During last summer’s Carmel Church excavation we collected a left squamosal fragment from a small baleen whale, which included most of the petrosal (part of the ear); it was the only significant skull material we found on that excavation. Upon retuning to VMNH I cleaned up the specimen a bit and compared the petrosal to others in our collection, and found it to be an almost perfect match to the same bone in “Sinistra“, a specimen of Diorocetus hiatus which was also found at Carmel Church (“Sinistra” is on the left, below, while the new specimen is on the right):
I had hoped that we might find more pieces of this skull when we went back into the same pit last March. While we found quite a few bones, at the time it appeared that we hadn’t recovered any more of the skull. But at Carmel Church we bring everything back, even if it doesn’t look like much at the time. While going through the March 2012 material last week, Kathy and Ray found another squamosal, a right one this time, which was found only a few inches from where the first one was collected. Once they had cleaned it up, it was clear that the two bones were almost certainly from the same whale:
We may also have a third piece, the basioccipital (the bone that makes up the floor of the braincase), but we haven’t finished cleaning that one yet so we’re not sure about its identification.
One of the interesting things about these fragments is that, other than the missing zygomatic processes (which often break off), these bones are broken along sutures. That suggests that the skull wasn’t crushed post-burial, but rather that it fell apart because the bones weren’t fused yet, and that suggests that the whale was a baby. Even the exoccipital-squamosal suture is open; I think this suture closes very early in whale ontogeny, so this may have been a really young whale. This is also borne out by showing the fragments next to “Sinistra” at the same scale (the red-outlined areas on “Sinistra” are approximately the portions preserved in the new whale):
This is a tiny whale! And keep in mind that the petrosal is just as large as in “Sinistra”; the petrosal in whales doesn’t show a lot of ontogenetic variation.
We’ve named this tiny whale “Buttercup”, in honor both of one of the Powerpuff Girls, and volunteer Laura Kellam (to whom we gave the same nickname), who predicted that we would find a whale skull in this particular pit.
We are hoping to reopen “Buttercup’s” Pit this summer, if our Petridish fundraising campaign is successful. We only have 11 days left and are still short of our goal, so if you have not yet pledged please do so!