Jenynsia luxata, a new species from Northwestern Argentina, with additional observations of J. maculataRegan and phylogeny of the genus (Cyprinodontiformes: Anablepidae)

Abstract

Jenynsia luxata, a new species from northwestern Argentina, is described. This species is diagnosable from all other Jenynsia by the medial processes of left and right pelvic bones relatively reduced and separated from each other. The new species resembles J. multidentata, but it is further distinguished from this species by the absence of a swelling between the urogenital opening and the anterior base of the anal fin in females and details of coloration. Phylogenetic analyses, both under implied and equal weighting, recover the subgenera Plesiojenynsia and Jenynsia as monophyletic units. New information on previously missing characters of Jenynsia maculata is added. These data and phylogenetic characters coded for the new species herein described contribute to a better resolution of the phylogenetic relationships within the subgenus Jenynsia, which is herein supported by additional synapomorphies relative to previous phylogenies.Jenynsia luxata, una nueva especie del noroeste de Argentina, es descripta. Esta especie es diagnosticable por presentar los procesos mediales de los huesos pélvicos izquierdo y derecho relativamente reducidos y separados. La nueva especie se parece a J. multidentata, pero se distingue de ésta por la ausencia de un abultamiento entre la abertura urogenital y la base de la aleta anal en hembras y por detalles en el patrón de coloración. Los análisis filogenéticos, tanto bajo pesos implicados como iguales, recuperan los subgéneros Plesiojenynsia y Jenynsia como unidades monofiléticas. Se aporta nueva información sobre caracteres de J. maculata previamente codificados como entradas faltantes. Esos datos y los caracteres filogenéticos codificados para la nueva especie aquí descripta contribuyen a una mayor resolución de las relaciones filogenéticas dentro del subgénero Jenynsia, que está aquí soportado por sinapomorfías adicionales en relación a las filogenias previas.

Jenynsia lineata species complex, revision and new species description (Cyprinodontiformes: Anablepidae)

“…It is found in rivers and lagoons of coastal basins, inhabiting both brackish and freshwater and is distributed from the coast up to 1200 m a.s.l. in Tucumán, Argentina and from the costal habitats of the Negro River in Argentina (Aguilera et al, ) to the Araruama Lagoon in Brazil, a distance of >3600 km along the coastline.…”

“…The study will also evaluate the possibility of additional cryptic species within the J. lineata complex and generate a phylogenetic hypothesis for the complex based on the morphological matrix developed by Ghedotti (), with additional information taken from Aguilera et al . ().…”

“…With 14 species considered valid (Ghedotti & Weitzman, 1996; Aguilera et al, ), Jenynsia is the most diverse and geographically widespread genus of the neotropical family Anablepidae, inhabiting fresh, brackish and, occasionally, marine waters (Ghedotti, ; Calviño & Alonso, ). Jenynsia species are found from Atlantic coastal basins at sea level, between the Negro River, Argentina and Rio de Janeiro, Brazil, to rivers bordering the Andes at up to 2300 m a.s.l., between central Argentina and southern Bolivia (Aguilera et al, ). Despite the wide distribution of the genus, most species have a restricted distribution, being only found in several small exclusive drainages (Ghedotti & Weitzman, ; Aguilera & Mirande, ; Lucinda et al, ; Aguilera et al, ).…”

“…Jenynsia species are found from Atlantic coastal basins at sea level, between the Negro River, Argentina and Rio de Janeiro, Brazil, to rivers bordering the Andes at up to 2300 m a.s.l., between central Argentina and southern Bolivia (Aguilera et al, ). Despite the wide distribution of the genus, most species have a restricted distribution, being only found in several small exclusive drainages (Ghedotti & Weitzman, ; Aguilera & Mirande, ; Lucinda et al, ; Aguilera et al, ). An exception to this pattern is Jenynsia multidentata (Jenyns, ) , which ranges from coastal basins in Brazil, Uruguay and Argentina to areas at elevations up to 1200 m in Tucumán, Argentina (Ghedotti & Weitzman, ; Aguilera & Mirande, ).…”

“…An exception to this pattern is Jenynsia multidentata (Jenyns, ) , which ranges from coastal basins in Brazil, Uruguay and Argentina to areas at elevations up to 1200 m in Tucumán, Argentina (Ghedotti & Weitzman, ; Aguilera & Mirande, ). Such a broad geographical distribution has prompted some authors to suggest that it was caused by human introduction (Arratia et al, ; Ghedotti & Weitzman, ) or that J. multidentata is actually a species complex containing cryptic species (Ghedotti & Weitzman, ; Aguilera et al, ).…”