Large Desmostylus hesperus Tusk
"from the Spinner Estate Collection"

Desmostylus hesperus

Class Mammalia, Order Desmostyidia

Geological Time: Middle Miocene

Size: Fossil tusk is 36.1 cm (14 ¼”) in length on a flat lying 53.3 x 17.7 x 12.7 cm (21 x 7 x 5”) matrix base

Fossil Site: Temblor Formation, Fresno County, California

Fossil Code: PFV362

Price: $700.00 - sold

Desmostylus hesperus Tusk FossilDescription: Presented is an excellent example of a fully adult Desmostylus tusk. It exhibits excellent color and condition with a robust and impressive presence. The tip is intact. There are some naturally occurring cracks in the specimen, which are to be expected, the result of drying and contraction. It sits comfortably in a near shore matrix coquina, which is largely composed of crushed and broken fossil seashells.

This is a rare tusk of Desmostylus hesperus, an extinct placental mammal from the Middle Miocene Period some 14 - 19 million years ago. Desmostylus leaves no direct descendents, but is likely an ancient, genetic cousin to the sea cow and elephant. This specimen was collected on private land decades ago and only recently became available from an old collection. As the site is no longer collectable, Desmostylus fossils are now very hard to obtain.

Marsh first described Desmostylus in 1888 from fossils in marine deposits in Alameda County, California. Because of their limited stratigraphic range (Western North America and Japan), the unusual form of teeth that confounds determining what they ate, and their apparent combined terrestrial and marine lifestyle, they are placed in their own Order Desmostyidia within Class Mammalia.
The name Desmostylus derived from Greek means, "linked pillars". These semi-marine mammals had bodies resembling a hippopotamus, with four stout legs and four small tusks. They might have paddled around shallow water crushing shellfish for food with their heavy, columnar teeth or they may have been herbivores, or omnivores. Their closest living relatives are the Proboscidea (elephants) and Sirenia (manatees), such that they belong to the clade Afrotheria. Desmostylians grew nearly two meters in length and are thought to have weighed more than 1500 pounds.

At the end of October, 2010 I acquired a large percentage of the Paul Spinner Collection from his fossil estate manager. Paul was a Native American who worked for the U.S. Forrest Service and lived in the western side of Kern County, California. During the 1950s through the early 1980s he accumulated his collection from Fresno county, the Lompoc area fish beds, Sharktooth Hill bone beds, Kern county Brea (tar) pits, etc. As his reputation grew for having the largest privately held and valuable fossil collection from these areas, he developed a special relationship with the University of California Santa Barbara department of Paleontology as well as the La Brea Tar Pits staff. This unique collection of Southern California fossils was primarily from the Cenozoic, with an emphasis on the Miocene.

Please keep in mind that this was a unique acquisition. I have only two tusks and nine teeth specimens. Once they are gone, that is it, no more will be available.

Fossils for Sale

click fossil pictures to enlarge

Desmostylus Fossil

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