Description of males of Phallotorynus pankalos Lucinda, Rosa & Reis, 2005 and reappraisal of Phallotorynus species relationships (Teleostei: Cyprinodontiformes: Poeciliidae)

Abstract

Recently discovered male specimens of Phallotorynus pankalos are described and diagnosed from males of congener species on the basis of gonopodial morphology, color pattern and number of dorsal and anal-fin rays. The phylogenetic hypothesis of relationships among Phallotorynus species is reappraised with the inclusion of P. pankalos. Phallotorynus pankalos is hypothesized as sister to P. jucundus, a clade sister to P. victoriae or to a clade composed of P. dispilos and P. psittakos. Biogeography of Phallotorynus species is discussed, and it is suggested: (1) an early basal split between the rio Paraíba do Sul drainage and the Paraná-Paraguay system, separating P. fasciolatus from the ancestor of the remaining Phallotorynus species followed by a dispersal to rio Paraíba do Sul; (2) that the formation of the Sete Quedas falls may have isolated the ancestors of P. psittakos and P. dispilos. However, the sequence of events associated with the evolutionary history of Phallotorynus remains unclear and unsatisfactory.Recentemente descobertos espécimes machos de Phallotorynus pankalos são descritos e diagnosticados dos machos de espécies congêneres com base na morfologia gonopodial, padrão de colorido e número de raios das nadadeiras dorsal e anal. A hipótese de relações filogenéticas entre as espécies de Phallotorynus foi reavaliada com a inclusão de P. pankalos. Phallotorynus pankalos é hipotetizado como irmão de P. jucundus, um clado irmão de P. victoriae ou a um clado composto por P. dispilos e P. psittakos. Biogeografia das espécies de Phallotorynus é discutida, e é sugerido: (1) uma separação basal entre as drenagens do rio Paraíba do Sul e o sistema Paraná-Paraguai, separando P. fasciolatus do ancestral dos demais Phallotorynus, seguida de uma dispersão para o rio Paraíba do Sul; (2) que a formação dos saltos das Sete Quedas podem ter isolado os ancestrais de P. psittakos e P. dispilos. No entanto, a sequência de eventos associados a história evolutiva de Phallotorynus continua obscura e insatisfatória.

Peixes da planície de inundação do alto rio Paraná e áreas adjacentes: revised, annotated and updated

“…This river basin, like many others in the region, is impacted by human activities (e.g. deforestation and siltation by agricultural activities) that threaten species such as P. pankalos, which is only known from the rio Iguatemi basin, and presents small fecundity and high mortality rate of females after the first reproduction (Súarez et al, 2009;Lucinda, Graça, 2015). Moreover, these tributaries have a major importance as migratory routes and reproductive habitats for some species, such as spawning areas (Suzuki et al, 2009;Reynalte-Tataje et al, 2012); and the floodplain itself represents an important area for juveniles' growth and for the adults to feed and recover (Nakatani et al, 1997;Vazzoler et al, 1997).…”

“…Longitudinal series with 28-30 scales and transverse series with 8 scale rows. Dorsal fin with 8 rays, pectoral fin with 10 or 11, pelvic fin with 5 and anal fin with 10 (males) or 11 (females) rays (Lucinda et al, 2005;Lucinda, Graça, 2015). Ground color pale brown; scales with dark-brown border, conferring reticulate pattern to body; six to nine dark-brown rounded to irregular spots aligned on lower half of flank, alternated with dark-brown stripes.…”

First record of Phallotorynus victoriae Oliveros, 1983 (Cyprinodontiformes, Poeciliidae) for Uruguay river basin and Rio Grande do Sul, southern Brazil

“…In poecilids, the gonopodium plays a very important role in the copulation process and used as a diagnostic feature within the family (Chambers 1987, Chambers 1990, Lucinda and Graça 2015. According to Chambers (1987), the length of the gonopodium relative to the standard length varies markedly amongst the genera of Poeciliidae, forming 2 main groups: the first group formed by species with longer gonopodia (50-70% of SL).…”