OBJECT DOSSIER · SMITHSONIAN OPEN ACCESS

Desmostylian mammal — Desmostylus hesperus

SAGE Museum Deep Time scientific dossier

Artist / Creator

Marsh

Date / Period

Miocene · Miocene.

Object Type

skull cast

Medium

unknown_needs_review

About This Object

Geologic period: Miocene

Age: Miocene.

Feeding: Herbivorous or primarily plant-feeding ecology is inferred.

Evidence: Skull and tooth anatomy are direct evidence. Exact locomotor and feeding ecology remain reconstructed from skeletal form.

Why it matters: Desmostylians were an entirely extinct experiment in marine mammal evolution with no close living equivalent.

Plain Language Identity: An extinct semiaquatic desmostylian mammal from the Miocene coasts of the North Pacific.

What You Are Looking At: A cast representing the skull and unusual column-like teeth of Desmostylus hesperus.

Ecosystem: Miocene coastal and nearshore environments of the North Pacific.

Source Urls: https://naturalhistory.si.edu/visit/virtual-tour/current-exhibits/deep-time-virtual-tour-fossil-list; https://www.si.edu/object/desmostylus-hesperus-marsh-1888:nmnhpaleobiology_3391227; https://qrius.si.edu/browse/object/10022207

Find Location: Smithsonian material includes California, United States.

Enrichment Method: SAGE curated research pass; title + scientific name + source scene matched; chronology and taxonomy conflicts retained rather than silently corrected; evidence separated from inference

Scientific name: Desmostylus hesperus

Evidence / representation: comparative_taxon_visual

Why It Is In This SAGE Exhibit

comparative_taxon_visual

After the Dinosaurs: Mammals, Ice Ages and the World We Inherited.

Provenance

Smithsonian Deep Time source scene: Costs and Benefits of Living Large

Visual source institution: Wikimedia Commons

Exhibition History

Included in the SAGE Museum Dinosaurs & Deep Time staging exhibit.

Collection & Credit

Media license: Public domain

Subjects & Themes

Desmostylus hesperus Miocene skull cast Costs and Benefits of Living Large After the Dinosaurs

ORIGINAL COLLECTION SOURCE

This object page stays inside SAGE Museum. The Smithsonian link below is provided only as the original scholarly collection record. It opens separately.

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