This species was previously called Metaxytherium jordani , the name used in my book. Sea Cows Sea cows are herbivorous aquatic mammals. A fifth species, the Steller's or Great Northern Sea Cow lived in the Bering Sea until hunted to extinction in the 1700's. Our fossil sea cow is an extinct genus more closely related to the Dugong than the Manatee. It was probably a direct evolutionary ancestor of the Steller's Sea Cow.
Sea cows belong to their own separate order of mammals, the Sirenia.
Note the vestigial pelvic bones, evidence of a distant terrestrial ancestor. The bones were discovered in a Zayante sand quarry and collected under the direction of Dr. Samuel P. Welles of U.C. Berkeley in October, 1963. The animal rested on its back, with the bones laid out much as in life. The creature must have been buried soon after it died before currents and animals scattered the bones. It was a very old adult.