Zoological Studies

Vol. 59, 2020

(update: 2020.10.13; 11.10)

Relationships and Description of a New Species of Trichomycterus (Siluriformes: Trichomycteridae) from the Rio Paraíba do Sul Basin, South-eastern Brazil

Paulo J. Vilardo1,*, Axel M. Katz1, and Wilson J. E. M. Costa1


1Laboratory of Systematics and Evolution of Teleost Fishes, Institute of Biology, Federal University of Rio de Janeiro, Caixa Postal 68049, CEP 21941-971, Rio de Janeiro, Brazil. *Correspondence: E-mail: kpaulojose@gmail.com (Vilardo)
E-mail: wcosta@acd.ufrj.br (Costa); axelmk@gmail.com (Katz)

Received 9 May 2020 / Accepted 20 August 2020
Communicated by Felipe Ottoni

A phylogenetic analysis using fragments of two nuclear and two mitochondrial genes strongly supported sister group relationships between a new species and Trichomycterus albinotatus, corroborated by unique colour patterns of adult specimens and juveniles, and morphology of the autopalatine bone. The new species is distinguished from its closest congener, T. albinotatus, by details of the colouration and number of branchiostegal rays. Both the new species and T. albinotatus are endemic to the Rio Paraíba do Sul basin, in the Atlantic Forest of south-eastern Brazil, but occur in distant and disjunct areas. The new species, herein described, is endemic to the upper section of the Rio Grande drainage, a right tributary of the lower Rio Paraíba do Sul, an area situated in the Órgãos Mountain Range. Trichomycterus albinotatus is endemic to an area about 200 km across, in the upper section of the Rio Preto that drains the Itatiaia Massif. However, both species are only known from localities above 1100 m asl, suggesting that they cannot survive in ecological conditions at lower altitudes. This study indicates that efforts are necessary to provide more accurate data on the species diversity and distribution of Trichomycterus in the biologically diverse and endangered Atlantic Forest of south-eastern Brazil.

Key words: Atlantic Forest, Biodiversity, Catfish, Molecular phylogeny, Neotropics, Systematics.

Citation: Relationships and description of a new species of Trichomycterus (Siluriformes: Trichomycteridae) from the Rio Paraíba do Sul basin, south-eastern Brazil. Zool Stud 59:53. doi:10.6620/ZS.2020.59-53.

Supplementary Materials: Table S1 | Table S2