Olympicetus thalassodon is one of several that are helping us understand the early history and diversification of modern dolphins, porpoises and other toothed whales.
Olympicetus thalassodon swam along the North Pacific coastline around 28 million years ago (Oligocene epoch).
“Olympicetus thalassodon and its close relatives show a combination of features that truly sets them apart from any other group of toothed whales,” said Dr. Jorge Velez-Juarbe, a paleontologist in the Department of Mammalogy at the Natural History Museum of Los Angeles County.
“Some of these characteristics, like the multi-cusped teeth, symmetric skulls, and forward position of the nostrils makes them look more like an intermediate between archaic whales and the dolphins we are more familiar with.”
In addition to Olympicetus thalassodon, Dr. Velez-Juarbe examined the fossilized remains of two other closely related toothed whales.
The specimens were found in the Pysht Formation, exposed along the coast of the Olympic Peninsula in Washington State, the United States.
Dr. Velez-Juarbe found that Olympicetus thalassodon and its close kin belonged to Simocetidae, a family so far known only from the North Pacific and one of the earliest diverging groups of toothed whales.
Simocetids formed part of an unusual fauna represented by fossils found in the Pysht Formation and which included plotopterids (an extinct group of flightless, penguin-like birds), the bizarre desmostylians, early relatives of seals and walruses, and toothed baleen whales.
Differences in body size, teeth and other feeding-related structures suggest that simocetids showed different forms of prey acquisition and likely prey preferences.
“The teeth of Olympicetus thalassodon are truly weird, they are what we refer to as heterodont, meaning that they show differences along the toothrow,” Dr. Velez-Juarbe said.
“This stands out against the teeth of more advanced odontocetes whose teeth are simpler and tend to look…
Read the full article here