My lecture at the Aurora Fossil Museum last Saturday was on squalodont whales. I’ve long had an interest in this group, as I studied them for my doctoral dissertation. The squalodonts (literally, “shark-toothed”) are a primitive group of toothed whales known from the Oligocene to the Middle Miocene. In eastern North America they have been described from New Jersey to North Carolina.
The reconstruction above depicts the largest known squalodont, Squalodon whitmorei, which I named in 2005 (shown attacking the small toothed cetacean Xiphiacetus). Squalodon whitmorei is best known from 2 skulls from King George County, Virginia, although fragments have also been found in Maryland and North Carolina. The holotype specimen (the one that forms the basis for the species) was collected in 1975 from King George County and is stored at the Smithsonian Institution. It is one of the most complete squalodont skeletons ever found:
Squalodonts were a small but significant component of the marine fauna off the east coast in the Early to Middle Miocene. S. whitmorei is only found in deposits that are around 18 million years old, but other species survived until around 15 million years ago before the entire family went extinct. They were the last surviving group of whales with a strongly heterodont dentition, meaning that the teeth were very different shapes from the front of the mouth to the back.