Saturday, January 7, 2017

[Ichthyology • 2016] Gymnogeophagus terrapurpura • A New Species of Gymnogeophagus Miranda Ribeiro (Teleostei: Cichliformes) from Uruguay

Gymnogeophagus terrapurpura 
Loureiro, Zarucki, Malabarba & González-Bergonzoni, 2016 


We describe a new species of a substrate-brooding Gymnogeophagus , based on coloration characters. The new species can be distinguished from the remaining substrate-brooding species in the genus by the unique pigmentation of the dorsal fin which consists of light blue, diagonal stripes over a red background in the spiny section and a combination of round, elliptic, and elongated bright blue spots over a red background in the soft section. It can be further distinguished from all other species of Gymnogeophagus by the following combination of characters: a discontinuous bright blue band above the upper lateral line in the humeral area, light blue roundish spots over a red to orange background on the anal fin, and conspicuous bright blue horizontal bands on body. The new species inhabits a wide range of freshwater habitats in the lower rio Uruguay basin, Rio de la Plata coastal drainages and Atlantic Ocean coastal drainages in Uruguay.

Keywords: Cichlidae; Gymnogeophagus meridionalisGymnogeophagus rhabdotus; Substrate brooding; Systematics

Fig. 2: Non-type live specimens of (A) Gymnogeophagus terrapurpura from rio Santa Lucía basin, Canelones Department, Uruguay,
(B) G. rhabdotus and (C) G. meridionalis. (B) and (C) both from rio Negro basin, Tacuarembó Department, Uruguay. 

Sexual dimorphism. There is no evident sexual dimorphism except from slight differences in size. In the breeding season males are usually larger than females (10%-50% larger).

Geographic distribution. Gymnogeophagus terrapurpura is distributed from the rio Arapey (in the middle rio Uruguay basin) to all tributaries of the lower rio Uruguay basin and in the eastern coastal drainages of the Río de la Plata estuary and Atlantic Ocean in Uruguay (Fig. 6).

Ecological notes. Gymnogeophagus terrapurpura has been found in a large variety of habitats including shallow lakes, floodplain lakes, rivers, and streams, mainly associated with cobble, sandy or muddy substrates. Gymnogeophagus terrapurpura is an omnivore, feeding on zooplankton, macroinvertebrates, and periphyton (to a lesser extent), reducing greatly its feeding activity during autumn and winter when water temperature decreases, as described in a low-impacted lowland stream in Florida Department by González-Bergonzoni et al. (2016, named therein as "Gymnogeophagus sp.") and in a eutrophic shallow lake of Montevideo by Yafe et al. (2002, named therein as G. rhabdotus). Gymnogeophagus terrapurpura has been observed to brood on the substrate and exhibits substantial parental care, including aggressive territorial behavior in both males and females during the reproductive season, from November to January.

Etymology. The specific epithet refers to the G. E. Hudson novel "La Tierra Purpúrea" (as it is known in the Spanish translation), in which the main character makes a trip through the same region where the new species occurs. A noun in apposition.

Conservation status. Gymnogeophagus terrapurpura is relatively frequent and abundant in the rio Negro, the middle and lower rio Uruguay basin, and in the oriental coastal drainages of Río de la Plata estuary and Atlantic Ocean in Uruguay. No specific threats were detected, and the species can be categorized as Least Concern (LC) according to IUCN criteria (International Union for Conservation of Nature (IUCN), 2011).

Marcelo Loureiro, Matías Zarucki, Luiz R. Malabarba and Iván González-Bergonzoni. 2016.  A New Species of Gymnogeophagus Miranda Ribeiro from Uruguay (Teleostei: Cichliformes).
Neotropical Ichthyology. 14(1); e150082.  DOI: 10.1590/1982-0224-20150082

RESUMEN: Describimos una nueva especie de Gymnogeophagus con incubación de sustrato, en base a caracteres cromáticos. La nueva especie puede ser diferenciada de las restantes especies del género por la exclusiva pigmentación de la aleta dorsal, la que consiste de bandas oblicuas de color celeste sobre fondo rojo en la porción espinosa y una combinación de manchas redondas, elípticas, o alargadas azul brillantes sobre fondo rojo en la porción blanda. Además puede ser distinguida de las otras especies de Gymnogeophagus por la siguiente combinación de caracteres: banda horizontal azul iridiscente situada por encima de la línea lateral superior discontinua en la región humeral, manchas azules brillantes redondeadas sobre fondo rojo anaranjado en la aleta anal, bandas horizontales azul brillante en el cuerpo conspicuas. La nueva especie habita una amplia gama de hábitats de agua dulce en el sector inferior de la cuenca del río Uruguay, los drenajes costeros del Río de la Plata y drenajes costeros del Océano Atlántico en Uruguay.

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