Sunday, October 4, 2020

[Ichthyology • 2020] Ammoglanis natgeorum • A New Miniature Pencil Catfish (Siluriformes: Trichomycteridae) from the lower Atabapo River, Amazonas, Venezuela

 Ammoglanis natgeorum  
Henschel, Lujan & Baskin, 2020

A new species of the sand‐dwelling catfish genus Ammoglanis is described from a marginal habitat of the lower Atabapo River, a left‐bank blackwater tributary of the upper Orinoco River in Amazonas, Venezuela, adjacent to the border with Colombia. Ammoglanis natgeorum is distinguished from all congeners by trunk pigmentation pattern consisting of scattered ventral chromatophores concentrated around the anal‐fin base and numerous additional meristic and anatomical characteristics. A. natgeorum is the second species of Ammoglanis described from the Orinoco River basin after Ammoglanis pulex, and several shared character states (e.g., eight total dorsal‐fin rays, overall coloration pattern and presence of two finger‐like papillae posterior to chin) suggest that it is more closely related to Ammoglanis obliquus (from the central Amazon basin) and A. pulex than to other congeners.

Keywords: blackwater, Orinoco basin, psammophily, riverine infauna, Sarcoglanidinae, taxonomy

Field photos of a live  Ammoglanis natgeorum sp.n. shortly after capture

Ammoglanis natgeorum sp. nov.

Etymology: The specific epithet natgeorum honours the employees of the National Geographic Society (commonly abbreviated as NatGeo), without whose generous support this research would not have been possible. The type specimens were collected during field work funded by National Geographic CRE grant 8721‐09 to NKL, and the first author's research on Ammoglanis and other trichomycterid catfishes has been supported by a NatGeo Early Career Grant.

Elisabeth Henschel, Nathan K. Lujan and Jonathan N. Baskin. 2020. Ammoglanis natgeorum, A New Miniature Pencil Catfish (Siluriformes: Trichomycteridae) from the lower Atabapo River, Amazonas, Venezuela. Journal of Fish Biology. DOI: 10.1111/jfb.14515