A new claroteid catfish (Siluriformes) from the upper Miocene of Toros-Menalla, Chad: Auchenoglanis soye, sp. nov.

ABSTRACT

Three specimens of a fossil catfish, collected from the Upper Miocene of Toros-Menalla (Western Djurab, Chad), are identified as members of Auchenoglanis (Claroteidae, Auchenoglanidinae) based on the shape and the ornamentation of the bones of the skull, including a markedly developed parieto-supraoccipital broadly connected with the first nuchal plate. The description is based on a comparison with living specimens of the two valid species of the genus, providing details on their bony anatomy. The fossil fish is a new species, Auchenoglanis soye sp. nov. Original features include supraoccipital process more than twice as wide as long, straight posterolateral border of the sphenotic, parurohyal with a median anterior process, and lateral articular surfaces of the second dorsal spine lateral to the foramen. Auchenoglanis fish are known since the Late Miocene and are endemic to the Nilo-Sudanese province. The fossil record was previously limited to a few isolated spines identified as Auchenoglanis sp., and A. soye sp. nov. is the first fossil species described for the genus. On the basis of preliminary observations of the ichthyofauna from Toros-Menalla, the scarcity of Auchenoglanis in the fossil record might be due to the low abundance of a fish with a rather high ecological valence.