Morphological Evolution in Lepidobatrachus frogs (Anura: Ceratophryinae)

QUINZIO, SILVIA INÉS; FABREZI, MARISSA

Punta del Este

Congreso; Ninth International Congress of Vertebrate Morphology; 2010

Division of Vertebrate Morphology-Society for Integrative & Comparative Biology

The diversification of South American frogs of the Ceratophryinae clade involved terrestrial (Ceratophrys, Chacophrys) and aquatic life styles (Lepidobatrachus). Adults of ceratophryines present typical traits of terrestrial anurans (e.g. exostosed skulls, dorsal shields, keratinized spade foot) which in Lepidobatrachus are integrated with features related to aquatic life style (e.g. hyoglossal apparatus anatomy, lateral line system, complete webbed feet). Herein, descriptions of the ontogeny of two features related to aquatic (lateral line) and terrestrial (dorsal shields) life styles in Ceratophryinae are provided and compared with those of other anurans. The larval lateral line system in Lepidobatrachus differs from other anurans by the size of neuromasts, the presence of neuromasts along the upper lip, and the orientation of the oral line. The loss of this system is delayed after metamorphosis in L .llanensis but the system is conserved and functional in adults of L. laevis. In Ceratophrys cranwelli; a complex of medial and lateral shields –differentiated at juveniles stages– covers vertebrae II–VII and their transverse processes. Differently, in L. llanensis there are two medial dorsal shields, an anterior shield and a posterior one overlap on neural spines of vertebrae II–IV and V–VII respectively, these plates develop before the metamorphosis. The co-occurrence of dorsal shields with the absence of lateral line in adults of L. llanensis or the absence of dorsal shields with adults having lateral line system in L. laevis suggests the aquatic life style could be evolved in ephemeral pools of arid environments within the Lepidobatrachus genus.Ceratophrys, Chacophrys) and aquatic life styles (Lepidobatrachus). Adults of ceratophryines present typical traits of terrestrial anurans (e.g. exostosed skulls, dorsal shields, keratinized spade foot) which in Lepidobatrachus are integrated with features related to aquatic life style (e.g. hyoglossal apparatus anatomy, lateral line system, complete webbed feet). Herein, descriptions of the ontogeny of two features related to aquatic (lateral line) and terrestrial (dorsal shields) life styles in Ceratophryinae are provided and compared with those of other anurans. The larval lateral line system in Lepidobatrachus differs from other anurans by the size of neuromasts, the presence of neuromasts along the upper lip, and the orientation of the oral line. The loss of this system is delayed after metamorphosis in L .llanensis but the system is conserved and functional in adults of L. laevis. In Ceratophrys cranwelli; a complex of medial and lateral shields –differentiated at juveniles stages– covers vertebrae II–VII and their transverse processes. Differently, in L. llanensis there are two medial dorsal shields, an anterior shield and a posterior one overlap on neural spines of vertebrae II–IV and V–VII respectively, these plates develop before the metamorphosis. The co-occurrence of dorsal shields with the absence of lateral line in adults of L. llanensis or the absence of dorsal shields with adults having lateral line system in L. laevis suggests the aquatic life style could be evolved in ephemeral pools of arid environments within the Lepidobatrachus genus.