Abstract:
The neotropical auchenipterid catfish genus Tetranematichthys is reviewed. Tetra-nematichthys
was previously thought to be monotypic with its single species, T.
quadrifilis, reported to have a broad range encompassing major portions of the Amazon
basin and southern tributaries of the Rı´o Orinoco. Tetranematichthys quadrifilis was
rather found to be endemic to the Rio Guapore´ in the southwestern portions of the
Amazon basin and a new species of the genus is described from material originating in
the upper Rio Negro system in Brazil and Venezuela and the upper Rı´o Orinoco basin
in southern Venezuela. The new species is also apparently widespread within the
Amazon basin and the southern and north-central portions of the Rı´o Orinoco system.
The species of Tetranematichthys have distinctive modifications of the mandibular
barbel and associated systems, which are proposed as synapomorphic for the species of
the genus and that potentially function as a fishing lure.
