Hairy Museum of Natural History

As long as I’ve got some posts lined up about the Coelophysis population from the Whitaker Quarry at Ghost Ranch, it only seems appropriate to work in this little bit of month-old news: a new sphenodontian, a small, superficially lizard-like reptile related to the tuatara, known from some partial jaws found in a block from the Whitaker Quarry:

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• Whitakersaurus bermani
  Drawing by me, from the day job.

• New Sphenodontian: Whitakersaurus bermani
• Name Means: Berman’s Whitaker lizard.
  (George Whitaker discovered the Coelophysis Quarry where this fossil was found, and David Berman’s fieldwork led to the recovery of the block that contained the type specimen.)
• Relations: Sphenodontian rhynchocephalian
• Location: New Mexico, U.S.A.
• Age: Late Triassic, ~203,000,000 years ago
• Reference: Heckert, A. B., Lucas, S. G., Rinehart, L. F., & Hunt, A. P., 2008. A new genus and species of sphenodontian from the Ghost Ranch Coelophysis Quarry (Upper Triassic: Apachean), Rock Point Formation, New Mexico, USA. Palaeontology 51 (4): 827-845.
• Web coverage:
  • Chinleana: Latest Literature: August 2008.
  • Santa Fe New Mexican: New Species Emerges from Fossil

—Matt Celeskey.

File under: Reptiles, Triassic.

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The catastrophic death assemblage preserved at the Ghost Ranch, New Mexico Coelophysis (Whitaker) Quarry provides a unique opportunity to illustrate a population of Late Triassic theropod dinosaurs. Measurements of 56 individuals at the Quarry suggest a population quite different from those shown in typical illustrations of the “Ghost Ranch Flock.”

Right about now the above text and image should be going up at the PaleoArt Poster Exhibit running alongside the Opening Reception for the SVP Annual Meeting.

Over the past year, I’ve worked with Larry Rinehart to develop skeletal reconstructions of Coelophysis at different growth stages, based on his statistical and allometric studies of the fossils preserved in blocks from the Ghost Ranch Quarry. The preliminary results of that study, and the skeletal reconstructions we’ve developed so far, will be presented during the poster session this Saturday. (For interested readers who aren’t at the conference, check back here when the embargo lifts on Saturday evening for more details.)

One interesting facet that came out of this study was the “demographics” of the Ghost Ranch population—over 40% of the preserved specimens came from small juveniles less than 2kg in weight (like those shown above). Large adults (like AMNH 7223 and 7224, the specimens that most depictions of Coelophysis are probably based on) make up less than 10% of the known specimens of C. bauri. This fits pretty well with the population dynamics of modern crocodiles, and it has some rather dynamic visual implications for artists restoring scenes showing large groups of Coelophysis. I wanted to come up with a quick study portraying this new interpretation of the “Ghost Ranch Flock”

If a population consists of many more children than adults, its a cinch that relatively few Coelophysis hatchlings made it to adulthood. While the case for cannibalism in Coelophysis is still contested, I figured that throwing in an adult grabbing a meal to go in the background would underscore the potential difficulties faced by C. bauri youth. This, along with many other details in the picture, is based on evidence from the NMMNH Coelophysis block—in this instance, some very coelophysoid-looking bones in the coprolites and cololites found aside/inside the skeletons of adults in the block.

—Matt Celeskey.

File under: Dinosaurs, Triassic.

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• 
• Chinlechelys tenertesta
  Life restoration by Mary Sundstrom
  

• New Turtle: Chinlechelys tenertesta
• Name Means: Delicately-shelled Chinle Turtle
• Relations: Basal Turtle
• Holotype: NMMNH P-16697, partial skeleton including pieces of carapace, plastron, neck spine, etc.
• Location: New Mexico, U.S.A.
• Age: Late Triassic, ~205,000,000 years ago
• Info: The fragments that make up the holotype of Chinlechelys include one and one-half dorsal vertebrae that are fused to a thin bit of shell in a distinctively turtle-like manner. Other pieces include a chunk of the plastron, or lower shell, and a piece from the rear of the carapace (upper shell) with bits of rib on the underside. Two spikes of armor were found that may have protected the animal’s neck—similar spikes adorned the necks of more completely known Triassic turtles like the European Proganochelys.
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  The more impressive bits of Chinlechelys on display at the NMMNHS.
• Joyce et al. consider Chinlechelys to be something of a “turtle-in-progress.” Its shell is extremely thin (1 to 3mm thick) and, unlike all other turtles, its ribs do not appear to be tightly fused to its carapace. This fossil could help resolve a long-standing controversy in turtle evolution—did the turtle shell evolve as the ribs widened and fused together into a dome-like shell, or did rows of armor plating in the skin expand until they fused together and integrated with the ribs and vertebrae for support? According to its describers, the thin shell and loosely integrated ribs of Chinlechelys provide compelling evidence for the latter scenario.
• Reference: Joyce, W. G., Lucas, S. G., Scheyer, T. M., Heckert, A. B., and Hunt, A. P., 2008. A thin-shelled reptile from the Late Triassic of North America and the origin of the turtle shell Proceedings of the Royal Society B Published online (FirstCite). DOI: 10.1098/rspb.2008.1196
• Elsewhere on the Web:
  • New Scientist: Fossil Reveals How the Turtle Got Its Shell
  • Chinleana: New “Proto-Turtle” from the Late Triassic of New Mexico
  • Dracovenator: Good News Everyone!

—Matt Celeskey.

File under: Reptiles, Triassic.

Comments on record: (1)

In this case, mine appears to be a Triassic coelacanth:

This was the scene at The Day Job a couple of weeks back, as we unpacked a sculpture for the newly-opened Triassic exhibit. I happened to be wearing the right shirt for the occasion, and my boss David snapped this picture. The piece I’m holding is a fantastic restoration of the freshwater coelacanth, Chinlea sorenseni, about to snap up a school of Synorichthyes. The fish were sculpted by the talented Gary Staab of Staab Studios for the exhibit.

And here’s how the sculpture looks on display, beneath a cast of an fossil Chinlea skull and some Triassic coelacanth bits from New Mexico. The panel is sandwiched between a petrified lungfish burrow and the reconstructed leaves of the enigmatic plant Sanmiguelia. A reflection from the fishtank of Kirby, a living African lungfish, can be seen in the window:

—Matt Celeskey.

File under: Bony Fish, The Day Job, Triassic.

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Today’s the day! Dawn of the Dinosaurs: Triassic New Mexico opens at 9:00 sharp at the New Mexico Museum of Natural History and Science. I (and many other talented staff, volunteers, and contractors) have been working on this exhibit for a couple of years now, and I’m proud (and more than a little exhausted) to say that everyone’s hard work came together beautifully this past week.

I’ll be at the museum for an exhibit poster signing from 9:00 to noon, so if you’re in the vicinity, stop by and say hi.

If you aren’t anywhere near Albuquerque, there’s still a portion of the exhibit tailor-made for you. There hasn’t been any press on this yet, but if you swing by nmstatefossil.org and poke around, you’ll find a wealth of information on New Mexico’s most famous fossil resident, the little dinosaur Coelophysis. The NMMNHS has gotten permission from several authors, publishers, and other museums to distribute much of the primary literature on this Triassic theropod, so digging deep into the site will allow you to access a couple dozen PDFs of technical and popular articles.

The site was put together by Ideum, a fantastic group of interactive developers in Corrales, NM. They also worked with us on an in-hall interactive to interpret our two-ton Coelophysis block from Ghost Ranch:

The touchscreen display features a drag-and-zoom viewer that allows visitors to get a detailed look at the block, a series of highlighted features that can be toggled on and off, video segments of the block’s preparator explaining the features in detail, and an overlay showing the death positions of 7 of the more complete Coelophysis preserved in the block. More info about the interactives can be seen at Ideum’s blog and portfolio site.

And some quick pictures from before I dash out the door:

The skulls of Triassic amphibians. Clockwise from the top: Eocyclotosaurus (cast), Hadrokkosaurus (cast), juvenile and adult Buettneria (fossil), and Mastodonsaurus (cast).

A touchable bonded-bronze cast of the aetosaur Typothorax coccinarum.

Phytosaur skulls (Pseudopalatus buceros) from the Snyder Quarry near Ghost Ranch.

The tiny braincase of the earliest-known mammal, Adelobasileus cromptoni.

—Matt Celeskey.

File under: The Day Job, Triassic.

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