INVESTIGADORES
BASSO Nestor Guillermo
artículos
Título:
A phylogenetic analysis of Pleurodema (Anura: Leptodactylidae: Leiuperinae) based on mitochondrial and nuclear gene sequences, with comments on the evolution of anuran foam nests
Autor/es:
FAIVOVICH, J.; FERRARO, D. P.; BASSO, N. G.; HADDAD, C. F. B.; TREFAUT RODRIGUES, M.; WHEELER, W. C.; LAVILLA, E. O.
Revista:
CLADISTICS (PRINT)
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2012 p. 460 - 482
ISSN:
0748-3007
Resumen:
Species of the genus 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. Here 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 macroglands
and egg-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, and the intervening tRNAVal; the nuclear gene sequences
include portions of rhodopsin exon 1 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. thaul clade (P. bufoninum, P. marmoratum, P. somuncurensis and P. thaul), the P. brachyops 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 egg-clutch structures. The optimization of these indicates that there are at
least two independent transformations from the plesiomorphic mode of foam nests to egg-clutch structures involving gelatinous
masses of different sorts (ovoid plates, masses, or strings). We hypothesize that these independent transformations could involve
changes at the behavioural (the loss of foam beating behaviour 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.