More About Desmostylians
The desmostylians are known from about 30 million years ago until about 10 million years ago and entirely from the North Pacific Ocean. They presumably ate sea grass, which became rare with the development of kelp in the North Pacific. They did not seem to adapt to the change in diet from sea grass to kelp, as did the sea cows, the last of which were apparently killed by the Georg Wilhelm Steller expedition party in Alaska's Aleutian Islands in the 1700s.
The elephants, the sea cows, and the desmostylians are all believed to have derived from a hippopotamus-like thing called Moeritherium that lived in North Africa more than 40 million years ago. The intermediate forms are pretty well known between this ancestor and the elephants and the sea cows, but there is a gap missing between the ancestral form and the desmostylians.
Nevertheless the similarities between this ancestor and the earliest desmostylians are strong and the ancestry is believable.
In Alaska desmostylians have been found on Unalaska Island, on the Alaskan Peninsula, and on Kodiak Island. There are at least four genera included in the desmostylians. The genus Cornwallius was found on Unalaska, and the genus Desmostylia has been found on the Peninsula. The specimen found recently on Kodiak Island could be from either genus.
Dr. Charles Repenning
Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.
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