Description

Desmostylus hesperus
Miocene
Temblor Formation
Fresno County, California, USA

Beautiful 38mm molar on 58mm matrix

Desmostylus is a genus of marine mammal that lived during the Oligocene and Miocene epochs, approximately 9-23 million years ago. Desmostylus belongs to the extinct order Desmostylia, a group that may be related to the sirenians (manatees and dugongs) and elephants.

Desmostylus was a large animal, with a stocky body and a short tail, measuring about 9 feet long and 3 feet at the shoulder. Its limbs were short and robust, with hoof-like bones that may have been used for walking on land or foraging on the ocean floor. It likely lived in shallow waters along the coastlines of the North Pacific, feeding on seaweed and other aquatic vegetation.

Desmostylus is known from fossils found in Japan, California, and Oregon. Its name means “bonded pillar” in Greek, referring to the unique structure of its teeth with column-like cusps pressed together to form a grinding surface. A tooth tends to be a rare find at all its known localities though hundreds were collected in the Fresno County, CA deposit back in the 70’s and 80’s. The few teeth you see at shows and online now are specimens that have popped out of old collections.