A new catfish of the genus Trichomycterus from the Rio Paraíba do Sul Basin, south-eastern Brazil, a supposedly migrating species (Siluriformes, Trichomycteridae)

By

Costa, Wilson J. E. M. (Wilson José Eduardo Moreira)
Katz, Axel

Type

Article

Date of Publication

2022

Original Publication

Zoosystematics and evolution

Volume

98

Series / Issue

Issue: 1

Pages

13--21

Subjects

Biodiversity , Brazilian atlantic forest , comparative osteology , Fish migration , Neotropical region , systematics

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia Pensoft

Identifiers

DOI: https://doi.org/10.3897/zse.98.72392

 

Abstract

A new species of the catfish genus Trichomycterus is described from the Rio Paraíba do Sul, south-eastern Brazil. This species exhibits some morphological character states that are unique amongst congeners, including a robust opercle and a long interopercle with numerous odontodes (50–60 opercular and 90–100 interopercular), a black bar on the basal portion of the caudal fin and a dark brown flank with a well delimited dorsal yellow stripe. It also exhibits some morphological traits that are uncommon amongst congeners, such as the presence of nine pectoral-fin rays. The presence of a shallow hyomandibular outgrowth and a ventrally expanded pre-opercular ventral flap suggests that this species is closely related to T. melanopygius, T. pradensis and T. tete. The new species also differs from T. melanopygius, T. pradensis and T. tete by having an emarginate caudal fin and a single median supra-orbital pore S6. Anecdotal evidence suggests that T. largoperculatus and T. pradensis have migratory habits, a condition not previously reported for eastern South American trichomycterines.