SVP 08: Paleo-Bloggers
So, I’m now back from Cleveland and this year’s meeting of the Society of Vertebrate Paleontology, five days full of museum tours, technical sessions, poster presentations, and all kinds of incredible people with a passion for paleontology: scientists, students, professors, preparators, merchandisers, artists and avocationalists. And, as seen above, a select subset running through all those groups, the bloggers.
Julia Heathcote, of The Ethical Palaeontologist, did a fantastic job organizing a PalaeoBloggers’ Lunch at this year’s SVP. I met some people whose work I’d known for several years, and a few new folks who I’ll be adding to the blogroll soon. They are:
Top row (left to right):
Bottom row (left to right):
Thanks are also due to Julia’s husband Paul, no stranger to the world of blogging, who took the group photos for everyone.
I’ll post some more stuff from the meeting later this week, but be sure to check out Alton and Zach’s blogs in particular for some excellent summaries of their experiences in Cleveland.
—Matt Celeskey.
File under: Webbery.
Comments on record: (5)
Growth and population of Coelophysis: our SVP poster
As previously mentioned, today our poster on the growth, allometry, and age/size distribution of Coelophysis bauri goes up at SVP.
I’ll write up more about my contribution to this in the next couple of days, but for now, I’ll repost the abstract below:
We statistically extracted size (= age) classes from Coelophysis bauri metrics. Using these size classes, we generated a hypothetical growth curve for C. bauri based on femur lengths (N=56). This curve is similar in shape to that of some birds (e.g. Gallus gallus) with the differences largely in time scale, and also to previously reported histologically derived growth data for C. kayentakatae rhodesiensis. Age and mass distributions were then calculated based on the number of individuals in each age class and on femur dimensions. Hypothetically, Coelophysis’ growth rate was very high for the first year. Sexual dimorphism apparently onset between years one and two. After one year growth slowed in the gracile morph while the robust morph is first apparent and grew aggressively for another year; slow growth then continued in both morphs. Robust and gracile morphs probably represent males and females respectively based on their sexual dimorphism index (SDI = robust size / gracile size = 1.34). Both age and mass distributions are of hyperbolic form. Very small ~one-year-olds weighing ~2 kg and ~1.4 m long comprise 40 % of the population, ~11 % are adults weighing ~14 kg and ~2.7 m long, ~2 % reach 25 kg and 3.1 m length.
Our allometry study, based on the 15 suitably complete specimens, agrees with previous studies showing that orbits and hind limbs show negative allometry while skull and neck lengths are positive. Allometric growth constants (this study) relative to total length are: skull length, 1.62; cervical series, 1.31; sacrum, 1.26; caudal series, 0.78; forelimb inc. hand, 1.3; hand, 1.52; hindlimb inc. foot, 0.92; foot, 0.91. Relative to skull length: orbit diameter, 0.28; height at quadrate, 0.22; height at prefrontal, 0.32. The cervical series shows complex allometry (log-transformed data are better fit by a polynomial than linear regression); growth rate being high in juveniles and progressively lower in adults. Thus, relative to adult proportions, juveniles had very short, high faces with large orbits, very short necks, short torsos, long tails, short arms, very small hands, long legs and large feet.
Larry and my other coauthors have agreed to make available for download a PDF of the 2-page, 11 x 17″ handout for any interested parties:
Rinehart_etal_svp2008handout.pdf [1.4Mb PDF]
- Reference: Rinehart, L. F., Heckert, A. B., Lucas, S. G., and Celeskey, M. D., 2008. Growth, allometry, and age/size distribution of the Late Triassic theropod Coelophysis bauri: preliminary results. Journal of Vertebrate Paleontology Vol. 28, suppl. to No. 3.
—Matt Celeskey.
File under: Dinosaurs, The Day Job, Triassic.
Comments on record: (1)
Whitakersaurus bermani
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:
- 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:
—Matt Celeskey.
File under: Reptiles, Triassic.
Comments on record: (0)
Reconstructing a Coelophysis Flock
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.
Comments on record: (3)
Words to Live By
What is a Museum? According to this informed source:
The American Association of Museums crafts one definition to suit its purposes; Matt Celeskey abides by another.
Damn straight.
—Matt Celeskey.
File under: Museumabilia, Webbery.
Comments on record: (0)
