Descriptions of five new species of the Neotropical cichlid genus Gymnogeophagus Miranda Ribeiro, 1918 (Teleostei: Cichliformes) from the rio Uruguay drainage

Abstract

Gymnogeophagus is a Neotropical cichlid genus distributed in the río Paraguay, rio Paraná and rio Uruguay drainages and also in the coastal rivers of Uruguay and southern Brazil. Its monophyly is supported by two derived features: the absence of supraneurals and the presence of a forward spine in the first dorsal-fin pterygiophore. Herein, five new species of Gymnogeophagus are described from middle to upper tributaries of the rio Uruguay drainage and from the rio Negro. All these new species belong to a clade, which includes G. gymnogenys, easily recognized by sharing two synapomorphies: the absence of an oblique bar between the dorsal border of the eye and the nape, and the possession of a black bar originating in the dorsal contour near the dorsal-fin origin and directed downward and backward on the dorsum. A key to all species of Gymnogeophagus is provided.Gymnogeophagus é um gênero Neotropical de ciclídeos que ocorre nas drenagens dos rios Paraguay, Paraná e Uruguay e também em rios costeiros do Uruguay e do sul do Brasil. A monofilia do gênero é baseada em duas sinapomorfias: a ausência de supraneurais e a presença de um espinho dirigido para frente no primeiro pterigióforo da nadadeira dorsal. Neste trabalho são descritas cinco espécies novas de Gymnogeophagus de afluentes do médio ao alto rio Uruguai e rio Negro. Todas as espécies pertencem a um clado que inclui G. gymnogenys, facilmente reconhecido pelo compartilhamento de duas sinapomorfias: a ausência da barra cinza escura oblíqua entre a margem dorsal da órbita e a margem dorsal da cabeça, e a presença de uma barra cinza escura originando-se no dorso, anteriormente à nadadeira dorsal e direcionada para trás e para baixo na lateral do corpo. É fornecida uma chave de identificação para todas as espécies de Gymnogeophagus.

A new sexually dichromatic miniature Hyphessobrycon (Teleostei: Characiformes: Characidae) from the Rio Formiga, upper Rio Juruena basin, Mato Grosso, Brazil, with a review of sexual dichromatism in Characiformes

“…melanophore and carotenoid‐based pigments). Among Neotropical fishes, sexual dichromatism is commonly reported in representatives of the families Cichlidae (Lucena & Kullander, ; Kullander & Lucena, ; Kullander et al ., ; Varella & Sabaj Pérez, ; Malabarba et al ., ; Varella, ) and Cynolebiidae (Costa, , , ; Costa et al ., ). Sexually dichromatic males of these taxa develop a very bright colour pattern, often making them very popular in the aquarium trade.…”

A new mouth brooder species of Gymnogeophagus with hypertrophied lips (Cichliformes: Cichlidae)

“…Additional comparisons were done using data or specimens listed by Reis, Malabarba (1988), González-Bergonzoni et al (2009 and Loureiro et al (2016). Counts and measurements were taken according to Malabarba et al (2015) and asterisks represents counts from the holotype. Specimens listed as non-types are referred for geographical distribution record, and were not counted or measured for species description.…”

“…A brief review of the taxonomic and phylogenetic works dealing with Gymnogeophagus was given by Malabarba et al (2015) and is not repeated here. Two major clades of Gymnogeophagus are recognized: one containing substrate breeder species, whose females deposit adhesive eggs on a surface and one or both parents guard and tend them, and another that includes mouth breeder species, where one or both parents brood orally the eggs and young (Reis, Malabarba, 1988;Wimberger et al, 1998).…”

Cytogenetics of Gymnogeophagus setequedas (Cichlidae: Geophaginae), with comments on its geographical distribution

“…Within that tribe, Gymnogeophagus Miranda Ribeiro, 1918 can be diagnosed by two apomorphic traits, the absence of a supraneural bone and the presence of a forward-facing spine of the first dorsal pterygiophore (Reis, Malabarba, 1987). Gymnogeophagus currently comprises 17 species, distributed in the Paraná, Paraguay and Uruguay River basins, as well as the coastal basins of southern Brazil and Uruguay (Kullander, 2003;González-Bergonzoni et al, 2009;Malabarba et al, 2015;Loureiro et al, 2016). Gymnogeophagus setequedas is the only species of that genus considered threatened in all the Brazilian red lists.…”