Desmostylus hesperus

Geologic Time: Middle Miocene (~15 million years ago)

Size (25.4 mm = 1 inch): Tusk: 220 mm (curve measure) by 45 mm base width Teeth: 30 mm by 16 mm by 16 mm high and 60 mm by 40 mm by 32 mm high (with 50 mm exposed root)

Matrix: 200 mm by 110 mm by 110 mm high

Fossil Site: Temblor Formation, Fresno County, California

Code: GAF01

Price: $1250.00

Description: This is an association of a tusk and 2 teeth of the unusual marine mammal known as Desmostylus. Desmostylus was a hippopotamus-like herbivore that has elongated jaws with forward-facing tusks and most unusual teeth. The genus derives its name from these teeth (Desmostylus means bonded pillar tooth). When they first erupted from the gums they were composed on conical columns filled with dentine. As they wore down they became a group of closely associated enamel rings. The genus had a discontinuous range along the Pacific coast of North America and Japan, and was once thought to subsist upon seaweed. It is now thought to have carried out an estuarine lifestyle, feeding on freshwater aquatic plants. The larger of the teeth may have belonged to the bearer of the tusk seen here. The tusk is quite intact, with only a repaired crack near the distal end. Note the presence of preserved enamel on the tip. The teeth and tusk are well-displayed in the substantial coquina stone matrix. It is rare to obtain any teeth at all, but to have a pair of teeth in association with a tusk is quite rare. This one comes from a 20 year old collection and is the only such specimen I have to offer.