Karyotype analysis of seven species of the tribe Lophiohylini (Hylinae, Hylidae, Anura), with conventional and molecular cytogenetic techniques.

Simone Lilian Gruber,Celio Haddad,Sanae Kasahara

doi:10.3897/compcytogen.v6i4.3945

Abstract

Few species of the tribe Lophiohylini have been karyotyped so far, and earlier analyses were performed mainly with standard staining. Based on the analysis of seven species with use of routine banding and molecular cytogenetic techniques, the karyotypes were compared and the cytogenetic data were evaluated in the light of the current phylogenies. A karyotype with 2n = 24 and NOR in the chromosome 10 detected by Ag-impregnation and FISH with an rDNA probe was shared by Aparasphenodon bokermanni Miranda-Ribeiro, 1920, Itapotihyla langsdorffii (Duméril and Bibron, 1841), Trachycephalus sp., Trachycephalus mesophaeus (Hensel, 1867), and Trachycephalus typhonius (Linnaeus, 1758). Phyllodytes edelmoi Peixoto, Caramaschi et Freire, 2003 and Phyllodytes luteolus (Wied-Neuwied, 1824) had reduced the diploid number from 2n = 24 to 2n = 22 with one of the small-sized pairs clearly missing, and NOR in the large chromosome 2, but the karyotypes were distinct regarding the morphology of chromosome pairs 4 and 6. Based on the cytogenetic and phylogenetic data, it was presumed that the chromosome evolution occurred from an ancestral type with 2n = 24, in which a small chromosome had been translocated to one or more unidentified chromosomes. Whichever hypothesis is more probable, other rearrangements should have occurred later, to explain the karyotype differences between the two species of Phyllodytes Wagler, 1830. The majority of the species presented a small amount of centromeric C-banded heterochromatin and these regions were GC-rich. The FISH technique using a telomeric probe identified the chromosome ends and possibly (TTAGGG)n-like sequences in the repetitive DNA out of the telomeres in Itapotihyla langsdorffii and Phyllodytes edelmoi. The data herein obtained represent an important contribution for characterizing the karyotype variability within the tribe Lophiohylini scarcely analysed so far.

Highlights

The hylids of the subfamily Hylinae Rafinesque, 1815 are grouped into four large tribes: Cophomantini, Dendropsophini, Hylini, and Lophiohylini (Faivovich et al 2005, Wiens et al 2010)
In the 2n = 24 karyotypes the Ag-NORs were located on chromosome 10, at the terminal long arm in the case of A. bokermanni, Trachycephalus sp., T. mesophaeus, and T. typhonius (Fig. 1a, c–e), or at the interstitial short arm in I. langsdorffii (Fig. 1b)
The species of the tribe Lophiohylini A. bokermanni, I. langsdorffii, Trachycephalus sp., T. mesophaeus, and T. typhonius with 2n = 24 shared indistinguishable karyotypes even though there was discrepancy in morphological classification shown in Table 2 for some chromosomes, as the chromosome 3 of the species, due to slight differences in the chromosome arm proportion

Summary

Introduction

The hylids of the subfamily Hylinae Rafinesque, 1815 are grouped into four large tribes: Cophomantini, Dendropsophini, Hylini, and Lophiohylini (Faivovich et al 2005, Wiens et al 2010). The separate genus Phytotriades Jowers, Downieb & Cohen, 2009 was erected for the species Phyllodytes auratus (Boulenger, 1917) based on analysis of mitochondrial rDNA sequences. About 70 species are recognised in the tribe Lophiohylini (Frost 2011), but only a dozen of them from seven genera have been karyotyped (Catroli and Kasahara 2009). The species of the Lophiohylini genera Nyctimantis Boulenger, 1882, Tepuihyla Ayarzagüena, Señaris and Gorzula, 1993, Phyllodytes Wagler, 1830, and Phytotriades Jowers, Downieb et Cohen, 2008 have never been karyotyped

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