Description of a new species and phylogenetic analysis of the subtribe Cynopoecilina, including continuous characters without discretization (Cyprinodontiformes: Rivulidae)

Abstract

A new species of the subtribe Cynopoecilina is described from the rio Gravataí basin, laguna dos Patos system, southern Brazil. The relationships of the new species among taxa of the subtribe Cynopoecilina is discussed based on two analyses: one using 71 discrete characters and other with the addition of six continuous characters analyzed without discretization. The addition of the continuous characters resulted in the first fully resolved phylogenies for Cynopoecilus and Leptolebias species, not obtained in the analysis including only discrete characters. The new species is assigned to Cynopoecilus as sister group to the remaining species of the genus. A new diagnosis is proposed for Cynopoecilus to accommodate the new species. The resulting phylogeny indicates that the occupation of the grasslands of the Pampa biome by the species of Cynopoecilus occurred along the evolution of the genus and that this event was significant for the diversification of the genus.