Raptorex update

Above: Recon of Raptorex by Todd Marshall, from CBC News.

Quick taxonomic update: Having just gotten the paper, I can comment that Bill Parker's concerns over the name Raptorex kriegsteini (see previous post), echoed on the DML, are based on misrepresentation of the issue by the newspaper reports. At least one news story said that Kriegstein named the species after his parents, so by ICZN rules the species name needs to be R. kriegsteinorum (-orum being the correct suffix for a name honoring multiple people). However, the paper explicitly states that the species is named only for Roman Kriegstein, so the current name is correct. For the record, here's the entire etymology section from Sereno et al. 2009:

Etymology: raptor, plunderer (Greek); rex, king (Greek); kriegsteini, after Roman Kriegstein, in whose honor the specimen was secured for scientific study.

Also, the paper makes clear that, unlike I speculated before, Guanlong, Dilong and friends are still recovered as tyrannosauroids in the paper's cladogram, though more basal than Raptorex.

Raptorex. For serious, that's a real dinosaur now.

Above: Paul Sereno with a model and skull cast of Raptorex, possibly the most ridiculously named dinosaur of all time. Photo from Chicago Tribune by Nancy Stone.

Headline: DeviantArtist Honoured with Dinosaur Name

Well not really, but surely raptorex must be stoked that his (let's face it), fun but pretty ridiculous username is now the name of a real life dinosaur, Raptorex kriegsteini.

The mini-tyrannosaur is from the Yixian ash beds (not the more famous lake sediments that preserve feathers), and is a bit improbable in other ways than its name. It looks like a mini-Tarbosaurus, with short, two-fingered hands and long, running legs, all things expected from a juvenile tyrannosaurid, rather than a (supposed) primitive tyrannosauroid like Dilong or Guanlong. I wonder if this has implications for their position as basal tyrannosaurs--the paper, supposedly released in the online edition of Science today, is nowhere to be found, for my part.

Raptorex also has a sordid past. Apparently, the fossil was smuggled out of China and sold at (where else) the Tuscon fossil show to a private collector for tens of thousands of dollars. The collector, ophthalmologist Henry Kriegstein (whose family name is honored in the specific name of the new dino), had specialists in Utah prep it out of its matrix so he could mount it in his Massachusetts living room. Upon discovering the specimen was not a juvi tarb as advertised, but rather a full-grown individual, Paul Sereno (so that explains the name!) was called in for further advice, and recognized it as an important discovery. Kriegstein soon agreed to relinquish his purchase to science (with a bonus in the form of naming rights, of course. At least he wasn't a big Bambi fan).

In a bit of taxonomic goss, Bill Parker over at Chinleana notes that, as Kriegstein technically named the genus for his parents, not himself (which is frowned upon), the ICZN mandates that the species name needs to be emended to kriegsteinorum, so watch for that change in the future, likely published by George Olshevsky or a similar stickler for proper Latin.

And, of course, Jack Horner has weighed in. In an email to Wired.com, Horner explained that he thinks the small, fleet-footed Raptorex, because it has the same body plan as larger tyrannosaurs, somehow proves that tyrannosaurs evolved into pure scavengers early on, and that the authors are jumping to conclusions in thinking that long, speed-designed legs somehow imply "predator." Keep on keepin' on, Horner.

Oh Giraffatitan, where art thou?

Above: Skull of Brachiosaurus altithorax (right, from Carpenter & Tidwell, 1998) and "B." brancai (left, by Gunner Rias, licensed).

A curious bit of goss, and potential drama?, teased out Mike Taylor and crew at SV-POW.

In recent posts about a new brachiosaurid announced last week, Qiaowanlong (or is it a brachiosaurid? See SV-POW for in-depth coverage), Mike Taylor consistently reffers to the genus "Brachiosaurus" brancai.

The goss stems form use of the quotes. As we all know, when discussing scientific names, the genus and species are always put in italics. The exception to this are nomina nuda, which are names not properly described or coined. Another exception is when a genus and species combo is found to be invalid for whatever reason. For example, the name Ingenia, for an oviraptorid, is preoccupied and has not yet been renamed. But the species name yanshini is still valid. So, when we talk about this species, we might write it as "Ingenia" yanshini to indicate that the genus name is going to change.

Similarly, this same notation is used for species previously assigned to one genus but are no longer considered related to that genus' type, and are pending reclassification under a new genus name. For example, the species "Dilophosaurus" sinensis is probably not closely related to Dilophosaurus wetherilli, so it gets quotes until a replacement name is chosen. This is also the current situation with "Brachiosaurus" brancai. Many people have suspected that this African sauropod is not the closest relative of the North american type species, Brachiosaurus altithorax, given that a B. altithorax skull has been identified that differs from the African species (see photos above), among other differences in skeletal shape and proportion.

So what's wrong with using quotes when talking about "B." brancai? The African version has already been given a new name! In a 1988 paper, Greg Paul coined the name Giraffatitan for a distinct "subgenus" containing the African species. This was later formalized as a genus name, I believe by Olshevsky in his Mesozoic Meanderings, but correct me if I'm wrong.

So wy write "Brachiosaurus" brancai when, if considering this a separate genus, it should rightly be Giraffatitan brancai? I asked Mike about it, and apparently a paper explaining will be coming out in a week or so. The goss at SV-POW for quite some time has been that the SV-POWsketeers favor a separate genus for "B." brancai, but the assumption was always that this would be Giraffatitan. Mike is playing coy for now--is it simply that the authors don't like the name Giraffatitan? Mike says this is the only paper he's seen in which the acknowledgments contain an apology, so it sure sounds like that is close to the truth...

But a valid name can't be rejected simply because an author doesn't like the sound of it. It would have to be argued away on technical grounds. Is the fact that Giraffatitan was originally a subgenus, not a proper genus, coming into play and allowing Giraffatitan to be re-named? Is the apology directed towards George Olshevsky (maybe the authors don't consider his self-publications valid?). I don't know the ins and outs of priority when it comes to subgenera and subspecies. But we'll know shortly...

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...?

PteroGoss

Above: Mark Witton explains why pterosaurs are so cool. Copyright BBC.

Nothing much to report in the way of good goss lately. It's been quiet in the world of dinosaurology... almost too quiet...

But not so if you're also a big pterodactyl geek. This is not PteroGoss but I'll link to a few awesome stories coming out lately...

Eudimorphodon rosenfeldi has been assigned to a new genus, Carniadactylus, in a sweet paper looking at relationships of primitive pterosaurs. The authors also consider the super-weird Raeticodactylus to actually be a synonym of the contemporary Caviramus. Here's the article from Wikipedia.

Mark Witton describes a new species of Tupuxuara, T. deliradamus! That translates as "crazy diamond," making it officially one of the most awesome pterosaur names that could also be a character in a Guy Ritchie film. Mark also sorted out the priority of Tupuxuaridae vs Thalassodromidae, which you can read about at his blog.

In other Mark Witton news, he's the subject of a new series of videos done by the BBC tracking the construction of several giant pterosaur models for an upcoming British exhibition. Check out TetZoo for more.

Above: Sketch of the upcoming outdoor pterosaur models at the Southbank Centre in London, for the Royal Society exhibition. Copyright BBC.

Lastly, today a new paper announced the discovery of the first known pterosaur landing tracks. The tracks suggest they landed like birds, feet-first, flapping their wings to stall before dropping onto all fours.

My Sauropod is Bigger

There is a new record holder for second-longest dinosaur, longest if you only count bones that currently exist. Skip past the long-winded intro if you want to get to the point!

New mounted skeleton of Mamenchisaurus, in Tokyo, the longest mounted dinosaur skeleton in the world. Image by Shiziuo Kambayashi from the AP.

What is it about pissing contests over the largest dinosaurs? Who cares if Spinosaurus is a few metres longer than Tyrannosaurus? Does it really matter which super long-necked, long tailed giant sauropod is slightly longer than its nearest competitor?

Of course it does!

Well not really, but it can be a fun part of armchair paleontology to keep track of these things. I created the Wikipedia article Dinosaur Size to try and help people keep tabs on this issue using peer-reviewed sources (though for a while there a few too many Internet sources were creeping in, but we've put a stop to that).

Now, everyone gets their shorts in a bunch over the biggest theropod, because even though sauropods are nearly always bigger, they're not the ones who will try to eat Jeff Goldblum. This is evidenced by the fact that one of the biggest theropods in terms of sheer mass, Therizinosaurus, is almost always ignored in these competitions because it was probably herbivorous and looked like a giant porcupine goose with a beer belly. However, despite how cool theropods may be (i.e., extremely cool), sauropods are without a doubt the group where we find the largest dinosaurs.

So which dinosaur was largest? Well, define large. Do you mean length, height, or mass? In modern animals, mass is usually what counts. The African elephant is considered the largest land animal, even though the giraffe is taller and the reticulated python is longer. The most massive, and therefore largest, dinosaur known from decent remains that still exist is a bit of a tie game right now. Traditionally, the largest sauropod known is cited as the titanosaur Argentinosaurus, with rational mass estimates ranging between 78 and 83 tonnes. However, several other titanosaurs were about the same size, if not bigger, including Puertasaurus and the horrifically named Futalognkosaurus (note that the official name even includes a misspelling, yikes!).


Scale diagram showing several of the largest dinosaurs discussed in this post. Green: Diplodocus. Orange: Supersaurus. Purple: Argentinosaurus. Blue: Sauroposeidon. Grey: Bruhathkayosaurus. Red: Amphicoelias. Scale bar = 40m. Image by Matt Martyniuk, licensed.

The new goss here though, to finally get to the reason for this post, is that the record for longest dinosaur has changed... sort of (see final paragraph, below). When I was a kid, I was enthralled by the longest known dinosaur according to several of my books, the "Seismosaurus" (earthquake lizard). This monster diplodocid (whip-tailed sauropod) was said to be over 130ft in length. Well, those initial estimates were a little too hopeful, and based on the mis-identification of a tail bone which threw the estimates off by up to 30%. More reasonable estimates place its total length at a mere 33.5m (110ft), and furthermore, it turned out to likely be just a slightly oversize specimen of Diplodocus anyway.

The downsizing of Seismo--er, Diplodocus left the length champion to its cousin, Supersaurus. As the preparation of a fairly complete skeleton nicknamed "Jimbo" by Scott Hartman showed, Supersaurus probably reached a total length of 34m, or 112ft, surpassing both Diplodocus and weight champion Argentinosaurus by a meter or two (in the process robbing the titanosaurs of their clear victory in both units of measure).

However, now a new champion emerges by a neck (I'll be here all weekend folks!). A new specimen of the mega-necked Chinese sauropod Mamenchisaurus unearthed in 2001 was initially reported as the largest of its kind at a respectable, but short, 30m (98ft). However, a surprise came when they assembled a reconstructed skeleton for a new exhibition opening in Tokyo: the specimen actually measures a whopping 35m long, or 115ft, beating out Supersaurus for the title of longest known dinosaur. See photo at top of this post.

Extraordinarily accurate (down to the scales) illustration on Mamenchisaurus by Steve OC, licensed.

That is, if you don't count Amphicoelias. This monster, known from a single partial vertebrae that was 8ft tall and would have been 12 if complete, was very similar to Diplodocus and, scaling up from the same bone in that animal, Amphi would have been at the very least 40m long (131ft) and probably in the area of 120 tons, easily trumping all other contenders in every category: length, weight, and height (read the Wiki I started and wrote most of on Amphi here). So far the only contender to that throne is the even more dubious Bruhathkayosaurus, which is known from a poorly preserved, poorly published, and basically never studied leg bone sometimes thought to be a tree trunk, and even if the size the describers said it was is probably vastly overestimated in published surveys. For now, Amphi is the king, but its smaller cousins with better remains are inching closer.

More On Chewy Hadrosaurs

First, thanks to those who commented and emailed regarding my post on the controversial hadrosaur chewing mechanics paper (see "Nom nom nom"). Vince Williams, lead author of the paper in question, was among those who contacted me about it, and he pointed out an error that stems from (yet again) science reporting that isn't all there.

Above: Underside of the skull of Leonardo, the Brachylophosaurus mummy. By Ed T., from Flikr. Licensed.

My last post reiterated a statement from this MSNBC article, that gut contents of the famous hadrosaur mummy "Leonardo" seem to contradict Williams et al.'s findings, because the plant matter was

a) chopped or sheared, not chewed, and
b) mainly coniferous, indicating that hadrosaurs were browsers rather than grazers.

Well, I checked up on the source that MSNBC used for this information (Leonardo is, despite documentaries on the History Channel, not fully studied and published on yet). That lead me to another MSNBC article on Leo, which appears to state the opposite! From the older, cited article:

• "An analysis of the gut contents from an exceptionally well-preserved juvenile dinosaur fossil suggests that the hadrosaur's last meal included plenty of well-chewed leaves digested into tiny bits."
• "An analysis of pollen found in the specimen's gut region revealed a variety of plants, including ferns, conifers and flowering plants. Although the pollen could have been ingested when the dinosaur drank water, the tiny leaf bits, under 5 millimeters (a quarter-inch) in length, indicate that Leonardo was a big browser of plants, Chin said."

So, the gut contents in question actually would seem to support, at least in part, Williams' findings. Even stranger given the apparent lack of cranial kinesis reported last December. Obviously further study is needed on this...