Revision of the neotropical cichlid genus Gymnogeophagus Ribeiro, 1918, with descriptions of two new species (Pisces, Perciformes)

Abstract

The Neotropical cichlid genus Gymnogeophagus Ribeiro, 1918 is revised. The folio wing species are considered valid and are redescribed: G. rhabdotus (Hensel, 1870), G. gymnogenys (Hensel, 1870), G. labiatus (Hensel, 1870), G. balzanii (Perugia, 1891) and G. australis (Eigenmann, 1907). In addition, two new species are described: G. lacustris, sp. n., from the coastal region of southern Brazil and G. meridionalis, sp. n Cope, 1894) and G. australis. The synonymy proposed by Gosse is significantly re-arranged in the present paper. That author united the four species as a monophyletic assemblage he termed the genus Gymnogeophagus. In his study, however, Gosse primarily used long preserved color-less specimens, resulting in a poor definition of species and a useless key.Kullander, 1981 studying some specimens from Rio Grande do SuI recognized a thick-lipped Gymnogeophagus species, resurrecting G. labiatus from the synonymy of G. gymnogenys.The two characters used by Gosse in redefining Gymnogeophagus are reinterpreted in light of Hennig's, 1966 principles. The spine on top of the first dorsal pterygiophore has proved to be a synapomorphy for the genus, being unique among Neotropical cichlids. The absence of supraneurals, however, although a very good key-character, must be used with caution in a phylogenetic analysis. This reduction seems likely to have occurred independently in various cichlid genera. However, within Geophagines -a probably monophyletic assemblage (Kullander, 1980~), including those genera with an epibranchial lobe: Acarichthys, Biotodoma, Geophagus, Gymnogeophagus, Papiliochromis Retroculus, Apistogramma, Apistogrammoides, Biotoecus and Taeniacara -this reduction evidently occurred only once and may be assumed to be synapomorphic for Gymnogeophagus. The material examined of each Gymnogeophagus species is listed before the description of each species and comparative material is gIven at the end of the paper. Data include museums abbreviations and catalogue number, number of specimens in parenthesis, collecting locality, date and collectors.The synonymy for each species are limited to original species descriptions. The morphometric and meristic data were taken as shown on figure 1. Proportions are expressed as ratios in table 3, with minimum and maximum values given and the mean in parenthesis. The regression data were computed through routine statistical methods and are presented in table 4.Description of color in life are based on observations of living specimens and/or color photos taken just after collection of the specimen.The osteological observations were made on cleared and alizarinstained material (Taylor, 1967 enzyme method) and the drawings sketched with a stereomicroscope and "camera lucida". At least two specimens of each Gymnogeophagus species, except G. australis, were cleared, alizarin-stained and dissected for osteological observations. Radiographs were made of G. australis paratypes. An attempt was made to use specimens of aproximately the same size. Larger specimen...

Ichthyofauna of the hydrographic basin of the Chasqueiro Stream (Mirim Lagoon system, southern Brazil): generating subsidies for conservation and management

“…The collected fish were stored in plastic bags, labeled, and fixed in 10% formalin, and were then taken to the laboratory where they were transferred to 70% alcohol. Specimens were identified with the help of specialized literature (Reis & Malabarba 1988, Buckup & Reis 1997, Rodriguez & Reis 2008, Caravalho & Reis 2009, Bertaco & Lucena 2010, Carvalho et al 2012, Lucena et al 2013, Malabarba et al 2013, and specialists were consulted when needed for species confirmation. The list of species was formulated according to Wiley & Johnson (2010) and Malabarba et al (2013).…”

Feeding of two Cichlidae species (Perciformes) in an hypertrophic urban lake

“…There are no known previous studies on the diet of this species. ESCALANTE (1984) mentioned a similar diet in G. australis Eigenmann, 1907, a phylogenetically related species with similar morphology (REIS & MALABARBA, 1988). The lowest feeding overlap value between size classes evidences an ontogenetic diet change.…”

Metazoan parasites of Geophagus brasiliensis (Perciformes: Cichlidae) in Patos lagoon, extreme south of Brazil

“…This species was reported in Gymnogeophagus australis (Eigenmann, 1907) in Argentina (KOHN et al, 2007). Both of these hosts belong to the same family; they share the same feeding habit and co-occur in rivers and ponds in southern Brazil (REIS & MALABARBA, 1987).…”