Short update this week because I’m busy finishing up my projects… one week left!
Check out the other Mongolia Monday posts here.
The season has officially changed here and in addition to preseason hockey (yay!) we’re getting snow here in Ulaanbaatar (boo!). Fun fact, Ulaanbaatar now has a hockey rink, in a shopping mall of all places. Maybe next year I’ll try and organize a beer league…
I’ve finished preparing the mystery specimen, whose identity, of course, is now leaking out to various people. I’ll have to wait for permission before I post anything, but once I can, I have some great images for you (+ a 3D model)! I’ve been working on describing that specimen, but I also finished up re-interpreting some oviraptorid eggs and embryos from Bugiin Tsav.
These eggs were first described in 2008 by Weishampel and coauthors in the Journal of Vertebrate Paleontology. The paper has gone somewhat under the radar, however, despite being the first eggs and embryos from the Nemegt Formation. Part of this was that the style of fossilization makes it tough to interpret the bones, and so they couldn’t be identified to a species of oviraptorid. To make matters worse, we still didn’t really know much about oviraptorid anatomy at that point–the first complete osteology was Balanoff and Norell’s 2012 description of Khaan.
Now that we know more, and armed with a good macro lens, I’ve been able to reinterpret some of the features that puzzled Weishampel et al. First, there’s a lot more of the skeletons than they first interpreted. The best (and smallest) embryo has parts of the skull and a virtually complete skeleton except for the tail. The bones are fairly well ossified too, and some of them have begun to look like adult bones. Two other embryos represent most of a skull and the area around the pelvis, respectively. The skull consists of everything behind the eye and a couple bones from in front as well, which weren’t previously recognized (specifically the nasal). The pelvis is beautifully preserved and has a nearly complete hindlimb as well, missing the foot.
Because I’ve looked at way too many oviraptorosaurs, I was able to pick out a couple extra details that I think help to verify the identity of the specimen. A combination of features made me suspicious… Metacarpal I equal in length to Metacarpal III; big proximodorsal lips on the unguals; broad, short ilium; proximally pinched metatarsal III. Could it be? Yes, I think these may actually be caenagnathid eggs!
I’ll have to verify some of the features and make sure I’m not “pulling a Greg” and calling everything a caenagnathid. But, I approached these specimens as though they were oviraptorids, and I just couldn’t figure out which one had those features, until I stepped back and realized all the weird features are typical of caenagnathids. If I’m right, it will be an exciting reinterpretation!