmontonensis
Ornithomimus velox
Struthiomimus sp.
Thescelosaurus garbanii
Thescelosaurus neglectus
Leptoceratops gracilis
Montanoceratops sp.
Pachycephalosaurus wyomingensis
Edmontosaurus annectens
Edmontosaurus regalis
Edmontosaurus saskatchewanensis
Lambeosaurus sp.
Parasaurolophus walkeri
Edmontonia rugosidens
Ankylosaurus magniventris
Triceratops horridus
Alamosaurus sanjuanensi

The authors state, "our species list is treated as representing a consistent sympatric faunal unit across this region for the purposes of analysis." But they absolutely don't represent that.

If you have even a little bit of a handle on Late Cretaceous biostratigraphy, or the paleoecology of T. rex, you may notice a few problems with these lists. Namely, the fact that they are complete messes, incorporating erroneous or outdated taxonomic assignments or over-generalizations of the geologic column.

This kind of data crunching would require taxa to be broken down on an environment-by-environment basis. That is, in order to be meaningful, all included taxa have to be demonstrated to be contemporaries. Most of the taxa in those lists were not, or can't be said to have been with any confidence.

To be fair, some of the mistakes are due to very new research, some of which has only appeared in abstracts or mentioned briefly in papers. For example, while Edmontosaurus regalis is widely reported from the late Maastrichtian Hell Creek and Lance formations, this is mainly by default, skeletons that are not identifiable to the species level. Ongoing stratigraphic and taxonomic work by Nicolas Campione has shown that E. regalis was actually not a contemporary of E. annectens, and specimens assignable to that species are only known from lower strata. The validity of E. saskatchewanensis, which is from the same stratographic level as T. rex, is pretty dubious. E. annectens is its likely synonym.

Parasaurolophus is known exclusively from the Campanian-age Dinosaur Park Formation, over five million years before the earliest known T. rex fossils. Same goes for Lambeosaurus. While the former was tentatively identified in the Hell Creek by Sullivan & Williamson (1999), this was based on very fragmentary remains that almost certainly belong to Edmontosaurus instead. Montanaceratops is from the St. Mary River Formation, dated to the early Maastrictian and also pre-dating T. rex.

Some cases are even more nuanced. Alamosaurus did coexist with T. rex, but not with many of the other listed species. Current indications are that the southern part of North America during the late Maastrichtian supported a different fauna from the north, comprised many of species which are related to, but distinct from, their northern counterparts. Alamosaurs, for example, did not coexist with Triceratops, but Ojoceratops (assuming they're distinct). It didn't coexist with Torosaurus latus (which the authors apparently lump with Triceratops), but with "Torosaurus" utahensis. Indications are that these beds are a bit earlier than the late Maastrichtian as well, so while Alamosaurus lived alongside Edmontosaurus, it was E. regalis rather than E. annectens.

The carnivores don't fare much better. Most are tooth taxa, like Troodon (another Dinosaur Park critter from the Campanian). While "Troodon" teeth are known from the same beds as T. rex, they're almost certainly not Troodon formosus. The same goes for Dromaeosaurus. However, these are taxonomic issues, not biostratigraphic ones, and don't really affect species count--whatever we name them, there were at least one troodontid and at least two dromaeosaurids present (though the authors erroneously list both Velociraptor and Saurornitholestes, based on the same specimens, first referred to the former and then the later, both incorreclty). Not so for the inexplicable inclusion of Albertosaurus. I can figure out where these other misplaced species came from, but I don't know of any albertosaur remains having been reported from Lancian-age deposits. Anybody? Either way, it's almost certainly an error (as is making Nanotyrannus a distinct taxon, but that's another story).

So you can see why failing to understand which dinosaurs lived together, specifically, can have major implications for actual science. This kind of paper also illustrates why it's a bad idea to keep non-diagnostic genera around as nomina dubia and not sink them into their better known, probably-synonymous counterparts or simply designate neotypes from the good material. These authors avoided pitfalls like including Thescelosaurus infernalis (=T. sp.), Manospondylus gigas (=Tyrannosaurus rex), Aublysodon molnari (=Tyrannosaurus rex), Thespesius occidentalis (=Edmontosaurus annectens), Trachodon mirabilis (=Edmontosaurus annectens), or Agathaumas sylvestris (=Triceratops horridus), but those taxa aren't doing science any favors by cluttering the playing field.

Here's my preliminary attempt to clean up their faunal lists, based on a Lancian-age, northern ecosystem: (updated thanks to additional information provided by Mickey Mortimer in the comments. note that I'm following the authors in not including avialans)
Dromaeosaurinae sp.
Zapsalis abradens
Richardoestesia gilmorei
Richardoestesia isosceles
Troodontidae indet. spp. (multiple species)

Pectinodon bakkeri

Paronychodon sp.

Avimimidae sp.
Chirostenotes elegans

Chirostenotes? sp.
Tyrannosaurus rex (=Manospondylus gigas)
Struthiomimus sedens

Ornithomimus velox

Ornithomimidae sp. (="Orcomimus")

Dromeiceiomimus sp.

Alvarezsauridae sp.

Therizinosauridae sp.
Thescelosaurus garbanii
Thescelosaurus neglectus
Leptoceratops gracilis
Pachycephalosaurus wyomingensis
Edmontosaurus annectens (=Thespesius occidentalis)
Edmontonia schlessmani (=Denversaurus schlessmani)
Ankylosaurus magniventris
Torosaurus latus?
Triceratops horridus (=Agathaumas sylvestrus?)


References:
* Campione, N.E. (2009). "Cranial variation in Edmontosaurus (Hadrosauridae) from the Late Cretaceous of North America." North American Paleontological Convention (NAPC 2009): Abstracts, p. 95a.

Borsti Lives Up to Its Name

[Above: Photo of the type specimen of Juravenator under UV light. From Chiappe & Göhlich, 2010.]

This month, Luis Chiappe and Ursula Göhlich published the first real English-language follow-up paper on the small German compsognathid Juravenator starki (named for its discovery at Stark Quarry near the Jura mountains, which also gave their name to the Jurassic period). You may remember this critter causing a stir when it was first described in 2006. Juravenator was the first non-avialan theropod found from the limestone deposits of Germany and France (which have also yielded Compsognathus and Archaeopteryx) to preserve clear, fairly extensive impressions of its skin and other soft tissue.

The specimen was discovered in 1998, but as far as I know news of this discovery first hit the Internet back in 2001, by way of a German-language news story reported to the DML. The new fossil was nicknamed "Borsti", from the German borstig, meaning "bristly." As some early-release photos show, at this point much of the fossil was not yet prepped, and the bulk of the skeleton was still encased in rock. I remember getting my hands on some photos from the early 2000s showing only the skull exposed, with no trace of soft tissue. Nevertheless, being a compsognathid, scientists fully expected that in life, this animal would have been covered in short, bristly stage 1 or 2 (in Richard Prum's model of feather evolution) protofeathers like its close relative Sinosauropteryx prima.

By 2006, the whole skeleton had been exposed, along with unexpected soft-tissue traces. While limestones from this area are world famous for their preservation of feathers, this is usually limited to the large, vaned feathers present on the wings and tails of aviremigian birds (those with feathered wings like Archaeopteryx). Small theropods like Compsognathus usually preserve very little, if any, soft tissue traces, and even the down-like or proto-feathery body covering of Archaeopteryx is only very rarely preserved, and then only as the faintest wisps in the rock. For this reason, even though the two known specimens of Compsognathus itself didn't preserve any feathers, it wasn't necessarily scaly all over (only a few hints of possible scales have been noted from the tail of one specimen, and even interpretation of those has been ambiguous).

So, when Göhlich and Chiappe described Juravenator, they may have been surprised to find extensive and well-preserved soft tissue surrounding the tail and part of the legs, showing very clear impressions of small, bumpy scales like those known of more primitive theropods and most sauropod and ornithischian dinosaurs. [See photo at right, from Chiappe & Göhlich 2010]. This caused a bit of a scandal, and rendered the name Borsti ironic: here was a specimen which phylogenetic bracketing methods predicted feathers, but the prediction failed. A number of explanations were offered for this. It could be that our phylogenetic analyses were off: that is, Juravenator was not a compsognathid at all, but something more primitive, having arisen before the origin of feathers. Alternately, since impressions were known only from the tail, it could have been feathered elsewhere on its body.

The first suggestion was complicated by the fact that the relationships of primitive coelurosaurs are notoriously poorly understood (some later analyses even found Juravenator to be more advanced than compsognathids), not to mention that the only known specimen came from a juvenile, so testing its relationships are a tricky proposition to begin with. The second suggestion, that Juravenator was only partly feathered, sounded a bit like special pleading given that there was only absence of evidence to go by.

The first hint that the second explanation may have been correct came in a little-known German-language follow-up paper published by the original authors later in 2006 in the journal Archaeopteryx. Apparently, this paper reported that, on closer examination, very faint, thin impressions of some kind of filament were present on the top edge of the tail. But that was all we had to go on until this month, when the complete osteology of the specimen was published.

Examination of the specimen under UV light (performed by H. Tischlinger, one of the co-authors of the paper in Archaeopteryx) has revealed more soft tissue than reported in the description. Additional impressions of scales can be seen under UV on the snout and lower legs, as well as the visible-light impressions on the tail. This new paper confirms the 2006 reports of proto-feather-like filaments on parts of the tail. As expected for these deposits, the feather remains are very poorly preserved, and only the tips are evident. But their size and arrangement seems to closely match those of Sinosauropteryx [see diagram at left, from Chiappe & Göhlich 2010]. Additionally, these impressions lie above the level of the clear, in-tact scale impressions. Impressions of internal tissues, including what may be collagen, can also be seen under UV below the scales and between the vertebrae. This makes the standard interpretation of the filaments as frayed collagen fibers by the birds-are-not-dinosaurs crowd pretty much impossible.

So what does all this mean? Clearly, the second explanation for the surprisingly "featherless" Juravenator seems to have been correct. As the authors note, it's possible that at this early stage of evolution, feathers and scales co-existed across the body of dinosaurs like Juravenator, and possibly even Sinosauropteryx and Dilong, where no scales are preserved but feathers are still found only in certain parts of the body. So far, this kind of co-existence of widespread scaly skin with fringes of feathers has only been known in the ornithischian Psittacosaurus but, they point out, it's not inconsistent with theoretical models of feather development and evolution. [Accompanying image: my life restoration of Juravenator starki from 2006. I'll have to update this to reflect the position of filaments on the tail.]

Of course, it is also possible that explanation #1 is also correct. The authors noted that compsognathids have sometimes been found to be an evolutionary grade, not a natural grouping. In studies which have found a natural, monophyletic Compsognathidae, only a few species (usually of Compsognathus, Sinosauropteryx and Huaxiagnathus) have been included in the analysis. More testing, with more included taxa, are needed to suss out where on the dinosaur family tree other supposed compsognathids belong.

References:

Goehlich, U.B., Tischlinger, H., and Chiappe, L.M. (2006). "Juravenator starki (Reptilia, Theropoda) ein nuer Raubdinosaurier aus dem Oberjura der Suedlichen Frankenalb (Sueddeutschland): Skelettanatomie und Wiechteilbefunde." Archaeopteryx, 24: 1-26.

Chiappe, L.M. and Göhlich, U.B. (2010). "Anatomy of Juravenator starki (Theropoda: Coelurosauria) from the Late Jurassic of Germany.Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 258(3): 257-296.

Brontodiplodocus

Above: "Ah love filter feedin' thorugh mah beak! Om nom nom." Apatosaurus louisae (or not?), photo by Tadek Kurpaski, licensed.

Dan Chure on the DML alerted us to this new, privately published monograph published without peer review (probably?) by an independent fossil digging/selling organization. It concerns a pretty damn remarkable looking bonebed from the lower Morrison Formation with several complete diplodocid specimens of various ages. This line from page 21 pretty much sums it up:

"The traditional approach would have provided us with two new species to add to the Morrison list of sauropods. Instead we employed a novel approach by attempting to fit previously reported Morrison fossils within the context of the A. brontodiplodocus sample. The results are astoundingly radical by comparison with previous studies."

I don't know what to say about this paper. It wouldn't surprise me THAT much if something like this were true but... really? Really guys? Fingers crossed that SV-POW or some some other sauropod experts take a look at this bad boy, though the stigma concerning privately held specimens may simply prompt everyone to ignore it. This is what Mike Taylor suggested on the DML, since he (correctly) pointed out that the hypothesis of the paper (all Morrison diplodocids are congeneric) is essentially unverifiable as long as the specimens are in a private collection and haven't been described in a peer-reviewed paper.

As it was independently published, questions about the newly named taxon's validity have been raised. But, really, is this any different from what Cope and Marsh were doing back in the 19th Century? If anything, cheap and easy publication has simply brought us back to those Wild West days of do-it-yourself science, spurious results and all.

Taxonomy aside, the baleobiological conclusions in this thing are... just... fascinating. and probably will NOT help the author's case.

You can read the pdf here:

Galiano, H. and Albersdorfer, R. (2010). "A new basal diplodocid species, Amphicoelias brontodiplodocus, from the Morrison Formation, Big Horn Basin, Wyoming, with taxonomic reevaluation of Diplodocus, Apatosaurus, and other genera." Dinosauria International, LLC. 44pp.

Tall Tail

This may be old news for those who attended last years SVP meeting, but news of this is (to my knowledge) breaking for the first time online. Matthew Herne has finished a complete osteology of the Australian ornithischian Leaellynasaura, abstract here: http://www.vertpaleo.org/meetings/SVPProgramAbstracts09WEB.pdf.pdf

A few surprising things here. First, Leaellynasaura is traditionally called a hypsilophodontid, or at least basal ornithopod. This study finds that it's even more basal among ornithischians, even sharing some characters with thyreophorans, so it's best placed as a basal genasaurian. Next, the tail lacks the distinctive lattice of ossified, stiffening tendons found in members of many ornithischian clades. Instead, the postzygapophyses of the tail are greatly expanded relative to other members of this order, which may have helped stiffen the back half of the tail.

Most surprisingly, the tail itself is apparently ridonkulously (technical term) long. Leaellynasaurua has over 70 tail vertebrae, more than any other ornithischians save some hadrosaurs, but more astounding is the total length of the tail, which made up 75% the total body length, being three times longer than the torso, head and neck combined. Why such a long tail? One idea floated by Dann Pigdon on the DML today is that if Leaellynasaura had a covering of filamentous feather or fur-like integument (as seen in Psittacosaurus and Tianyulong), it may have been able to use its tail for warmth during cold antarctic nights, wrapping the tail around the body like an arctic fox. It may have also been useful for territorial signaling or mating displays, especially if (as in most animals with filamentous or feathery coats) it could puff the tail up to an apparently larger size by raising its hackles.

I couldn't help taking a break from my Yixian field guide series to try restoring this hypothesis, and the results are above. Can't wait to see this paper officially in print!

Eye-Witness Paleoart

Above: A more speculative take on Genyornis by somebody (Nobu Tamura) who has never seen one in person. Licensed.

As noted on the DML, the ABC is reporting on a pretty awesome find:

http://www.abc.net.au/news/stories/2010/05/31/2913350.htm

That there is some Aboriginal rock art depicting the long-extinct Australian flightless dromornithid Genyornis newtoni. All paleontological evidence suggests that this bird became extinct at least 43 thousand years ago, based on the dating of eggshells. According to a paleontologist (unnamed in the linked article) who examined the site, the details of the painting match well enough to known Genyornis specimens that it must have been done by an eyewitness, and probably is not a handed-down cultural memory of the bird.

Dan Pigdon on the DML also pointed out that the oldest dated rock art in Australia is 40,000 years old, and that also happens to be the limit of carbon dating, so human art on the continent conceivably could be even older, which would certainly overlap with the fossil range of Genyornis. Either way, this represents some of the earliest evidence of humans in Australia and may have been done near the time humans first arrived there. The art itself is pretty cool, and the animals as depicted look more moa-like than emu-like to me, but of course they're fairly abstract. They also seem to have some kind of banding pattern, I wonder if that represents their coloration in life... The one on the right is smaller and more gracile, maybe a juvenile or a smaller sexual dimorph?

More Non-Dinosaurs! Oh no!

Back to dinosaurs soon, I promise.

I've been doing some research on Nyctosaurus lately for my own web site and toward improving the Wikipedia article. The crest situation always confused me, because many traditional depictions of this pterosaur show it with a low, dorsal keel type crest on the snout, similar to some ctenochasmatoids. The well-preserved skulls of the famous gigantic-crested N. sp., however, don't show this feature, and neither to several other nyctosaur skulls. As it turns out, Chris Bennett, who has been working on a detailed osteology of Nyctosaurus, pointed out on the DML several years back that the "N. bonneri" style crest isn't real, an artifact of crushing mistaken for a crest and subsequently enhanced by preperators.

As for the Nyctosaurus sp. with the head like a sailing mast, older depictions showed it with the back-pointing boom much shorter than the up-pointing spar. However, the fossils of KJ1 and KJ2 (the crested specimens) appear to have broken booms, and Bennett 2003 states that the boom was at least 3/4 the length of the spar. Luckily this meme has taken off among paleoartists thanks to the efforts of Mark Witton, and John Conway updating his famously brilliant paintings of this species.

I've updated my own depiction here, as well as the version I had donated to Wikipedia. Oddly enough, I found the older version in a Flikr photo by mavra_chang accompanying a Nyctosaurus display at the Brazos Valley Museum of Natural History in Bryan, Texas. The version is CC licensed but that requires at least crediting my name somewhere. It's hard to tell if that happened there as the image is partially cropped, but they certainly didn't notify me or ask permission... Don't get me wrong, I'm stoked to have my stuff (however outdated) up in a frigging museum. Just, y'know, a heads up would have been nice.

Non-Dinosaur News: Choristoderan Craziness

Above: Hyphalosaurus by Nobu Tamura. Licensed.

This might be the first post where I deviate from the title of my blog... but this was too good to let pass. As first reported by Jocelynn Falconnet on the DML, here are two new papers that just came out about Hyphalosaurus baitaigouensis (a small, long-necked aquatic choristoderan from the Jiufotang Formation) reproduction:

Ji Q., Wu X.-C. & Cheng Y.-N. 2010. Cretaceous choristoderan reptiles gave birth to live young. Naturwissenschaften 97(4): 423-428.
Viviparity (giving birth to live young) in fossil reptiles has been known only in a few marine groups: ichthyosaurs, pachypleurosaurs, and mosasaurs. Here, we report a pregnant specimen of the Early Cretaceous Hyphalosaurus baitaigouensis...

and:

Hou L.-H., Li P.-P., Ksepka D.T., Gao K.-Q. & Norell M.A. In press. Implications of flexible-shelled eggs in a Cretaceous choristoderan reptile. Proceedings of the Royal Society B 277(1685):1235-1239.
Flexible, or soft-shelled, eggs are almost unknown in the fossil record, leaving large gaps in our knowledge of the reproductive biology of many tetrapod clades. Here, we report two flexible-shelled eggs of the hyphalosaurid choristodere Hyphalosaurus baitaigouensis from the Early Cretaceous of China, one containing an embryo and the second associated with a neonate.

To recap, Hou et al. have just reported that a specimen of H. baitaigouensis shows they gave birth to live young. Simultaneously, Ji et al. reported the discovery of unhatched H. baitaigouensis eggs.

I love paleontolgy ;)

Imploding Hadrosaurs and Dubious Nomina Dubia

By now, everybody has heard about Jack Horner's attempt to KILL our beloved Torosaurus.

Above: Look out Toro, Horner's coming and he's packing an AK! Photo by Daniel Hendricks, licensed.

Well, I say "our," but I've never really given much of a thought to Torosaurus, beyond my 10-year-old self trying to get the mechanized DinoRiders toy. But some people seem to feel inexplicably attached to this name, often and incorrectly translated as "bull lizard" (it's got big horns, and was ornery like a raging bull!). In reality it means "perforated lizard", in reference to the holes in its frill. And it's not like the animal will cease to exist, it's just the mature, let's say "silver back" stage of Triceratops. Or should we say, Torosaurus is the mature morph, and Triceratops is the immature morph, of Agathaumas. As I mentioned before, Agathaumas specimens lack diagnostic characters in the context of an environment with multiple taxa from which it must be distinguished. But if there's only one ceratopsian in town, the identity of those generic-looking postcrania is narrowed down to one option, and it's no longer a nomen dubium.

Above: Dear E.D., Please stop naming isolated vertebrae and teeth. kthx. Photo by F. Gutekunst pre-1897, public domain.

Ah, the nomen dubium, or "doubtful name." This is an unofficial* designation given by scientists to names whose type specimens can't be classified because they're too generic. Like many dinosaurs discovered by E.D. Cope, Agathaumas was named based on partial postcranial remains. As more fossils turned up, it turned out that its "unique" postcranial features were actually characteristic of a larger clade, and all ceratopsids have nearly identical torsos and limbs. So Agathaumas lost it's standing as a valid name, because (lacking a skull) it couldn't be determined which species of ceratopsid the bones came from. True, the genus name could have simply been used for all ceratopsid species with this type of postcrania, but modern taxonomists don't roll that way, preferring genera to be mostly monophyletic. For years, Agathaumas remained known as a nomen dubium. It probably belonged to either Triceratops or Torosaurus, the only contemporary contenders known from better remains, but since no skull was found with the type specimen, we could never know for sure which one was the junior synonym.

* The ICZN does not officially recognize any such thing as a nomen dubium, and contrary to popular belief, has no rules to the effect that family names can't be based on dubious taxa, etc. Hence Titanosauridae (=Saltasauridae), Hadrosauridae (=Lambeosauridae), Troodontidae (=Stenonychosauridae), Deinodontidae (=Tyrannosauridae), Podokesauridae (=Coelophysidae) Ceratopsidae (=Chasmosauridae) and yes, Ornithodesmidae (=Dromaeosauridae) are all perfectly valid.

That is, of course, unless the number of potential synonyms is reduced to 1. With Triceratops and Torosaurus recognized as one genus, there is no reason to think that the type specimen of Agathaumas and the type specimen of Triceratops don't come from the same species. If and when another genus of ceratopsid is ever discovered from the well-sampled late Maastrichtian beds of North America, this could always be reversed, but for now the default hypothesis must be that only one was present, rather than an extremely common genus with a wide range of individual variation (Triceratops) and one shadowy mystery genus known only from a post-crania identical to Triceratops but hey, maybe it had like 20 horns or something, who knows?

Sarcasm aside, the concept of nomina dubia has become a bit crazy over the years. Jaime Headden has recently been on a mini-crusade to this point on the DML, questioning some pretty well ingrained and yet pretty flimsy concepts of what is and isn't "non-diagnostic". Let's come to our senses and realize that stratigraphic, ecological and temporal considerations also need to be taken into account. Yes, Agathaumas is non-diagnostic relative to, say, Chasmosaurus. But those two were not contemporaries, and barring the use of a time machine, the other ceratopsians that could potentially be synonyms of Agathaumas could not have existed in the same time and place as it did. Except for one, Triceratops, which by rights should go the way or either Brontosaurus (abandonment) or Coelophysis (official conservation).

Above: The dinosaur Rioarribasaurus had its name changed to Coelophysis by mistake. It turns out the original Coelophysis was not only a different species, it wasn't even a dinosaur. The original is now known as Euceolophysis, or "true Coelophysis." Photo by Ballista, licensed.

Which brings me to the promised hadrosaur implosion. Thanks largely to the work of Nicolas Campione, the taxonomy of Late Cretaceous hadrosaurs is finally being untangled after nearly two centuries of confusion. Contrary to conventional wisdom, the short-snouted type species Edmontosaurus regalis appears to be present only in the Campanian Horseshoe Canyon Formation, not the end-Mesozoic Lance, Hell Creek, etc. All the long-snouted "edmontosaurs" in the late Maastrichtian formations can be assigned to either Edmontosaurus annectens (previously Anatosaurus) or the truly duck-billed form Anatotian. Whether or not E. annectens should therefore be kept as Edmontosaurus or re-classified back to Anatosaurus is a matter of personal preference.

Above: The hadrosaur of many names, lately Anatotitan, the once and future Thespesius? Photo by Claire Houck, licensed.

But there's another monkey wrench here. Campione, in his un-published abstracts and talks so far, has been agnostic on the validity of Anatotitan as a separate species. In the past it's been suggested that the "duck-bill" is merely a preservational artifact, a crushed skull. But, there are several specimens that show this feature, and one that appears to be transitional between narrow and duck-snouted forms. On the DML, Greg Paul has asserted that there is only one species of late Maastrictian edmontosaur, and that the flat-billed versions are the mature growth stage. They even fit the pattern of growth seen in the earlier E. regalis populations, reaching the same maximum size, but then also sprouting the duckbill.

So, it looks like Anatotian is about to go the way of Torosaurus. Except, now the newly low-diversity late Maastrictian dinosaur fauna threatens to resurrect another long-dead name. Thespesius is known only from vertebrae. Those vertebrae could theoretically have come from any hadrosaur... if all hadrosaurs were immortal highlanders. In reality, though, there appears to have been only one hadrosaur species in this ecosystem. And in that case, it can have only one name. And that name is Thespesius occidentalis, "western wondrous one." That name is not Trachodon annectens, because I think the type specimen of Trachodon mirabilis is a ceratopsian. But I'm looking into that one.

Above: Some of these teeth may or may not belong to Trachodon mirabilis. From Leidy, 1860, public domain.

To continue crushing the dreams of myself in 1988 and fans of Jurassic Park everywhere, I'll next try to research whether or not Manospondylus is really a nomen oblitum like everybody is assuming (and everyone does simply assume this, because can you imagine if it weren't?). Outlook probably not so good.

The Baddest Dino You've Probably Heard Of

Above: CGI Spinosaurus from Monsters Resurrected.

Yesterday, I covered the first part of the Discovery Channel's night of dinos on December 6th. After Clash of the Dinosaurs, Discovery aired a less-promoted special on Spinosaurus (apparently the first in a series) called Monsters Resurrected: Biggest Dino Killer. According to Tom Holtz, who was interviewed for the show, a second (apparently better, from his POV) special focusing on Acrocanthosaurus will air in the coming weeks or months. The point of this series seems to bring focus to lesser known giant carnivorous theropods.

The "lesser known" conceit was the first in some bizarre choices, pseudo-errors, and misleading narration/imagery to come from this special. Altogether, I can't say it was "better" than CotD, but to me it was heaps more interesting because of all these little quirks, and some very cool paleontologist segments, not to mention CGI sequences that lasted more than 3 seconds apiece.

Above: For the reference, an accurate Spinosaurus head. By Steve O'Connor, licensed.

First, to call Spinosaurus little-known is a bit of a reach, isn't it? The narrator started nearly every post-commercial break segment with a line like "The most terrifying dinosaur you've never heard of." Yeah, Jurassic Park III wasn't as popular as the first film, but isn't Spinosaurus at least among Brachiosaurus in the ranks of well-known second-tier dinosaur stars nowadays? Or is it only among us dino fanboys? But who else is watching this show?

The next thing that struck me was the design of the CGI Spinosaurus. It is pretty darn inaccurate by today's standards. But... it isn't based on today's standards. It's clearly a direct copy of an older, very awesome drawing by Todd Marshall, down to the dewlap, the spikes, and the almost certainly inaccurate croc-like scale detailing. Whether Marshall was a consultant for the show, or they just ripped his design off after it turned up on Google Image Search, I don't know. Anybody know the scoop? Because if he wasn't involve, this is definitely a case of blatant plagiarism.

Above right: Spinosaurus by Todd Marshall, blatantly plagiarized by me from Google Images. Left: Spinosaurus from Monsters Resurrected.

The main inaccuracy in their Spino model is the head. Now that we have decent skull material, we know Spino has a very narrow, thin snout with a distinct kink in the top and a huge rosette of teeth on the robust lower jaw (see accurate drawing, above). This is all thanks to dal Sasso and his team, who were featured extensively in the special (very cool to see) along with a life-sized model of an accurate skull. Does nobody notice the difference? Adding to the confusion, the special also featured segments with Lawrence Witmer in his famous anatomy lab (and Dr. Holtz's segments even super-imposed him into the lab via green screen, according to his comments on the DML!) . Witmer was shown using computer modeling to re-construct Spino based on the type specimens (destroyed in WWII) and with gaps filled in from the related Suchomimus. Unfortunately, the producers don't seem to have realized that the skull Witmer used was a stand-in, and anytime the skull of Spinosaurus was discussed (that is, every 2 minutes), the (very different) skull of Suchomimus was shown. Suchomimus skull also matches the one Marshall probably based his drawing on, so the accurate, dal Sasso restoration as briefly shown ends up looking very out of place.

Above: Not Spinosaurus.

Also bizarrely, the (almost universally accepted) idea that Spinosaurus was primarily a fisher is only addressed briefly at the very end, along with the hypothesis that the sail could be used as a fish-luring shade as in modern herons. The rest of the time, the talking heads like Holtz discuss ways Spino may have dispatched their prey, probably thinking of fish and small/juvenile dinosaurs and other vertebrates, while the animation shows it picking up and eating a small Rugops like corn on the cob! Never mind that the hand articulation would make corn eating impossible for theropod dinosaurs.

The commentary throughout the episode is actually very good, and mostly accurate, as it's coming from the pros, which are given more talk time than in some other specials. However, the animation and narrator talking about how bad-ass the Spinosaurus is are clearly meant to make it look like a bigger, meaner version of t. rex, rather than a giant heron. Don't get me wrong, giant herons would be damn scary, but I doubt they'd be running around eating abelisaur shish kebab and gutting giant mesoeucrocodylians like fish (very gory and kinda cool, don't see that in a lot of docs!). Also, there was a lot of speculation treated as fact. The bite and feeding style of Spinosaurus is based on modern crocodiles, by experts, but it's just speculation, not the basis of studies, and I've already seen people trying to add this to Wikipedia in the mistaken belief that it's been demonstrated scientifically. It's not even really a well-reasoned speculation, as the snout of Spinosaurus itself is more like a gharial than a crocodile. But maybe the expert quoted was thinking of the broader- snouted Suchomimus.

All in all, an interesting, schizophrenic doc, and I'm really looking forward to the Acrocanthosaurus installment, as that's known from much better remains, not to mention footprint evidence of hunting behavior. However, Discovery needs to get the experts to help write those commercial break trivia questions, and provide pronunciation guides--the poor guy kept calling it SPIN-o-saur-us, as in the Spin Doctors.

Oh, and this is two in a row that got the sauropod feet (nearly) right! The show featured Paralatitan, and you could clearly make the hands out as fingerless stumps. SV-POW must be having some effect!

Above: Hooray for sauropod feet!

Dinosaur Sunday: Good + Bad + Ugly

Above: The T. rex has not thought this through.

Last night, the first part of a new Discovery Sunday special aired, Clash of the Dinosaurs--sort of a slightly more rigorous and scientific-sounding version of the horrible Jurassic Fight Club. Hopefully, any DinoGoss fans will know that these types of CGI action-fests are only loosely connected to reality. One of the main criticisms of these shows, often pointed out online by the very experts featured as "talking heads," is that the writer will latch onto any speculative aside a scientist might have tossed around, and then present it in the show as a concrete fact. Apparently, audiences don't want to know about the process of science or that there may be debate (or no solid evidence at all) for some of these hypotheses. It's more exciting if we just know, man!

Anyway, in this post I'll go over a few things I noticed watching the show, informed by chatter on the DML today from some of he scientists featured and what they thought of the show. I'll also talk about the (very cool if very inaccurate in some very weird ways) show that followed (which I hadn't heard about!) all about Spinosaurus.

First, Clash of the Dinosaurs:
This species tried a bit harder than others to illustrate why we think dinosaurs were the way they're portrayed based on anatomical studies. Each CGI model came with a see-through version to show off the bones, muscles, gastric system, etc. While not perfect, they looked ok, though the show seemed to only focus on the brain for most dinosaurs. It also missed a good opportunity to highlight little-known aspects of anatomy, like the air sac system (especially in the sauropod and pterosaur).

External anatomy was even better in most cases. The T. rex looked great, much better than the god-awful Walking With Dinosaurs or slightly less awful Jurassic Park versions. The sub-adult Triceratops were cool looking despite the extra front foot claw, and from what we saw of the ankylosaur, they obviously did their research (hey, Ken Carpenter was one of the talking heads) rather than just giving it a random arrangement of nodes and scutes. The Quetzalcoatlus was decent, about on par with the When Dinosaurs Roamed America version, but it was not only naked but scaly, a complete departure from known science. Nice to see the leapfrog launch and terrestrial stalking papers come to life. However, the wings looked too much like simple flaps of skin, as in a bat. And the "X-rays" and narration gave no indication that they were anything but skin. No mention of the complex system of muscluature, inflatable sacs, etc. that made these structures true organs, rather than dermis.

Above: Nice pycnofibres, dork.

The discussion of Quetz's eyesight is a good spot to illustrate one of the points I mentioned above. The show asserted that Quet could see in UV, following urine trails etc. of its prey on the ground, and that it would have been eagle-eyed, hunting mainly from the air. The reason all this was in the show, is that expert Mike Habib (one of the talking heads) had a quick back and forth with the interviewers, who asked him if its eyesight would be as good as birds. Mike said it was plausible that it would have had similar eyesight to storks and hawks, and that (since it apparently hunted prey on the ground) maybe could have spotted food from the wing. This translated to Terminator-vision and rock-solid factual statements that it could see for miles. Of course, we have no way of knowing, but I would have said that it would be more stork-like than eagle-like, hunting on the ground, not on the wing.

The sauropod segments were especially good, and the show obviously benefited from having Matt Wedel of SV-POW! as a talking head. It did a good job explaining the age segregation of juveniles, and their "flood out the predators with food" reproductive strategy. Even the CGI models of Sauroposeidon were very good, with the correct number of fingers (though the back of the front feet were still elephantine and not concave as they should have been, but they're trying!).

Above: The role of Deinonychus is played by Heath Ledger. Why so serious?

What I can't forgive is the Deinonyhcus models, which while better than usual (certainly leagues better than JFC) still looked like ugly, overgrown lizards rolled in glue with feathers slapped on willy-nilly, very unnatural, with artificially "mean" looking faces (and apparently, Joker makeup for that extra serial-killer punch). The wing feathers were barely visible, and for a while I thought the arms were naked. What's the point of retaining wings for display (as we know for a fact medium-sized dromaeosaurs did) if you can barely see them? Basically, while CGI animators are getting better at following the facts (raptors had feathers), they're not getting the implication (they should look like giant Archaeopteryx, not mini T. rex with fuzz).

Summing it all up is an excellent quote from Tom Holtz (also featured on the show):
"The documentarians often take anything that any of the talking heads speculated about, and transformed these into declarative statements of fact. In some cases this is particularly egregious, because I strongly disagree with some of these statements and believe the facts are against some of these (say, about tyrannosaurid cranial kinesis...) and they present these as facts rather than suppositions."

For the record, on that cranial kinesis point, dinosaurs could NOT flex their jaws open like pythons. Lawrence Witmer, another consultant on the show, has demonstrated this thoroughly in print, but was not given a say on the matter, which is especially bad since it implies all the experts agree with Dr. Bob on this. Really, I imagine the producers must have loved having Bakker as a talking head, since it gave them license to depict all kinds of zany speculation as fact. I owe a lot to Bakker and idolized him as a kid, but I'd hesitate to call what he does 'science' and not 'unsubstantiated speculation to hype science for kids.'

Above: Sauropods... in... space!

One last pet peeve, then stay tuned for Spino. I'd estimate the CGI segments of the show totalled about 5 minutes of footage, with clips repeated over and over and over and over again to illustrate different points. I'd gladly accept lower-quality CGI if we could at least get some actual 'action' sequences that last more than 5 seconds apiece, and it makes me wish they'd bring back cheaper methods, even stop-motion. Some of the pieces showed even more skimping, like the baby Sauroposeidon with Walking With... Dimetrodon syndrome. That is, the hatchlings use the same model as the adults, making it look like they shrunk down, Mario style. Even worse, the Sauroposeidon hatching sequence takes place at night, on a wide sandy featureless field. With no sense of scale, it looks a herd of adult brachiosaurs emerging from the soil on the moon, which is actually pretty cool.

Oh well. At least they didn't put a Suchomimus head on their T. rex, but more on that later...

The Colour and the Shape

Above: Iridescent Peacock feather, from Flickr. A new study shows that patterns, iridescence and even color can be preserved in fossil feathers.

Every dinosaur picture book aimed at kids comes with a disclaimer /slash/ incentive: "We don't really know what colors dinosaurs were." They were often depicted as green and drab, camouflage suited to their 1930s-era stint as lethargic reptilian swamp dwellers. But, the kid's books tantalizingly continue, "they could have been any color, with any pattern, even bright fuscha with purple polka dots!" (I'm guessing these books are to blame for Barney...).

Well, that's mostly true. We now know dinosaurs are more closely related to birds than modern reptiles (and lets not sell those short, many are very brightly colored). Birds have excellent color vision, and often employ bright colors and striking patterns to attract mates. Some artists have taken this concept to the extreme: See the almost day-glo colors employed by Luis Rey. All of this falls within artistic license, though even this bastion of dinosaur mysteries may disappear for some species. Actually, color can be preserved in fossils, and several recent studies have applied this to fossilized feathers, like those found on some dinosaurs.

Above: One of the iridescent feathers studied by Prum and colleagues in the new paper, discussed below. From National Geographic.

Fossils preserving life body patterns or even color are not new. Many fossilized fish and insects have preserved patterning or even hints of iridescence in their wings, shells, and scales. At least one ammonite fossil is even said to preserve the original, blood red coloration, possibly indicating a deep-sea habitat due to similar color in modern animals from that environment.

A new technique has been developed to help determine if color patterns are real or due to preservation. A 2008 paper by Jakob Vinther and colleagues described looking at apparently patterned fossil feathers under a microscope, looking for (and finding) melanosomes, the remnants of pigment present in life. The traditional view held that most fossil feathers which are preserved as dark 'stains' in a halo around the fossil are caused by bacteria, which cover the feathers as they decay. Vinther and colleagues found fault with that interpretation, though. For example, some fossil feathers show both dark and light bands in regular patterns. Why would bacteria only be present in such regular segments of fossil feathers? Vinther reckoned that rather than bacteria, the small nodules associated with these bands and dark spots (seen under a microscope) were pigment cells, and represented the actual dark/light patterning (though not the specific color) that would have been present in the living animal. Vinther and colleagues concluded that in fact almost all fossil feathers are preserved this way.

Above: Figure 1 from Vinther et al. 2008, showing melanosomes preserved in a banded fossil feather.

That's not to say that feathers lacking a dark carbon film lacked melanin in life--further examination is needed. For example, most specimens of Archaeopteryx do not preserve dark, stained feather impressions. Does this mean the feathers were white? No--in fact, close examination shows impressions where melanosomes would have been, but have since been lost or decayed away.

Still, this could have implications for the famous feathered dinosaur fossils from China. Many of these do preserve feathers as dark carbon stains (presumably caused in part by melanin), and do sometimes show a banded pattern. Such banding can be seen in the tail feathers of Caudipteryx. The "ring tailed" appearance of the holotype Sinosauropteryx tail is probably real, given an unpublished study by Nick Longrich and confirmation (via Dinoforum, of course) that the bands match up across both fossil slabs and so can't be an artifact of splitting the rock as originally suggested. Longrich also suggested that the apparent absence of feathers on the underside of Sinosauropteryx doesn't mean they weren't there, but rather that these feathers were white and did not leave a stain in the rock. Whether or not these feather patterns contain melanin is still an open question that, to my knowledge, nobody has really studied.

Above: Sinosauropteryx may have been counter-shaded, with a white belly and ringed tail. Image from a work in progress digital painting by Matt Martyniuk, all rights reserved.

So, we might actually know what kinds of patterns a few dinosaurs had in life, thanks to preservation of feathers and melanin. But what about actual colors? Well, a new study of melanin in fossil feathers (this time from the Eocene Messel deposits of Germany, home of Darwinius) has found that even traces of iridescence and life color can be recovered. In the future, more detailed study of dinosaur feathers might reveal something similar. A few barely-published specimens of Microraptor do have a very beautiful blue sheen to them (see photo above). Preservation artifact, or dromaeosaurid Blue Jays?

Luckily, formal evaluation of the feathered dinosaurs using this technique is in the pipeline. As co-author of the study Richard Prum told NatGeo, "We are eagerly hoping to be able to work on some of the Chinese dinosaur feathers to try to reconstruct the colors of the feathered dinosaurs." So, the days of drawing these dinosaurs with whatever day-glo magenta stripes you like may be over.

Above: Tail feathers of Microraptor specimen TNP0099624, from figure 2 in Xu et al. 2003. Could these show the color in life or iridescence? Future studies will find out.

And does anybody else remember that very old bit of goss from the DML about a Velociraptor specimen with associated feather proteins that could reveal the color...?