05 August 2017
Fossil mammal make appearances here from time to time. This week is one such time when mammals will be featured exclusively. Known from sites in California, Mexico, and Florida, and described initially in 1985 by Berta and Morgan from a Floridian specimen, Enhydritherium terraenovae was a North American otter dated from approximately 9.1 to 4.9 MA. The majority of sites where this otters fossils have been recovered are in Florida, but the newest discovery was made in the Juchipila Basin of Central Mexico. This find suggests that these otters not only successfully lived on both coasts, but that they may have migrated between the coasts as well. Unlike extant otters, Enhydritherium was not yet particularly aquatic, which enabled the animal to conduct movements across expanses of dry land in ways that extant otters would find both improbable and, most likely, impossible. Not many interpretations of this large otter, an estimated 16 kg (35 lbs), exist; however, its skeleton suggests that it already had a "weasel-like" body plan and was elongated, compact, and close to the ground. It may have appeared very much like Potamotherium but was likely more stocky and larger than this more recent member of the otter family.