A new species of the catfish genus Trichomycterus from the La Plata River basin, southern Brazil, with comments on its putative phylogenetic position (Siluriformes: Trichomycteridae)

Abstract

The genus Trichomycterus is a highly diverse group of Neotropical catfishes that encompass almost 60% of all the cur-rently recognized species of the Trichomycteridae. A new species of this genus, T. perkos, is herein described from tribu-taries of the Paranapanema and Uruguai River basins, southern Brazil. The new species exhibits a remarkable ontogeneticchange in its pigmentation, having a unique color pattern when adult. The adult pigmentation consists of three wide darkbrown stripes, located in an inner skin layer of trunk and caudal peduncle, combined with a superficial light brown freck-led pattern on the dorsum and caudal peduncle. Small, presumably juvenile specimens lack the superficial freckles butalready have the dark stripes, thus resembling the color pattern of a few other congeners. Nevertheless, several unequiv-ocal morphological features distinguish both juveniles and adults of T. perkos from these congeners. In spite of the diffi-culties in estimating phylogenetic relationships within Trichomycterus, the new species is tentatively proposed as being the sister-taxon of a small group of species composed by T. crassicaudatus, T. igobi, and T. stawiarski.

The Jaw Adductor Muscle Complex in Teleostean Fishes: Evolution, Homologies and Revised Nomenclature (Osteichthyes: Actinopterygii)

“…, the A 2 under the alphanumeric terminology). In such morphologies some authors applied composite identifiers such as A 2 A 3 in an attempt to reflect the compound nature of the sections inserted on the lower jaw [5], [9], [11], [18], [40], [42], [69], [100], [153], [161]. Poor differentiation of the medialmost facial component of the muscle led the vast majority of authors to, however, incorrectly hypothesize that the A 3 was absent.…”

A new species of Ituglanis representing the southernmost record of the genus, with comments on phylogenetic relationships (Teleostei: Siluriformes: Trichomycteridae)

“…(a)]; (3) presence of two or fewer vertebrae between the first dorsal‐fin pterygiophore and the first anal‐fin pterygiophore (homoplastic with some glanapterygines and vandelliines). This condition is not only present in all species of Ituglanis examined, but also occurs in a number of other trichomycterines, such as Trichomycterus alterus (Marini, Nichols & La Monte 1933), Trichomycterus conradi (Eigenmann 1912), Trichomycterus caliense (Eigenmann 1912), T. mirisumba , T. perkos and Trichomycterus stellatus (Eigenmann 1918) (Morris et al ., ; Datovo et al ., ; pers. obs.…”

A new species of Cambeva (Siluriformes, Trichomycteridae) from the Rio Ivaí basin, Upper Rio Paraná basin, Paraná State, Brazil

“…balios but is distinguished by the diffuse blotches between insertion of pectorals fins, the difference in the number of teeth in ceratobranchial 5 and in the plate connected to pharyngobranchial 4 (Section 3.1.4). For specimens of C. davisi or C. iheringi (da Silva et al ., ; Nascimento et al ., ) this colour pattern is poorly misunderstood, although this two‐layer pigmentation pattern on the skin is often not known because recognition of the two layers may be difficult (Datovo et al ., ).…”