Lophiobrycon weitzmani, a new genus and species of glandulocaudine fish (Characiformes: Characidae) from the rio Grande drainage, upper rio Paraná system, southeastern Brazil

Abstract

A new genus and species of glandulocaudine, Lophiobrycon weitzmani, is described based on specimens collected in headwater tributary streams of the rio Grande, upper rio Paraná system, State of Minas Gerais, southeastern Brazil. The inclusion of the new species in the phylogeny of the subfamily Glandulocaudinae proposed by Weitzman & Menezes (1998), reveals a sister group relationship between the new genus and the monophyletic group composed of Glandulocauda and Mimagoniates that currently form the tribe Glandulocaudini. The new species can be readily distinguished from all other species of the tribe by the autapomorphic presence in adult male individuals (with more than 23.9 mm standard length) of an adipose-fin whose base extends for almost the entire distance between the posterior terminus of the base of the dorsal fin and the base of the upper lobe of the caudal fin and averages approximately 25% standard length, along with the presence of globular expansions formed by the lepidotrichia and hypertrophied soft tissue in the middle portions of the first and second pectoral-fin rays. The diagnosis of the tribe Glandulocaudini is modified to accommodate the new genus.<br>Um novo gênero e espécie de glandulocaudine, Lophiobrycon weitzmani, é descrito com base em exemplares coletados em riachos de cabeceira da drenagem do rio Grande, sistema do alto rio Paraná, Estado de Minas Gerais, sudeste do Brasil. A inclusão desta nova espécie na filogenia da subfamília Glandulocaudinae, proposta por Weitzman & Menezes (1998), revela uma relação de grupos irmãos entre o novo gênero e o grupo monofilético formado por Glandulocauda e Mimagoniates, atualmente compondo a tribo Glandulocaudini. A nova espécie pode ser facilmente distinguida das demais da tribo pela posse autapomórfica, nos machos adultos (com mais de 23,9 mm de comprimento padrão), de uma nadadeira adiposa com a base estendendo-se por praticamente a totalidade da distância entre a terminação posterior da base da nadadeira dorsal e base do lobo caudal superior, equivalendo em média a aproximadamente 25% do comprimento padrão, juntamente com a presença de expansões globulares, formadas por lepidotríquios e tecido mole hipertrofiado, na porção média do primeiro e segundo raios da nadadeira peitoral. A diagnose da tribo Glandulocaudini é modificada para acomodar o novo gênero

Systematics of the neotropical fish subfamily Glandulocaudinae (Teleostei: Characiformes: Characidae)

“…Over the years various new genera were added to the subfamily until Weitzman & Fink (1985: 1-3) recognized 17 genera and over 40 species in the subfamily. described a new genus, Ptychocharax, Weitzman & Menezes (1998: 187) described another, Chrysobrycon, and Castro et al (2003) described a third new genus, Lophiobrycon. The first two were placed in the Xenurobryconini, herein included in the subfamily Stevardiinae and the third in the Glandulocaudini of Weitzman & Menezes (1998) and bringing the total number of genera to 20.…”

“…Lophiobrycon weitzmani Castro, Ribeiro, Benine & Melo (2003) was assigned by its authors as a basal species related to all others within the Glandulocaudini of the former Glandulocaudinae.…”

“…6 in Castro et al, 2003), Glandulocauda (Figs. 18 and 28), most outgroup clade A, and stevardiines the premaxillary teeth clearly form two rows close to each other, but the attachments of the teeth to the jaws are clearly separated.…”

Molecular phylogeny and biogeographic history of the Neotropical tribe Glandulocaudini (Characiformes: Characidae: Stevardiinae)

“…According to morphological studies (e.g., Castro et al, 2003;Menezes, Weitzman, 2009), Glandulocauda is closely related to Mimagoniates and the clade consisting of those taxa is sister to Lophiobrycon. However, in both previous hypotheses based on DNA sequences (i.e., Oliveira et al, 2011;Thomaz et al, 2015a), Glandulocauda appears as sister to Lophiobrycon and this clade related to Mimagoniates.…”

“…The single valid species of Lophiobrycon, L. weitzmani, is considered endemic to headwater streams in the middle rio Grande basin, a tributary to the upper rio Paraná (cf. Castro et al, 2003, Menezes et al, 2008, Menezes, Weitzman, 2009Eschmeyer et al, 2017). However, specimens belonging to L. weitzmani (LBP 11820) were recently (2011) collected in a small tributary of the upper course of the rio São Francisco basin, in São Roque de Minas, Minas Gerais State.…”