The karyotype of three Brazilian Terrarana frogs (Amphibia, Anura) with evidence of a new Barycholos species

Sérgio Siqueira,André Pansonato,Christine Strüssmann,Ariovaldo A Giaretta,Itamar Martins,Odair Aguiar Jr,Shirlei M Recco-Pimentel

doi:10.1590/s1415-47572009005000044

Abstract

A recent substantial rearrangement of the 882 described eleutherodactyline frog species has considerably improved the understanding of their systematics. Nevertheless, many taxonomic aspects of the South American eleutherodactyline species remain unknown and require further investigation using morphological, cytogenetic and molecular approaches. In this work, the karyotypes of the Brazilian species Ischnocnema juipoca (Atibaia and Campos do Jordão, SP), Barycholos cf. ternetzi (Uberlândia, MG, and Porto Nacional, TO), and Pristimantis crepitans (Chapada dos Guimarães and São Vicente, MT) were analyzed using Giemsa staining, Ag-NOR labeling, and C-banding techniques. All individuals had a diploid number of 22 chromosomes, but the Fundamental Numbers were different among species. The herein described low chromosome number of Pristimantis crepitans is unique within this genus, suggesting that cytogenetically this species is not closely related either to its congeneric species or to Ischnocnema. In addition, karyotype differences, mainly in the NOR position, clearly distinguished the two Barycholos populations, besides indicating the existence of a so far undescribed species in this genus. A taxonomic review could clarify the systematic position of P. crepitans and verify the hypothetic new Barycholos species.

Highlights

Specimens of Ischnocnema juipoca, Barycholos cf. ternetzi and Pristimantis crepitans were sampled under a permit (License no 206/2005 - CGFAU/LIC) issued by IBAMA (Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis – Brazilian Institute of the Environment and Natural Renewable Resources)
The diploid number of 22 chromosomes observed in I. juipoca, Barycholos cf. ternetzi and P. crepitans has been described for 28 other Terrarana frog species
The chromosome morphology and C-banding patterns found in the karyotype of the Barycholos cf. ternetzi specimens from Uberlândia were very similar to those previously described in Gurinhatã specimens (Campos et al, 2008)

Summary

Introduction

Heinicke et al (2007) proposed four major clades for this anuran group, comprising the species from (1) the Caribbean (Eleutherodactylus), (2) Middle America (Craugastor), (3) Northern South America (Pristimantis), and (4) Southeastern Brazil (Ischnocnema), all of them placed in a single family named Brachycephalidae. Based on DNA sequences from mitochondrial and nuclear genes of 344 species, Hedges et al (2008) placed the 882 described species of Brachycephalidae into a new taxon, Terrarana, and classified them into four families, four subfamilies, 24 genera and 11 subgenera. Two families, three subfamilies, six genera, and two subgenera were proposed and named as new taxa. The genera Brachycephalus and Ischnocnema remained in the Brachycephalidae family, a group restricted to the southeastern region of Brazil, as previously suggested by Heinicke et al (2007). Pristimantis and Barycholos were allocated to the family Strabomantidae, subfamilies Strabomantinae e Holoadeninae, respectively, which are new taxa proposed by Hedges et al (2008)

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