Three Days In New Mexico, Part 1: I Wonder Who Reviewed The Typothorax Paper?

Bill and I were in Albuquerque this weekend for the second meeting of the Colorado Plateau Coring Project. The CPCP is a project spearheaded by Paul Olsen to drill for cores from the Colorado Plateau (the current focus is early Mesozoic strata). Amongst other opportunities, this trip also afforded to opportunity to get a peek at a couple Typothorax specimens on display in the New Mexico Museum of Natural History and Science.

The aetosaur Typothorax coccinarum is of obvious personal interest to me, having been the subject of my master’s thesis (Martz, 2002). I described the material collected by Charles Camp from Canjilon Quarry in the Petrified Forest Member of northern New Mexico, which consisted of disarticulated but associated skeletal material (mostly osteoderms). I figured out, as best I could, which regions of the body particular osteoderms came from by using patterns of variation in articulated carapaces of other aetosaur taxa. Bill and I refer to this as “positional analysis," which Rob Long and Karen Ballew began in their landmark 1985 paper, but which I fleshed out a bit for Typothorax.

The New Mexico Museum of Natural History and Science has excavated TWO articulated Typothorax skeletons from the Bull Canyon Formation of New Mexico. The first (which was briefly described by Hunt et al. in the 1993 Global Triassic volume) was accidently destroyed while being molded, but they were able to get one good pull off the mold which was used to make the bronze on display in the Triassic hall at the NMMNHS.

The second specimen was recovered more recently. Although not as complete as the first specimen, it was highlighted in a recent newspaper article in which peculiar spikey osteoderms on the underside of the tail were speculated to represent “claspers.” This specimen is currently on display in the NMMNHS, and a description is allegedly in press. Neither Bill nor I remember being asked to review the manuscript, which is a little odd since we are sometimes considered “experts” on the subject of aetosaurs.

From Paleo Errata

Anyway, it is a fairly impressive specimen. I’m not going to discuss the specimen as it is still unpublished, but I retract my suggestion on Bill’s blog that the spiky osteoderms are misplaced caudal lateral osteoderms; these are clearly right where they ought to be, and the “claspers” are clearly osteoderms on the ventral side of the tail, as alleged by the authors quoted in the article. I look forward to seeing the description, since it will be a while yet before I get around to publishing a detailed description of the Canjilon material. Both NMMNHS specimens will prove invaluable for testing my positioning of osteoderms, and for clarifying the position of weird osteoderms whose positions I could only speculate upon.

Since Bill has been delinquent on posting my life reconstructions of the Chinle fauna, here is Typothorax. It took me about three tries to do a life reconstruction that worked, for reasons I’ll discuss when the paper on the NMMNHS paper comes out.

From Paleo Errata

Naturally, I fully expect that any observations I made in my thesis which were not previously published will be credited to ME, and I can get extremely unpleasant when this expectation is not met.

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