The whales that we see in today's world can broadly be split into two groups: those with teeth (odontocetes), and those that have baleen (mysticetes) instead of teeth. These two groups share a common ancestor in the Eocene, which had teeth (They looked a lot like the ancient whale skeletons in the Sant Ocean Hall). This insight leads to a question: When, in their evolutionary history, did mysticetes lose their teeth?
Actually, mysticetes still retain the genetic programming for teeth because they have tooth buds while embryos. More precisely, we would say that mysticetes lack the adult, mineralized teeth that their ancestors and living relatives do. When and how mysticetes switched from teeth to baleen has been one of the big questions facing whale paleontologists in the last decade. Several new discoveries of "toothed" mysticetes from Australia and the US have suggested that this transition wasn't simple, and that there were several false starts and evolutionary experiments before true baleen-assisted filter-feeding evolved.
It turns out that the rocks from the time period (the Oligocene, ~23-28 million years ago) that ought to preserve this transition are less abundant than those from nearer in time. In fact, there are only a few places in the world paleontologists can go to hunt "toothed mysticetes," and one of the most productive has been the Pacific Northwest of North America. As a postdoc at the University of British Columbia, I had the opportunity to prospect the Oligocene age rocks of Vancouver Island, which crop out abundantly along the famed West Coast Trail. An incomplete skull of a "toothed" mysticete was described from the island in 1968, but since then, little has been reported formally in the literature. During our reconnaissance work in 2009, we found a lot of fossils, including one that seemed to represent the skull and skeleton of a "toothed" mysticete. But we didn't have the necessary permits (it's located on federal land) or equipment to excavate it, so we left it, but took careful notes and data about its location.
Fast-forward 3 years to this year, when we finally received our excavation and collection permits from Parks Canada. Now, after several months of planning, we're ready to use chartered boats, chartered helicopters, rock saws and a lot of sweat to dig it out, and return it to the Smithsonian for preparation and study before finally being deposited in a Canadian natural history collection. Follow along over the next few days as we update our work live from the field!
Editor's note: read more about the specifics of the excavation on the Pyenson Lab blog and check back with the Ocean Portal for further updates from the field!