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Two new species, Hyphessobrycon frickei Guimarães, Brito, Bragança, Katz & Ottoni sp. nov. and H. geryi Guimarães, Brito, Bragança, Katz & Ottoni sp. nov., are herein described, based on seven different and independent species delimitation methods, and on molecular and morphological characters, making the hypothesis of these new species supported from an integrative taxonomy perspective. They belong to the “Rosy tetra” clade, which is mainly characterized by the presence of a dark brown or black blotch on the dorsal fin and the absence of a midlateral stripe on the body. These two new species are distinguished from the other members of this clade mainly by the arrangement, shape and color pattern of humeral and dorsal-fin spots, as well as by other characters related to scale counts and body pigmentation. The placement of the new species within the “Rosy tetra” clade was based on the combination of morphological character states mentioned above and corroborated by a molecular phylogenetic analysis using the mitochondrial gene cytochrome oxidase subunit 1. In addition, a new clade (here termed Hyphessobrycon copelandi clade) within the “Rosy tetra” clade is proposed based on molecular data, comprising H. copelandi, H. frickei sp. nov., H. geryi sp. nov. and a still undescribed species. Our results corroborate the occurrence of hidden species within the “Rosy tetra” clade, as suggested by previous studies.
During a field inventory directed at trichomycterine habitats, two new species of the genus Cambeva, C. alphabelardense sp. nov. and C. betabelardense sp. nov., were found in the Rio Chapecó drainage, an area under high environmental decline due to intensive soya monoculture. These species share a peculiar head morphology and some unique osteological features, besides having a size that is smaller than in any other congener, being herein considered to be more closely related to each other than to other taxa. They differ from each other by several characters, including head shape, fin morphology, number of jaw teeth and opercular odontodes, and mesethmoid and metapterygoid shape. Furthermore, they were found in the same area, but in distinct biotopes, with one species found buried in the remnants of tree ferns and other plants on the stream bottom, restricted to a small residual fragment of the original forest, and the other species inhabiting a stream with gravel and small stones on the bottom. Field studies indicate that these species are threatened with extinction. Robust phylogenetic studies are still necessary to test relationship hypotheses involving the new taxa here described.
Streams in the Atlantic Forest of Brazil are home to a great diversity of endemic freshwater fishes, but some fish groups are still poorly known. In the last 22 years, our field inventories have recorded some species of the mountain catfish genus Trichomycterus that are endemic to the Rio Itabapoana Basin, among which two were not still described. Herein, we provide formal descriptions for these two species. One of these species is a member of the NMM-clade of the subgenus Cryptocambeva and the other one belongs to the beta-clade of the subgenus Psammocambeva. Both species are diagnosed by an exclusive combination of character states of the external morphology and osteology. This study indicates that the number of endemic trichomycterine species in the Rio Itabapoana Basin, presently five, is larger than in any other small coastal river basin of the Atlantic Forest. A key for identification of species of Trichomycterus from this basin is provided. We discuss two factors that may be responsible for the relatively high concentration of trichomycterines in this basin: streams draining separate mountain ranges or possible past connections with two neighbouring larger basins, the Rio Doce and the Rio Paraíba do Sul basins.
