Oh, Hi, Bohaiornithids!

It's not often that we are introduced to a large new clade of stem-birds*, but a new paper by Wang et al. finds support for just such a thing among the enantiornithes. Named Bohaiornithidae, the family unites a few previously-known similar-looking opposite birds with two brand new species.

Phylogeny of Bohaiornithidae, modified after Wang et al. 2014.

The Strange Bird Dalianraptor cuhe

Type specimen of D. cuhe, originally posted by Andrea Cau

I'm interrupting my regularly scheduled upcoming blog posts to bring some attention to a little-known Jehol bird: the strange 'jeholornithid'-grade species Dalianraptor cuhe.

D. cuhe has spent the last several years as a species in obscurity, even among most paleontology enthusiasts. I recall my first glimpse of the type specimen, wondering over the seemingly-complete remains of an "undescribed possible dromaeosauird" in a low-res photo posted online in the early '00s. I can remember saving the image to my reference folder, hoping that one day I'd be able to update the file name. It's a fascinating animal, but... is it real?

Release the -- Nah. Forget It.

Above: Shonisaurus, favorite paintbrush of giant mythological cephalopods.

In a move that should surprise no one, media outlets have picked up and are running with possibly the stupidest, most blatantly ridiculous scientific "discovery" since the Cambrian mini-men.

Let's break this down. There is a bonebed consisting mainly of Shonisaurus vertebrae which are interpreted as having been deposited in deep water. In some odd twist of fate, the disarticulated vertebral columns of these elongate giant ichthyosaurs were (somehow!) fossilized in long rows. A reasonable person would look at this and think, "it's almost as if vertebrae are stacked in rows inside the body or something."

An unreasonable person, like paleontologist(?) Mark McMenamin, would look at this and think "A sentient giant squid arranged these vertebrae like that in order to create a self portrait of its tentacles!"

I'm sorry you had to subject your brain to that hypothesis.

How such a travesty of logic made it into the abstracts of the 2011 GSA Annual Meeting in Minneapolis, I don't know, but if the scientific publication process works at all, it will not make it through peer review in a real journal. But, of course, that won't stop the media from credulously reporting every word as "new science" because, hey, everybody likes a good "Release the Kraken!" headline.

Most disappointing is that even Science Daily, usually pretty good with the science reporting, ran this story without even a hint of skepticism. Not even a single quote from another scientist to say "um yeah, in case you didn't read what you just wrote, this is obvious BS." For shame.

The Ashdown Maniraptoran

As you may have heard by now, Darren Naish and Steve Sweetman have described an incredibly small, yet apparently adult, cervical vertebra of a maniraptoran dinosaur from the Wadhurst Clay Formation. My first reaction upon seeing pictures of this nice little water-polished bone was "that is effing adorable," followed by "I need to restore this despite the fact that we can have no clue what it looked like." So I did, and the result is shown above (and on my deviantArt page). Let me emphasize again: this is a *highly speculative* restoration of the so-called Ashdown maniraptoran. Darren did a great job of discussing the new paper at TetZoo, so I won't go into details here.

While it is entirely speculative, based as it is on a single bone, it is possible to make some educated guesses about life appearance. Naish and Sweetman note several characteristics of the vertebra that are similar to oviraptorosaurs. However, it is from the early Valenginian age, about 140 million years ago. This is nearly 20 million years earlier than the oldest known definitive oviraptorosaurs, Caudipteryx and Protarchaeopterx. So, I essentially restored this as a very small protarchaeopterygid-grade animal, hence the short tail and tightly-folding wing feathers (oviraptorids could fold their wings more tightly than even many early birds).

There is also some influence from scansoripterygids, given its small size (and as a slight nod to GSP's interpretation of Epidexipteryx hui as a basal oviraptorosaur). Naish and Sweetman point out that the large neural canal of the vertebra is a characteristic of Avialae, but that it may also be a more general size-related character. The scansor influence is found mainly in the shape of the skull and the large procumbant teeth, but those these are the characteristics which are shared by early oviraptorosaurs anyway, and so allow extra wiggle room should it turn out to be closer to avialans. I made the legs quite long compared to the ratio seen in its larger possible relatives, and made the foot fairly large (to better emphasize the diminutive size). The longer legs would, I reckon, help escape hungry mammals, lizards, and whatever else was preying on tiny maniraptors.

Finally, the coloration is fairly drab and cryptic (inspired by small modern birds that spend time hiding in undergrowth) and I chose yellow hues to indicate a bit of an omnivorous diet.

So, while it's impossible to accurately depict an animal based on a single bone which we have trouble even assigning to any specific clade, using some knowledge of basal maniraptoran lineages (it is almost certainly a fairly basal member of whichever clade it belongs to, given its early age), we can make some pretty reasonable (I hope!) guesses.

References:
* Naish, D., and Sweetman, S.C. (2011). "A tiny maniraptoran dinosaur in the Lower Cretaceous Hastings Group: evidence from a new vertebrate-bearing locality in south-east England." Cretaceous Research, 32: 464-471.

Tyrannosaur Tooth Count

Making the rounds right now in the media is a story about a newly described, well-preserved baby Tarbosaurus bataar that helps shed some light on the way tyrannosaurs grow, as well as touches on lingering controversies. Plenty of other blogs have already covered this, so here's a link to the backstory from Brian Switek at Dinosaur Tracking.

Interestingly, the baby Tarb has 15 teeth in the lower jaw, the same number as adult T. bataar. There has been controversy over whether or not tyrannosaurs reduced their number of teeth as they grew, particularly when it comes to the controversial taxon Nanotyrannus lancensis. Nano is known from two specimens (one is nicknamed "Jane") that, depending who you talk to, might really be simply juvenile specimens of the contemporary Tyrannosaurus rex. The differences cited to separate the two boil down to differences in the braincase (certain braincase changes were demonstrated in the new juvenile Tarbosaurus as well), and the number of teeth. Adult T. rex are usually said to have only about 12 teeth in the dentary, while specimens of N. lancensis have a whopping 17. The new juvenile Tarb suggests that in at least some tyrannosaurs, the tooth count is not drastically reduced during growth from juvenile to adult. However, as the authors caution, this same pattern may not necessarily hold true for other tyrannosaurs, even very close relatives.

And, the same pattern does not hold true for the very closely related T. rex. Also making the blog rounds these last few days has been this video of Jack Horner's talk at TEDx in Vancouver (thanks to David Orr at Love in the Time of Chasmosaurs for posting the video link!).



Here Horner gives the basics of his theory that dinosaurs are oversplit, not in the subjective taxonomic sense, but in the more objective biological sense that specimens that could be shown to belong to one species actually represent juveniles of other species. You've all heard the details before, but towards the end he shows a slide (reproduced above) that is pretty damning to the crowd who support the validity of N. lancensis. In fact, adult specimens of T. rex show a very wide ranging tooth count, and it even appears to correspond with relative size (and presumably growth stage. If anything, the number of teeth seen in N. lancensis specimens are only one or two teeth outside the range of variation for T. rex proper, a minor variant that can almost certainly be attributed to ontogeny, and not some cryptic species of giant tyrannosaur lurking in the Lancian faunas that has so far only been identified by two juvenile specimens, while the very common T. rex is known from no juveniles at all.

Anybody know the tooth count for the "Tinker" specimen, currently held in a private collection?

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.

Quick News: SV-POW & SVP

Last time I reported on the odd case of a crazy new amateur paper on Morrison sauropod diversity, including the naming of a new species of Amphicloelias. I hoped that the SV-POWsketeers would comment on this situation, and they have. Be sure to check out this post and it's two follow-ups, as well as the comments (including comments by one of the paper's authors). The upshot is that "A. brontodiplodocus" has not been published, and the authors claim the current .pdf is an unfinished manuscript, but that they stand by their ridiculous conclusions nevertheless. As far as I know, because the name has only appeared in electronic form which is not recognized by the ICZN, "A. brontodiplodocus" can't even be considered a nomen nudum. It may be a nomen manuscriptum or something.

In more pleasant, mainly non-taxonomic quibbling news, SVP is happening right now! Those of us lucky enough to not be within a few hours drive of Pittsburgh for once in their lives (I kid!) but unlucky enough for that one time to coincide with the biggest paleo event of the year, can follow the interesting stuff in real time on Twitter, thanks largely to the efforts of Brian Switek of Lealaps, who is braving the conference's strict press policy and lack of free wifi to get the news out. Follow @Laelaps for hints about sampling biases, even more new, weird ceratopsians, how Euoplocephalus is over-lumped (early '80s favorite Scolosaurus coming back, I wonder?), and which bloggers are going to the bar tonight.

Triceratops Exists, Learn to Read

Above: "Evil scientists want to kill me!"

By now many of you may have seen the headline on science news sites proclaiming that Triceratops has gone the way of Brontosaurus thanks to Scanella and Horner's new paper which suggests it may have been a sub-adult form of Torosaurus. If you understand the very rudimentary basics of science, you may be thinking, "WTF?"

Unfortunately, it should be clear by now that the vast majority of "science reporters" out there are among the most incompetent people being paid to ostensibly "do" the "job" of "reporting news" "accurately." I've already covered the backstory here. Needless to say, just because Triceratops is a juvenile Torosaurs doesn't mean it no longer exists, and furthermore Torosaurus is the newer name, so the name Triceratops is safe and sound (well, except from the shadowy threat of Agathaumas, but that's a different story). Also, David Orr at the awesome blog Love in the Time of Chasmosaurs has already addressed this failure of journalism and journalistic integrity. So I'll just add a few thoughts because really, this is just getting ridiculous.

You've heard it said before that most mainstream science reporters do not understand any single part of the subjects they're covering, and they can therefore be classed not only as useless, but as actively detrimental to human progress. Let's just accept that and call out a few of these hacks by name, shall we? Here are two articles that came up among the top hits when I typed "''Triceratops''" into Google, and are therefore doing the most damage to intelligence in the English speaking world.

Casey Chan, an apparently illiterate Gizmodo blogger, writes: "Scientists sure enjoy crushing my childhood memory of The Land Before Time (they nixed Brontosaurus a while back). Hopefully they won't delete Triceratops too." Immediately after this is a link to a site explaining why they won't, which Casey either read but did not understand or didn't bother to read at all.

Dan Satherley, 3 News NZ reporter of alarmist half-truths, writes: "It seems however that despite its juvenile status, its popularity with the public means that it'll be Torosaurus that ceases to exist. Horner says Torosaurus specimens will now be considered Triceratops." Yeah. You read right. This directly contradicts the headline. Unlike Casey, above, who is merely a simpleton, Dan read the original report, understood most of it (it's not the fact that Triceratops is popular that it remains valid, it's that it's the older name), and wrote the opposite as a headline in an effort to attract more hits. Classy. This is like beginning a review of the movie Backdraft with the headline "Fire in local theater kills dozens."

I should also mention that DinoGoss is not responsible for any head-desk collision injuries caused by reading the comments in these articles. You've been warned.

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?

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 ;)

In other news... Anchiornis now in full color!

Above: Left - so close, yet so far away. Right: The actual colors of a dinosaur.

Oh man, I was SO CLOSE! And I've been planning a new digipainting of this guy too, but was hesitant to do so figuring the color would be worked out in a few months. You can all thank me for summoning this study with mind bullets. Thanks to Ed Young pointing this out on his blog!

Li et al. 2010. Plumage Color Patterns of an Extinct Dinosaur. Science http://dx.doi.org/10.1126/science.1186290

P.S. How flipping beautiful is this new specimen? Go to hell Berlin Archaeopteryx specimen ;)

Above: Awesomeness.

The White Stripes

Back in August, I posted about a study by Vinther and colleagues looking at fossil bird feathers in an attempt to not only determine color patterns in life, but the actual colors constituting those patterns. That study looked only at Cenozoic birds, but tantalizingly, Vinther and co. promised follow-ups looking at Mesozoic birds and other feathered or proto-feathered dinosaurs.

Well, somebody has beat them to it (though, interestingly, Vinther has responded with skepticism to this newest study which has beat him to the punch though appears to use similar methods, as reported by Ed Young). Specifically, Zhang and colleagues have an online-first paper out in Nature today reporting the presence of melanosomes (pigmentation-bearing cell bits) for the first time in protofeathers. The team looked at Sinosauropteryx, Sinornithosaurus and Confuciusornis, and found pigment in all of them.

This is interesting for a few reasons, not the least of which that children's books can now officially limit their audiences imaginations by saying "no, little Billy, dinosaurs weren't whatever color you can dream of, this one here for example was black with shades of red and white patches thrown in." Firstly, this whole color-patterns-in-dinos thing was (as far as I know) first officially brought up by Nick Longrich at SVP 2002. Longrich pointed out that the thing everybody noticed about Sinosauropteryx (the stripey tail) was not an artifact of preservation, as the describers suggested, but reflected color, in the same way that prehistoric insects and fish fossils can show patterns. Based on Longrich's conclusions, I did the painting of Sinosauropteryx shown above, and this has proven largely correct (I lightened the color a bit to seem lighter browning orange, but the original was pretty close if I may say so!).

Unfortunately, being a Nature publication, this announcement comes with high prestige and itty bitty page count. The authors here promise more detailed follow-ups with more specific color patterns, and presumably Vinther et al. are also still working on their studies. Vinther's objection, which I mentioned above, is that as they had pointed out, really deciphering fossil animal colors requires a thorough understanding of how different pigment structures create color in modern birds, which is barely understood. So new discoveries with modern animals could overturn some or all of this. But, for now, all good paleoartists will reconstruct Sinosauropteryx as red-brown with a striped tail, and if Longrich was right about the rest, a bit of counter-shading.

Interestingly, the Sinosaur the new study uses is an undescribed specimen. In some news reports like this one, it is stated that Sinosauropteryx had only a feather fringe along the back, implying a partly scaly body. Now, other specimens have shown evidence of feathers on at least the lateral torso, but could this new one show evidence of a more Juravenator-type scalation on the legs and tail base (as I also restored above)? We'll see...

Venomous Dinosaurs

Above: Illustration of a Sinornithosaurus skull.

A few of you may remember a little 1993 picture called Jurassic Park. In the film as in the novel it was based on, a point was made of showing how unpredictable cloning extinct organisms could be, and that we would not be able to anticipate all the dangers dinosaurs posed just from their fossil remains. To illustrate this, author Michael Crichton invented the idea that the basal theropod Dilophosaurus was venomous. This was, of course, completely fictional and only present to make a philosophical point. There is no evidence whatsoever that this dino had venom, let alone could spit it like a cobra, let alone had a ridiculous display like a rattling frill-neck lizard (added only for the movie).

However, while Dilophosaurus in particular was probably not venomous (and if it was, the late Crichton should be hailed as a prophet for picking that specific dino out of his... orifice), this doesn't rule out the possibility that some dinosaurs were. Poison or venom of come kind exists in a wide selection of modern vertebrates, from amphibians, to lizards (like the gila monster and Komodo dragon) and even birds such as the Hooded Pitohui, which is very aptly named, as the neurotoxins in its feathers cause predators to promptly spit it out.

There has in the past been some goss to the effect that we have evidence for venomous dinosaurs (the difference between venom and poison: poison is ingested or absorbed from prey to predator, venom is injected from predator into prey). A 2 cm long tooth with a longitudinal groove, reported from Mexico in 2001, was suggested to come from a venomous theropod.

Those grooves, which are actually present in most theropod teeth to some extent, are the issue of a new controversy over a paper on the Chinese dromaeosaurid Sinornithosaurus, which we've covered before regarding it's hind wings, or lack therof. A new study looks at the unusually positioned gooves on sinornithosaur teeth, and speculates that these could have delivered venom. The researchers even identify an opening in the upper jaw bone where the venom gland may have been. (left: Sinornithosaurus by FunkMonk. Licensed.)

This is exciting stuff, but take it with a grain of salt. Ed Young does a good job covering the situation at his blog. Basically, it's entirely possible that the grooves are simply features typical of other theropods. Many animals have grooves on their teeth to negate any suction that would occur when pulling the tooth out of flesh. However, Young also reports that Bryan Fry, who discovered the venom of Komodo dragons, has stated that grooved never occur on the posterior side of the tooth surface except in venomous animals, which sounds pretty convincing.

The authors of the new paper cite the length of the grooved teeth as evidence that they were "fangs", but it really just looks like they're out of socket, the way many theropod skulls are mounted in museums. T. rex famously have 6-inch teeth, but that includes the roots. Really, only 2 or three of those inches would protrude from the jaw. Fossils that have been crushed and distorted are also susceptible to out of socket teeth making the dentition look more formidable (and more fang-like) than it really was.

Above: T. rex mount with teeth dangling out of the mouth like it just finished a brutal hockey game. Photo by Quadell from Wikipedia. Licensed.

Obviously more investigation needs to be done, but famous TV personality Dr Tom Holtz is on record saying he evidence is weak, so let's not be too hasty with conclusions here.

Toro! Toro! Toro!

Above: Ceratopsian skull specimen AMNH 5116. Triceratops, Torosaurus... or both? Read on...

By now, all dino fans have probably heard the buzz on the indicator: Jack Horner and team are working on a paper which attempts to prove that Torosaurus and Triceratops are the same thing, and that in general, growth series in dinosaurs are often misinterpreted as numerous similar species (something that has long been acknowledged in pterosaurs and recently in early birds like Archaeopteryx and, probably, Confuciusornis).

Here's the quick and dirty background: Triceratops was named by O.C. Marsh in 1889 based on a pair of horns and skull roof collected in 1887 from Colorado. Numerous complete specimens followed, making Triceratops the archetypal horned dinosaur with its two long forward-pointing brow horns and single short, forward-pointing nose horn, in front of a relatively short (by ceratopsian standards), solid frill. The frill is notable: most ceratopsians, including close relatives of Triceratops, have long frills with large openings, or fenestrae, in the bone.

Torosaurus was described a few years later in 1891, also by Marsh, based on two skulls. Unlike Triceratops, the Torosaurus skulls had long frills with the standard fenestrae. Its frill was also smooth around the edges: many Triceratops specimens show that they had small, bony scutes adorning the frill's edge, called epoccipitals.

According to Horner's talks at SVP, which he also summarized in an interview on the podcast The Skeptic's Guide to the Universe (available here), those differences are not due to species variation, or even sexual dimorphism as previously hinted. Rather, Torosaurus is nothing more than the most mature growth stage of Triceratops. The paper isn't out yet so all the data isn't available, but presumably Horner will demonstrate based on microscopic bone growth studies that all the specimens currently assigned to Triceratops are not fully mature, and that like modern birds, some secondary sexual characteristics (such as the expanded, chasm-filled frill) pop up quite suddenly at the 'last minute' in the animal's growth, after it has already reached nearly adult size.

Above: Diagram of a 'classic' Torosaurus skull. By William Diller Matthew, 1915. Public domain.

We can already see heaps of major changes taking place as Triceratops grows. Juveniles have backward curving horns, which completely change to point forward during growth. Remember those epoccipital fringes, the lack of which is so diagnostic of Torosaurus? We already see them becoming reduced from tall, pointed osteoderms in younger forms to smooth and rounded, and finally merging with the frill itself and smoothing out so as to be almost invisible. Indeed, in these oldest individuals, the bone in the center of the frill can also be seen to thin like a man's receding hairline. Given that we already know all of this about Trike's growth, it's not a very huge leap to recognize a long, smooth, holy frill as the next logical step, and those just happen to have been named Torosaurus for 110 years.

The goss has been flying over this online, and a few interesting tidbits have come up. Having grown up in the Northeast US, the most interesting to me concerns the mistaken identity of some specimens of Triceratops. For me, the quintessential Triceratops is the one in the American Museum of Natural History (specimen AMNH 5116). However, as many have pointed out on DinoForum and elsewhere, it's also among the most... well, un-Triceratops like.

Above: Triceratops skull 'classic' vs. specimen AMNH 5116. By Ed T. and Michael Gray (right), licensed.

Compare the images above. On the right is my beloved AMNH Trike. On the left is a 'classic' Triceratops skull. The frill on the AMNH specimen is longer, and lacks epoccipitals. The frill is also tall and back-swept, not flared out to the sides, as in most Triceratops skulls. Not only that, but as you can see in the image at the top of this post (which is a more contrasty view of the same AMNH skull), almost all of the frill has been restored in plaster to conform with what a Trike should look like. There are significant gaps in the middle of the frill entirely filled with plaster... exactly where the fenestrae of Torosaurus go. If Torosaurus and Triceratops are indeed separate species, the AMNH Trike is no Trike at all... it's a Torosaurus in disguise!

Thankfully, it's more than likely that there is no such thing as Torosaurus, any more than there was a Brontosaurus. It's all Triceratops baby, and we can conclude that this famous last of the ceratopsians was indeed last, the only one of its kind in the Lance and Hell Creek Formations that date to the very end of the Mesozoic era.

But... wait... isn't there another named ceratopsian from the same time and place? Named BEFORE Triceratops?? If there was only one Lance/Hell Creek ceratopsian, then Torosaurus get sunk into Triceratops as a synonyms. Does Triceratops then have to be abandoned in favor of... Agathaumas!?

Above: Painting of Agathaumas by Charles R. Knight, 1897. Public domain.

Dun dun duuuuuun!

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...?