A comparison of carbon/oxygen isotope ratios from the tooth enamel of two early proboscideans, Moeritherium and Barytherium to other animals of the same era (circa 37 mya) revealed to researchers the possibility of a ancient, semi-aquatic animal, linking the speculated split of dugong and elephant from a common ancestor. “The scientists” (as the article begins; that’s some lead) said that they have:

…substantial evidence to suggest that modern elephants do have ancient relatives which lived primarily in water. The next steps are to conduct similar analyses on other elephant ancestors to determine when the switch from water to land occurred, and to determine exactly when the now fully-aquatic sirenians split from their semi-aquatic proboscidean relatives.

What a strange ancestry…