| Astephus Temporal range: | |
|---|---|
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| Specimen of A. antiquus, National Museum of Natural History | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Siluriformes |
| Suborder: | Siluroidei |
| Family: | † Astephidae Grande & Lundberg, 1988 |
| Genus: | † Astephus Cope, 1873 |
| Type species | |
| † Pimelodus antiquus Leidy, 1873 | |
| Species | |
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Astephus is an extinct genus of freshwater catfish known from the Paleogene of western North America. It is the only member of the family Astephidae. [1] [2] [3]
Previously, it was considered potentially the oldest representative of the extant family of North American catfishes (Ictaluridae). However, more recent studies have found it to be a basal catfish that is not closely related to the Ictaluridae, and have thus placed it in its own family. [4]
There are two known species. A. antiquus(Leidy, 1873) is known from many well-preserved specimens the Early Eocene-aged Green River Formation of Colorado, Utah, and Wyoming. It is one of two catfishes known from the formation alongside Hypsidoris . They are especially common in the oil shales of the Laney Member of the formation. [5] A. resimusLundberg, 1975 is known only from a single incomplete neurocranium from the Early Eocene-aged Bridger Formation of Wyoming. [2] [6] In addition to these described species, an indeterminate Astephus species is known from the Late Paleocene-aged Polecat Bench Formation of Wyoming. [4] Indeterminate remains of Astephus, potentially representing two species, have also been identified from the Late Eocene/Early Oligocene-aged deposits from the Cypress Hills Formation of Saskatchewan. [7]