The SEAVP conference is coming up next month, and I’ve been spending most of my time trying to get that organized, including preparing my own presentation. I’m going to be speaking on Eobalaenoptera material that wasn’t figured in the 2004 description of the genus, including both type material and referred specimens.
One of these specimens is the jaw shown above. I’ve already talked about this specimen a few weeks ago, including why it’s only tentatively referred to Eobalaenoptera. I’ve finally finished the major part of the restoration work, and it’s now looking much nicer.
Now that the restoration is completed, another possible oddity has become apparent, as is visible in the dorso-posterior view of the jaw:
The right end of the specimen in this view is the anterior tip of the dentary, and it’s sitting so that it’s oriented vertically. That puts the mandibular condyle (the part that articulates with the cranium) in the foreground at the left. Note that the long axis of the condyle is not oriented vertically, but rather is angled about 45 degrees clockwise relative to the anterior end of the dentary. I’m pretty sure this isn’t due to deformation of the jaw; this seems to be the correct orientation.
This seems to be pretty unusual. Our Diorocetus specimen from Carmel Church has the long axis of the condyle and the anterior end of the dentary oriented in the same plane (that is, they’re parallel to each other). This is also true of Balaenoptera (at least, the minke whale, Balaenoptera acutorostrata). So, whatever this jaw belongs to, it seems to have a somewhat unusual jaw shape.
On top of that, going through the collections this morning I came across fragments of another large jaw from the upper Calvert Formation, but from the Potomac River. It’s almost as large as the Carmel Church jaw, but the shape of the condyle is very different, suggesting that there might be at least one other Eobalaenoptera-size whale in Calvert Bed 14.
This blog is now near (or perhaps over, I’m not sure) 200 entries, which can make it hard to find things in the archives. The iWeb software that I use to write the blog unfortunately doesn’t have a provision for searching or indexing entries. What I’m doing instead is adding some links on the bottom right of the home page to a custom topic index, to make it easier to find past posts. I’ve already added links for Carmel Church, Wyoming, and Solite excavations, and I’ll be adding more as I have time (for example, I’ll be adding basic geology, and visits to other museums). If there are particular categories you would like to see included, put them in the comments and if I can I’ll add them.