The field jacket containing the lower jaw of the baleen whale “Popeye” also contains a large amount of additional bones. Most of these are from Popeye’s upper jaws, specifically the maxillae and premaxillae. We’ve begun reconstructing “Popeye’s” skull in our lab sandbox, and we can start to see it gradually coming together.
At the top is a dorsal (top) view of “Popeye’s” skull, and the front is to the left. The long bone at the bottom is the left dentary (lower jaw), and the back end of the right dentary is visible at the upper right. The other bones are all parts of the cranium. Below is the same view of “Sinistra’s” skull, with approximately the same areas outlined in green:
The bones on the left are the maxilla and the premaxilla, which is partially covering the maxilla. On the right is the left squamosal, along with part of the parietal and exoccipital (these bones were not in the jacket, but were collected separately during the same excavation). The shapes and proportions are somewhat different because “Sinistra” and “Popeye” are not the same species.
In baleen whales, the maxilla in particular is a difficult bone to prepare, since it’s thin and very lightly constructed. That make the cranium reconstruction go more slowly that with the heavily-built lower jaw. So it may take awhile, but we’re making definite progress on “Popeye”.
