Saturday, December 29, 2012

The White-flanked Malagasy Tree Frog, A New Frog from southern Madagascar

Guibemantis tasifotsy

Mantellid frogs comprises the largest radiation of frogs in Madagascar with 200 know species in 12 genera. Within the family, at least three clades have independently adapted to phytotelmic breeding: Blommersia angolafa, Mantella laevigata, and the subgenus Pandanusicola in the genus Guibemantis. Pandanusicola are small frogs with snout–vent lengths between 20–38 mm that typically reproduce in the leaf axils of Pandanus screw pines: their eggs are deposited on leaves near the water-filled axials, and the exotrophic tadpoles develop within these leaf axial pools. This breeding mode applies to all but one species, Guibemantis liber, which deposits its eggs on leaves overhanging ponds and swamps in which its tadpoles develop. Molecular data suggests a high proportion of undescribed species diversity in Guibemantis, and two recently described  lineages were described as new species in 2011. At present, there are eight nominal species included in the subgenus Pandanusicola. The identity and delimitation of most of these species is well understood; however, G. bicalcaratus, G. liber, and G. pulcher still require revision.

One possible species characterized by a strong molecular divergence to other Pandanusicola, is morphologically intermediate between G. liber and G. pulcher. Surprisingly, this species was collected while calling on vegetation over swamps, suggesting it was not using leaf axials as a mode of reproduction as in G. liber Although the molecular data did not indicate close relationships to this species.

Evidence from morphology, bioacoustics, and mitochondrial genes suggest the species is distinctly different from G. liber as well as from G. pulcher, and consequently Lehtinen et al. (2012) describe it as new species, the White-flanked Malagasy Tree Frog, Guibemantis tasifotsy. The new frog is known only from southeastern Madagascar and differs from most Pandanusicola by probably not breeding in leaf axials of Pandanus  but instead probably lays its eggs in open lowland swamps. Newly determined DNA sequences of the cytochrome b gene confirm that G. tasifotsy is genetically highly divergent from all other species of Guibemantis.

Citation
Richard M. Lehtinen, Frank Glaw, Franco Andreone, Maciej Pabijan, and Miguel Vences. 2012. A New Species of Putatively Pond Breeding Frog of the Genus Guibemantis from Southeastern Madagascar. Copeia 2012(4):648-662.

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