MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
A phylogenetic analysis of Pleurodema (Anura: Leptodactylidae: Leiuperinae) based on mitochondrial and nuclear gene sequences, with comments on the evolution of anuran foam nests
FAIVOVICH, J.; FERRARO, D.P; BASSO, N. G.; HADDAD, C. F. B.; TREFAUT RODRIGUES, M.; WHEELER, W. C.; LAVILLA, E. O.
WILEY-BLACKWELL PUBLISHING, INC
Lugar: Londres; Año: 2012 vol. 28 p. 460 - 460
The species of Pleurodema are relatively small, plump frogs that mostly occur in strong seasonal and dry environments. The genus currently comprises 14 species distributed from Panama to southern Patagonia. In this paper we present a phylogenetic analysis of Pleurodema, including all described species and several outgroups. Our goals include testing its monophyly and the monophyly of the species groups that were historically proposed, and studying the evolution of some character systems, particularly the lumbar glands, and clutch structure; this last point also provided the chance for a discussion of foam nest evolution in anurans. Our dataset includes portions of the mitochondrial genes cytochrome b, 12S, 16S, the intervening tRNAVal. The nuclear gene sequences include portions of exon 1 of rhodopsin, and seven in absentia homolog I. Our results support a clade composed of Pleurodema and including the monotypic Somuncuria Lynch, 1978 nested within it. The latter genus is therefore considered a junior synonym of Pleurodema and its sole species is added to this genus. Furthermore, our results indicate the non-monophyly of several species groups proposed previously. We recognize four clades in Pleurodema: the P. bibroni clade (P. bibroni, P. cordobae, and P. kriegi), the P. bufoninum clade (P. bufoninum, P. marmoratum, P. somuncurensis, and P. thaul), the P. cinereum clade (P. alium, P. borellii, P. brachyops, P. cinereum, P. diplolister, and P. tucumanum), and the P. nebulosum clade (P. guayapae and P. nebulosum). Our results further indicate the need for a taxonomic reassessment of P. borellii and P. cinereum (as did previous studies), P. guayapae and P. nebulosum, and the three species in the P. bibroni clade. Pleurodema shows a striking pattern of variation in presence/absence of lumbar glands. Our results indicate multiple losses or independent gains of this character associated with defensive displays. The reproductive modes of Pleurodema include four different clutch structures. The optimization of these indicates that there are at least two independent transformations from the plesiomorphic mode of foam nests to clutch structures involving gelatinous masses of different sorts (ovoid plates, masses, or strings). We hypothesize that these independent transformations could involve changes at the behavioral (the loss of foam beating behavior by the parent) and/or structural level (transformations involving the pars convoluta dilata, the section of the oviduct where the foam making substance is secreted). Finally, our study of foam nest evolution in Pleurodema is extended to the other groups of anurans where foam nesting occurs, on the basis of available data and recent phylogenetic hypotheses. In the different hyloid groups where it occurs, foam nesting evolved from clutches laid in water. However, in all ranoids in which foam nesting occurs, it evolved from terrestrial clutches, with eggs laid hanging in vegetation, or, if the clutches are laid on a restricted volume of water, involving endotrophic development.