Last year we began preparation of jackets containing “Popeye“, one of the baleen whales from Carmel Church. As with most of our Carmel Church jackets, there was a great deal of material that was not from “Popeye”, and we’ve been slowly sorting through those remains. A few weeks ago I cleaned up the fragment shown above, which turned out to be part of the periotic bone from a baleen whale.
I knew right away this was not “Popeye’s” periotic, simply because we’ve already recovered “Popeye’s” (and it’s still embedded in the skull, so there’s no doubt about its identity). Periotics are pretty distinctive in baleen whales, so I was hopeful that we could identify this one. That has turned out to be tougher than I thought, because this is a pretty strange periotic, at least compared to the ones I’m familiar with.
This is the left periotic, and the image at the top is in ventral view, with anterior more or less to the right. The posterior process is mostly missing; it should extend off to the left, but only the broken base is present. That base is the first oddity; it’s really long and slender compared to other Calvert Formation mysticetes,
The triangular structure near the middle of the bone is called the promontorium. It includes several openings for nerves that pass through the periotic. But this area is also pretty strange. The promontorium is really large compared to the rest of the bone, and the triangular shape is pretty odd. It’s also pushed over laterally (down in the image), so that the nerve foramina open more ventrally than medially. The promontorium is actually pushed over so far that it’s visible even in dorsal view (the long base of the posterior process is also really apparent in this view):
Finally, while there’s a fairly large anterior process, it has essentially no medial or lateral projections. In most other Calvert mysticetes, at least one of the projections is usually very pronounced, and sometimes they both are. Aglaocetus is an exception, but Aglaocetus doesn’t have any of the other oddities present in this specimen.
So I’m stumped. I’ve not been able to find any described Calvert mysticete that matches this specimen. I’m looking further afield now, checking literature on mysticetes from other localities, but so far I haven’t been able to identify this intriguing specimen. If anyone has any ideas, please speak up in the comments.