Wednesday, 10 July 2019
OLIGOCENE FOSSIL WHALE VERTEBRAE
These lovely water worn specimens are difficult to ID to species with certainty but may be from an early baleen whale. Found amongst the beach pebbles on the Olympic Peninsula, they are likely cetacean and very likely baleen as this area is home to some of the earliest baleen whales in the Pacific Northwest.
In 1993, a 27-million-year-old specimen was discovered in deposits nearby that represents a new species of early baleen whale. It is especially interesting as it is from a stage in the group’s evolutionary history when baleen whales transitioned from having teeth to filtering food with baleen bristles.
Visiting researcher Carlos Mauricio Peredo studied the fossil whale remains, publishing his research to solidify Sitsqwayk (pronounced sits-quake) cornishorum, in the annals of science history.
The earliest baleen whales clearly had teeth, and clearly still used them. Modern baleen whales have no teeth, and have instead evolved baleen plates for filter feeding. So when did this evolutionary change occur and what factors might have caused it?
Traditionally, paleontologists have sought answers about the evolution of baleen whales by turning to two extinct groups: the aetiocetids and the eomysticetids. The aetiocetids are small baleen whales that still have teeth, but they are very small, and it remains uncertain whether or not they used their teeth.
In contrast, the eomysticetids are about the size of an adult Minke Whale and seem to have been much more akin to modern baleen whales; though it’s not certain if they had baleen. Baleen typically does not preserve in the fossil record being soft tissue; generally only hard tissue, bones & teeth, are fossilized.