Saturday, August 22, 2015

[Herpetology • 2015] Phylogenetic Systematics of Egg-brooding Frogs (Anura: Hemiphractidae) and the Evolution of Direct Development


FIGURE 1. Representatives of the supraspecific taxa of Hemiphractidae recognized in this study.
 (a) A female of Cryptobatrachus remotus from Venezuela carrying on its back its recently hatched froglets, embryos undergo direct development (photo by FJMR-R); (b) A gravid female of Flectonotus pygmaeus from Venezuela carrying its eggs on a pouch on its back formed by two longitudinal flaps of skin that are adherent middorsally, endotrophic tadpoles hatch from the eggs and complete their development in water (photo by Mauricio Rivera-Correa); (c) An adult of Fritziana goeldi from Brazil (photo by JPP); (d) An adult female of the terrestrial Hemiphractus scutatus from Colombia (photo by SC-F); (e) An adult male of Hemiphractus proboscideus from Peru (photo by Giussepe Gagliardi-Urrutia); (f) A female of Stefania ginesi from Venezuela carrying its eggs on its back, embryos undergo direct development and hatch as froglets (photo by FJMR-R); (g) A female of Gastrotheca albolineata from Brazil carrying its eggs inside an enclosed pouch with a posterior opening, embryos undergo direct development and emerge from the pouch as froglets (photo by JPP); (h) A female of Gastrotheca marsupiata from Peru (photo by JMP); (j) An adult male of Gastrotheca walkeri from Venezuela (photo by FJMR-R).
Castroviejo-Fisher, Padial, De La Riva, et al, 2015. DOI: 10.11646/zootaxa.4004.1.1

Abstract
Egg-brooding frogs (Hemiphractidae) are a group of 105 currently recognized Neotropical species, with a remarkable diversity of developmental modes, from direct development to free-living and exotrophic tadpoles. Females carry their eggs on the back and embryos have unique bell-shaped gills. We inferred the evolutionary relationships of these frogs and used the resulting phylogeny to review their taxonomy and test hypotheses on the evolution of developmental modes and bell-shaped gills. Our inferences relied on a total evidence parsimony analysis of DNA sequences of up to 20 mitochondrial and nuclear genes (analyzed under tree-alignment), and 51 phenotypic characters sampled for 83% of currently valid hemiphractid species. Our analyses rendered a well-resolved phylogeny, with both Hemiphractidae (sister of Athesphatanura) and its six recognized genera being monophyletic. We also inferred novel intergeneric relationships [((Cryptobatrachus, Flectonotus), (Stefania, (Fritziana, (Hemiphractus, Gastrotheca))))], the non-monophyly of all species groups previously proposed within Gastrotheca and Stefania, and the existence of several putative new species within Fritziana and Hemiphractus. Contrary to previous hypotheses, our results support the most recent common ancestor of hemiphractids as a direct-developer. Free-living aquatic tadpoles apparently evolved from direct-developing ancestors three to eight times. Embryos of the sister taxa Cryptobatrachus and Flectonotus share a pair of single gills derived from branchial arch I, while embryos of the clade including the other four genera have two pairs of gills derived from branchial arches I and II respectively. Furthermore, in Gastrotheca the fusion of the two pairs of gills is a putative synapomorphy. We propose a revised taxonomy concordant with our optimal topologies.

Keywords: Amphibia, Cryptobatrachus, Flectonotus, Fritziana, Gastrotheca, gills, Hemiphractus, Neotropics, parsimony, Stefania, taxonomy, total evidence, tree-alignment


 (a) A female of Cryptobatrachus remotus from Venezuela carrying on its back its recently hatched froglets, embryos undergo direct development (photo by FJMR-R); (b) A gravid female of Flectonotus pygmaeus from Venezuela carrying its eggs on a pouch on its back formed by two longitudinal flaps of skin that are adherent middorsally, endotrophic tadpoles hatch from the eggs and complete their development in water (photo by Mauricio Rivera-Correa)
Castroviejo-Fisher, Padial, De La Riva, et al, 2015. DOI: 10.11646/zootaxa.4004.1.1


Castroviejo-Fisher, Santiago, José M. Padial, Ignacio De La Riva, José P. Pombal, Jr., Hélio R. Da Silva, Fernando J. M. Rojas-Runjaic, Esteban Medina-Méndez & Darrel R. Frost. 2015. Phylogenetic Systematics of Egg-brooding Frogs (Anura: Hemiphractidae) and the Evolution of Direct Development. Zootaxa. 4004(1): 1–75. DOI: 10.11646/zootaxa.4004.1.1

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