Treefrog diversity in the Neotropics: phylogenetic relationships of Scinax (Anura: Hylidae)

Abstract

Scinax is the most species-rich genus of neotropical treefrogs, with more than 115 known species distributed into two large clades: the S. ruber and S. catharinae clades. The S. catharinae clade includes 47 species placed in the S. perpusillus and S. catharinae groups, whereas the S. ruber clade is composed of 71 species, 12 of which are included in two groups of species: S. rostratus and S. uruguayus groups, remaining more than 50 unsigned group species. Although some studies have addressed phylogenetically the genus using few representatives, the phylogenetic relationships among their species remain poorly understood. In order to testing the monophyly of the genus, clades, and species groups currently known and exploring their interrelationships, we performed a phylogenetic analysis of total evidence including sequences of four mitochondrial and six nuclear genes, supplemented with sequences from GenBank and 155 phenotypic characters. It was included 110 of the 118 species currently known of Scinax and several new species. Most species are represented by several specimens, and more than 42% are represented by topotypes. As a result of this analysis, the genus Scinax is partitioned into four genera. Scinax is restricted to the former Scinax ruber group and is divided in nine species groups to facilitate its taxonomic study, only few species remain unassigned to any group. Julianus, originally composed of the S. uruguayus group species, is redefined to avoid the paraphyly of Scinax. Ololygon is recognized for most species of the former S. catharinae clade, and a new genus is described to avoid the potential paraphyly of Ololygon as was recognized recently by some authors. All species groups are discussed, diagnosed and characterized, in many cases presenting phenotypic synapomorphies. Based on the resulting phylogenetic hypothesis, the evolution of several character systems and the diversity of this group are discussed.Scinax is the most species-rich genus of neotropical treefrogs, with more than 115 known species distributed into two large clades: the S. ruber and S. catharinae clades. The S. catharinae clade includes 47 species placed in the S. perpusillus and S. catharinae groups, whereas the S. ruber clade is composed of 71 species, 12 of which are included in two groups of species: S. rostratus and S. uruguayus groups, remaining more than 50 unsigned group species. Although some studies have addressed phylogenetically the genus using few representatives, the phylogenetic relationships among their species remain poorly understood. In order to testing the monophyly of the genus, clades, and species groups currently known and exploring their interrelationships, we performed a phylogenetic analysis of total evidence including sequences of four mitochondrial and six nuclear genes, supplemented with sequences from GenBank and 155 phenotypic characters. It was included 110 of the 118 species currently known of Scinax and several new species. Most species are represented by several specimens, and more than 42% are represented by topotypes. As a result of this analysis, the genus Scinax is partitioned into four genera. Scinax is restricted to the former Scinax ruber group and is divided in nine species groups to facilitate its taxonomic study, only few species remain unassigned to any group. Julianus, originally composed of the S. uruguayus group species, is redefined to avoid the paraphyly of Scinax. Ololygon is recognized for most species of the former S. catharinae clade, and a new genus is described to avoid the potential paraphyly of Ololygon as was recognized recently by some authors. All species groups are discussed, diagnosed and characterized, in many cases presenting phenotypic synapomorphies. Based on the resulting phylogenetic hypothesis, the evolution of several character systems and the diversity of this group are discussed.