Review of the species of the genus Serrapinnus Malabarba, 1998 (Teleostei: Characidae: Cheirodontinae) from the rio Tocantins-Araguaia basin, with description of three new species

Abstract

Species of the genus Serrapinnus from the rio Tocantins-Araguaia basin are revised and three new species are described. Serrapinnus aster new species is diagnosed by the presence of scimitar-shaped ventral procurrent caudal-fin rays of mature males forming a semicircle and by the presence of 7–9 cusps on the premaxillary teeth; S. lucindai new species is distinguished from its congeners by the presence of a higher number of ventral procurrent caudal-fin rays (17 to 19); and S. tocantinensis new species differs from the remaining species of the genus by the elongation of the unbranched dorsal and pelvic-fin rays into filaments in mature males. Serrapinnus sterbai is recognized as broadly distributed in the Tocantins-Araguaia basin and is redescribed based on specimens from across its entire distribution. A key for the cheirodontines occurring in the Atlantic drainages of northeastern Brazil, from the rio Tocantins-Araguaia to the rio Paraguaçú is provided.

A New Genus and Two New Species of Tetras (Characiformes: Characidae), with a Redescription and Generic Reassignment of Axelrodia lindeae Géry

“…The presence of laminar ventral procurrent caudal-fin rays was reported by Malabarba (1998) as a synapomorphy for the tribe Cheirodontini, not shared with other taxa of the family Characidae or even of the remaining representatives of the subfamily Cheirodontinae. An even more restricted feature is the ventrally arched caudal peduncle, reported as a synapomorphic character only for the genus Serrapinnus (Malabarba, 1998; Malabarba and Jerep, 2014). However, the ventral curvature of the caudal peduncle observed in Amazonichthys is distinctly less conspicuous than that reported for the genus Serrapinnus (Malabarba, 1998; Malabarba and Jerep, 2014), in which the curvature is very strong, with the posteriormost vertebrae reaching an angle of 45 degrees relative to the main longitudinal body axis.…”

Gonadal characterization of the Amazonian fish Serrapinnus kriegi (Characidae: Cheirodontinae)

“…However, to the best of our knowledge, there are no studies about its reproductive characteristics. Popularly known as "piabinha", S. kriegi species belongs to Characidae family, subfamily Cheirodontinae that includes 16 species, distributed in the main Cis-Andean basins of South America (Malabarba and Jerep, 2014;Eschmeyer et al, 2018;Jerep et al, 2018).…”

New remarkable sexually dimorphic miniature species of Hyphessobrycon (Characiformes: Characidae) from the upper Rio Tapajós basin

“…According to Rapp Py‐Daniel & Fernandes (), fishes are particularly interesting and informative organisms in studies of sexual dimorphism due to many specializations found between the sexes. Characiformes is one of the largest components of the freshwater fish fauna world‐wide, spanning numerous examples of sexual dimorphism (Weitzman & Cobb, ; Vari, ; Weitzman & Palmer, ; Zanata & Vari, ; Menezes & Weitzman, ; Gama, ; Malabarba & Jerep, ; Zanata & Camelier, ; Ota et al, ). Such cases are particularly profuse in Characidae, the most diverse family of the order (Mirande, ; Oliveira et al, ).…”