Sunday, May 24, 2015

The Crane and the Microraptor

A Tetrapteryx. Photo by Charles J. Sharp, CC-By-SA

Quick post on a recent taxonomy fail:

I checked my Wikipedia account this morning to discover that several protobirds had been reclassified. Aurornis, Anchiornis, Xiaotingia, and some microraptorians were now displaying the family name "Tetrapterygidae". I was surprised and a little excited. Had a new four-winged dinosaur been found that, when included in a phylogenetic analysis, resulted in the above grouping? Most of these species are scattered among various lineages of the clade Paraves in all other analyses to date, so it would be quite interesting to find that all of these four-winged dinosaurs actually formed a clade. For example, such a result would suggest that the famous "tetrapteryx" hypothesis proposed by William Beebe in 1915 was wrong, and that these "tetrapteryges" were in fact a side branch engaging in an experiment with four-winged gliding flight. Where was this coming from?

Oh. Sankar Chatterjee. Never mind.

Chatterjee apparently named the family Tetrapterygidae in the new 2015 second edition of his book The Rise of Birds, originally published back in 1997. Chatterjee essentially believes that the key character of flight feathers on the hind limbs is enough to unite these handful of paravians into a clade, and he slots them into a cladogram as the sister clade of Avialae without actually performing any kind of analysis. This is old-fashioned typological classification misleadingly disguised as science, and it was enough to trick at least one Wikipedia editor into buying it and changing the pages  on these animals accordingly.

I'm not sure if this is supported in Chatterjee's book, but the editor also wrote in the discussion of this family how it is named after and supports Beebe's hypothesis when it in fact does the opposite, as mentioned above. If Beebe is right and birds evolved from four-winged ancestors, we should expect to see four-winged species making up a paraphyletic grade around the base of Avialae... which is exactly what we do see, in the traditional classification where the four-winged dinosaurs do not form a single clade (though it's extremely debatable whether or not the short feathered "trousers" of things like Anchiornis can justifiably be called, or even compared to, "wings").

Not only is this "Tetrapterygidae" bad science, it's bad nomenclature. The ICZN, which governs "family" ranked names, is very clear on it's central "principle of coordination". A family name must be named after an included type genus. That means any family named Tetrapterygidae must include the genus Tetrapteryx (Thunberg, 1818), the type species of which is Tetrapteryx capensis, a junior synonym of Anthropoides paradiseus, the South African Blue crane. According to the ICZN, therefore, Tetrapterygidae is a junior synonym of the family Gruidae and can't be used for four-winged paravians. EDIT: Additionally, as I forgot to mention before, any family-ranked taxon that contains Microraptor should be called Microraptoridae, since Microraptorinae already exists.

Ironically, under the PhyloCode, Tetrapterygidae could be considered a node-based clade that contains the species Chatterjee used. This would make it basically equivalent to Eumaniraptora, which also happens to include cranes. Problem solved!

Saturday, May 23, 2015

The Year of the Ceratopsian Ankylosaurs

Life restoration of an advanced stegosaur- I mean an ankylosaur (Ankylosaurus magniventris) by Emily Willoughby,  CC-BY-SA.
When digging into the history of North American fossil interpretation for the eventual next edition of my Beasts of Antiquity series, one thing that I found a bit weird was the constant reference to ankylosaurids and nodosaurids as types of stegosaurs. To a modern reader, this seems off. After all, the group of armored dinosaurs, Thyreophora ("shield bearers"), is divided into two major groups: Ankylosauria and Stegosauria, each with a few well supported subgroups. It makes sense that these close relatives might once have been classified together, and stegosaurs were discovered first, lending them priority of name. But what changed? Neither ankylosaurs nor stegosaurs are particularly large groups (especially the stegosaurs), and it seems odd that 20th century taxonomists would want to raise a group as small as the modern idea of Stegosauria to the level of "suborder".  Why were ankylosaurs eventually spun off, leaving the more primitive stegosaurs behind? I decided to do a little digging to find out.

Monday, April 13, 2015

The American Museum Brontosaur - A History In Pictures

The wooden model used to explore poses for the original
brontosaur mount is now on display beside the
revised mount at the AMNH. Photo by the author.
Here's one more post to commemorate the revival of the name Brontosaurus for the beast formerly known as Apatosaurus excelsus. As I mentioned in my last post, the mounted skeleton of the so-called "Nine-Mile Quarry Brontosaur" at the American Museum of Natural History, while it may or may not actually be a Brontosaurus, is probably the most iconic version of this animal, overshadowing even the archetypal brontosaur skeleton at the Yale Peabody Museum.

This is in no small measure thanks to the efforts of problematic Hitler enthusiast and highly successful paleontology promoter Henry Fairfield Osborn. Osborn became the first curator of the Vertebrate Paleontology department at the AMNH in 1891 and quickly rose to prominence, becoming the president of the museum in 1908. Osborn worked quickly to create a world-class collection of dinosaurs for the museum, both launching his own expeditions to collect fossils for display and making significant trades and acquisitions, such as the collections of E.D. Cope.

Friday, April 10, 2015

The Brontosaurus Club

Brontosaurus excelsus - the triumphant return.
By M. Martyniuk, all rights reserved.
By now, anybody who's interested in paleontology, and their mother, and their great uncle, have probably heard the news: Brontosaurus is back!

Of course, the more technically minded paleo fans will know that Brontosaurus never actually went anywhere. Ever since its first specimen was studied in 1879 by Bone Warrior O.C. Marsh, paleontologists have agreed that the species Brontosaurus excelsus* was unique among sauropods. The question soon became, however, exactly how unique. In 1903, Elmer Riggs decided that it was similar enough to another sauropod species, Apatosaurus ajax, that they should both be placed in the same category of sauropods, and since Apatosaurus was an older category ("genus") name than Brontosaurus, he reclassified the species as Apatosaurus excelsus. However, it was clear even to Riggs that Apatosaurus excelsus and Apatosaurus ajax were different species, and the decision to "lump" them together into one category was always subjective and non-scientific - these kinds of things are a matter of taste only.

Saturday, February 21, 2015

The Evolving View of Stegosaurus

Mounted skeleton of Stegosaurus ungulatus at the Carnegie Museum. The tail, plate, and spike arrangement have been updated in this mount to reflect current thinking following the study by Carpenter (1998). Photo by Perry Quan, CC-By-SA 2.0.
Seeing as how I've been working on restorations of two different stegosaur species this month, I thought I'd write up a quick review of the most famous aspect of these iconic dinosaurs: Their big, triangular plates. For a complete overview of the history and interpretation of Stegosaurus, be sure to see Ken Carpenter's 1998 paper.

Interpretation of the life appearance of stegosaurs has changed several times since they were discovered by O.C. Marsh in 1877. The first stegosaur fossil (belonging to the species S. armatus) were found near the town of Morrison, Colorado, but the specimen was disarticulated and only a few of the plates were preserved. Initially, Marsh thought that these plates played flat along the animal's back, forming a sort of turtle-like shell, or like the tiles on a roof (hence the name Stegosaurus, which means "roofed lizard"). Marsh also initially believed that stegosaurs were aquatic, due to this turtle-like appearance, but also that they would have walked on two legs on land.

Sunday, November 30, 2014

Is Jurassic World Stealing from Independent Illustrators?

Sorry for the clickbait title. The answer is yes. Yes they are.

It's one thing when toy companies do it.

It's quite another when a big-budget Hollywood movie starts stealing the work of independent paleoartists and illustrators for use in their production design.

It started when well-known paleo illustrator Brian Choo posted the following modified production still to his DeviantArt account. The photo in question is fairly low res and comes from the newly opened Jurassic World web site. The still features children using a prop in the movie called a "Holoscape", presumably a kind of interactive computer terminal featuring information about the various kinds of dinosaurs in the park.

Still from Jurassic World, modified by Brian Choo to highlight areas of plagiarism.

Sunday, November 2, 2014

Raiders of Dinosaur Art: Rampant Plagiarism by Toy Companies

Look Familiar?

Greetings, goss hounds!

Last time, I mentioned that Darren Naish, Mark Witton, and John Conway recently published an article on the (shameful) state of  paleoart as used in professional and commercial contexts. This was in reference to toy companies like Safari Ltd., who often produce inaccurate dinosaur figures under the banner of "museum quality" or "paleontologist approved."

Another such company is Geoworld. I'll let their own web site do the talking:

"All models in the Geoworld collection are scientifically accurate museum replicas of dinosaurs or prehistoric animals. Each model is sculpted by expert craftsmen under the supervision of Dr. Stefano Piccini, geologist and paleontologist, to ensure the correct shape, posture and proportions. Geoworld products are paleontologist and geologist approved!"
That sounds very nice, except for one unsettling fact: Nearly every figure in the Geoworld dinosaur series is blatantly plagiarized from independent paleoartists. Not only that, but often the actual original art itself is reproduced with a few minor tweaks and printed on the info cards that accompany each figure. No credit, let alone payment, has been given to any of the offended artists.