Description of a new species of the Neotropical cichlid genus Gymnogeophagus Miranda Ribeiro, 1918 (Teleostei: Cichliformes) from the Middle Paraná basin, Misiones, Argentina

Abstract

Gymnogeophagus jaryi , new species, is described from Southern tributaries of the Middle Paraná basin in Misiones. It can be distinguished from all other members of the genus, except from G . australis and G . caaguazuensis , by the presence of a hyaline to grey anterior portion of the dorsal fin. Gymnogeophagus jaryi differs from G . caaguazuensis by a longer caudal peduncle, caudal fin not lyrate, central portion of scales on dorsal portion of trunk light iridescent blue and by white spots in soft portion of dorsal fin in adult males, and from G . australis by the light iridescent blue coloration of central portion of scales on the dorsal portion of trunk and tail, and by the lack of scales on the soft portion of the dorsal fin. Additionally, it can be diagnosed by the following unique combination of characters: 10–11 dorsal-fin branched rays, 27–30 E1 scales, absence of lips thickening, and, in males, by the possession of a hump in adults, caudal fin not lyrate, presence of large white spots forming transversal stripes distally and in anterior area of the dorsal fin’s soft portion, central area of scales on the dorsal portion of the trunk light iridescent blue, lack of scales on the base of the dorsal fin’s soft portion, absence of a conspicuous and oblique dark band from the eye to the anterior border of the head, anterior portion of dorsal fin hyaline to grey, scales of the midlateral spot each bearing a semicircular light blue blotch, head hump starting at the horizontal through the eyes, concave anterior profile in lateral view, base of unpaired fins yellow, and whitish hyaline spots on caudal fin. The new species, based on mtDNA phylogeny, is the sister species of G . caaguazuensis from the Paraguay basin and is closely related to G . australis .

Species delimitation of neotropical Characins (Stevardiinae): Implications for taxonomy of complex groups

“…The generalized mixed Yule-coalescent GMYC method [42] allows to determine the point of transition from species-level to population-level combining models of stochastic lineage growth with coalescent theory [43] in a robust maximum-likelihood generating a ultrametric guide tree. We used this method as the main approach to exploratory delimitation (ED) of species boundaries based on DNA barcodes and to establish OTUs due to it is frequently used in empirical studies has been and outperform OTU-picking methods (relying on simple sequence similarity thresholds) and are more robust to cases where the barcoding gap is absent [44,45]. This method is useful when multiple individuals belong to putative species are analyzed [46].…”

Peces endémicos de sistemas fluviales de la Selva Atlántica en la Argentina: Áreas prioritarias para su conservación

“…Siguiendo aguas arriba llegamos al tramo de los largos rápidos y cascadas pequeñas y medianas que se desarrollan hasta alcanzar la cota de los colectores de la meseta superior (Secretaría de Minería de la Nación 2012; Araya et al 2013). Las particularidades geomorfológicas de los cursos fluviales de poseer cascadas y saltos (e.g., las conocidas cataratas del Iguazú) impidieron la colonización de grandes peces depredadores de los grandes ríos Paraná y Uruguay, y constituyen una de las causas del elevado grado de endemismos en su ictiofauna (Garavello et al 1997;Říčan et al 2018;Alonso et al 2019).…”

“…Además, se consultaron listas actualizadas de especies disponibles en Sudamérica (Reis et al 2003) (Mirande and Koerber 2020). Para determinar la distribución y el estatus de las especies de peces consideradas se consultó una amplia serie de trabajos publicados en las últimas dos décadas (López et al , 2008Casciotta and Almirón 2008;Araya et al , 2012Piálek et al 2011Piálek et al , 2015Piálek et al , 2019Říčan et al 2011, 2017Baumgarter et al 2012;Almirón et al 2014a,b;Azpelicueta and Koerber 2015;Casciotta et al 2015Casciotta et al , 2016Casciotta et al , 2017Liotta 2016;Aguilera et al 2017;Terán et al 2017;Alonso et al 2019;Ferrer and Malabarba 2020;Flores et al 2020;Mirande and Koerber 2020). Se seleccionaron las especies endémicas de cursos fluviales de la Selva Atlántica por su importancia reconocida en la conservación (Burlakova et al 2011).…”