Corresponding author: Wilson J. E. M. Costa (
Academic editor: Nicolas Hubert
A new species of the catfish genus
The
Species of
This study focuses on a new species collected over 10 years ago in the main channel of the Rio Paraiba do Sul, noteworthy by exhibiting a distinctive colour pattern and some unique osteological features amongst eastern South American trichomycterines. Equally remarkable is the report of upstream migration during the collection, which is new for eastern South American trichomycterines. Due to the peculiar combination of morphological character states exhibited by the new species, making its phylogenetic positioning uncertain amongst trichomycterines, a formal description was not made before the conclusion of deeper phylogenetic studies on trichomycterines from eastern South America (
Morphometric and meristic data were taken following
UFRJ 6987, 77.8 mm
UFRJ 6988, 7, 35.2–91.5 mm
Morphometric data are in Table
Morphometric data of
Holotype | Paratypes (n = 8) | |
---|---|---|
Standard length (mm) | 77.8 | 46.6–91.5 |
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Body depth | 16.4 | 14.3–17.5 |
Caudal peduncle depth | 11.2 | 9.6–11.4 |
Body width | 9.2 | 9.6–14.7 |
Caudal peduncle width | 3.9 | 3.1–4.4 |
Pre-dorsal length | 60.4 | 58.0–62.9 |
Pre-pelvic length | 53.5 | 53.3–58.1 |
Dorsal-fin base length | 13.6 | 11.9–13.4 |
Anal-fin base length | 8.7 | 8.9–10.4 |
Caudal-fin length | 16.7 | 15.0–16.8 |
Pectoral-fin length | 15.5 | 13.8–17.0 |
Pelvic-fin length | 11.5 | 10.7–12.9 |
Head length | 21.9 | 21.9–25.1 |
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Head depth | 45.2 | 42.4–48.5 |
Head width | 81.8 | 73.9–83.6 |
Snout length | 48.4 | 42.1–45.9 |
Interorbital length | 24.3 | 21.6–28.3 |
Pre-orbital length | 15.8 | 13.2–16.4 |
Eye diameter | 11.7 | 12.2–16.1 |
Dorsal and anal fins subtriangular; total dorsal-fin rays 13 (iv + II + 7), total anal-fin rays 11 (iv + II + 5); anal-fin origin posterior to dorsal-fin base. Dorsal-fin origin at vertical through centrum of 16th or 17th vertebra; anal-fin origin at vertical between centrum of 22nd or 23rd vertebra. Pectoral fin subtriangular in dorsal view, posterior margin slightly convex, first pectoral-fin ray terminating in filament, its length about 20% of pectoral-fin length without filament; total pectoral-fin rays 9 (I + 8). Pelvic fin truncate, its posterior extremity reaching urogenital papilla; pelvic-fin bases medially separated by interspace about half-length pelvic-fin base; total pelvic-fin rays 5 (I + 4). Caudal fin emarginated, upper and lower corners rounded to slightly pointed; total principal caudal-fin rays 13 (I + 11 + I), total dorsal procurrent rays 18–22 (xvii–xxi + I), total ventral procurrent rays 14–16 (xiii–xv + I). Vertebrae 35 or 36. Ribs 11 or 12. Two dorsal hypural plates, corresponding to hypurals 4 + 5 and 3, respectively; single ventral hypural plate corresponding to hypurals 1 and 2 and parhypural.
Head of
Flank dark brown with longitudinal pale yellow stripe on dorsal portion, ventral portion yellowish white; in juveniles and most adult specimens (Fig.
Not recorded.
From the Latin, the name
Osteological structures of
Two conspicuous apomorphic conditions of the external morphology of
Map of geographical distribution of
Some morphological character states, here recorded as diagnostic for
The type series of
The only exception amongst trichomycterines from eastern South America river basins was observed during field studies on February 2014, when hundreds of specimens of
Special thanks are due to Vinicius Abilhoa for donating specimens of the new species for study. Thanks are also due to Donald Taphorn, Heok Hee Ng and Paulo Andreas Buckup for suggestions and criticisms. This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq; grant 304755/2020-6 to WJEMC) and Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ; grant E-26/202.005/2020 to AMK and E-26/201.213/2021 to WJEMC). This study was also supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Finance Code 001) through Programa de Pós-Graduação em: Biodiversidade e Biologia Evolutiva /UFRJ; Genética/UFRJ; and Zoologia, Museu Nacional/UFRJ.