When we started preparing the skull of the baleen whale “Picasso” back in 2009 (above) we ran into a small problem in that there were too many tympanic (ear bones) associated with the skull. We eventually found two pairs of tympanic bullae, but we didn’t know which pair actually belongs to “Picasso”. We were hampered by not knowing which species of whale “Picasso” actually represents.
We’ve also been preparing another Carmel Church baleen whale, “Popeye“. We haven’t gotten very far on “Popeye’s” skull yet, but we did prep the left squamosal. In the image below, “Popeye’s” squamosal is on the left, while “Picasso’s” is on the right in the same orientation:
Given the difference in age (“Picasso” was subadult, while “Popeye” was adult or maybe even elderly), these are very similar to each other. In particular, the mastoid processes caught my attention (outlined in red below):
In both these whales the mastoid is enormous, and makes up a large part of the lateral side of the skull. This is not common in baleen whales, and especially not in those known from the Calvert Formation. This features, as well as a few other details, makes me think that “Picasso” and “Popeye” are the same species, although I’m still not sure what that species is.
But wait, there’s more! Remember the confusion over “Picasso’s” tympanic bullae? There are two different types of bullae that were found with the skull, and we couldn’t tell which one actually belongs to “Picasso”:
It turns out that “Popeye” had a tympanic bulla associated with the squamosal, and since it was preserved essentially in place we know it actually belongs to “Popeye”. That means we can compare “Popeye’s” bulla to those found with “Picasso” and see if it matches either of them. In the image below, “Popeye’s” bulla is on the left:
“Popeye’s” bulla is a very close match for one of the two morphologies associated with “Picasso” (and not the one I originally predicted). So that’s one mystery solved; now to figure out what species these represent!