Osteology and postmetamorphic development of Telmatobius oxycephalus (Anura: Telmatobiidae) with an analysis of skeletal variation in the genus

Abstract

The osteological diversity among species of Telmatobius has been considered conservative. Nonetheless, the degree of ossification of several features varies both intraspecifically and interspecifically. Herein, intraspecific osteological variation and postmetamorphic ontogenetic changes in osteological features are described in Telmatobius oxycephalus. These data are compared with published descriptions of congeners. There is a considerable intraspecific osteological variation in T. oxycephalus, with cranial characters varying polymorphically, and the hyoid and postcranial characters being sexually dimorphic. This intraspecific variation is expressed by subtle differences in the degree of ossification or mineralization. Interspecific variation also can be described in terms of differential development of osteological features; these differences are more obvious than intraspecifically variable characters. The adult skeletons of several species of Telmatobius resemble the morphology observed in early stages of postmetamorphic development of T. oxycephalus. This is especially evident in the neopalatines, parasphenoid, sphenethmoid, exoccipitals, prootics, vomers, nasals, and plectra. These results suggest that within the conservative osteological architecture of Telmatobius, the variation observed is the result of heterochronic changes during the ossification process.

Comparative anatomy and development of pectoral and pelvic girdles in hylid anurans

“…These patterns are in accord with the many literature reports of frequent heterochronic changes in pseudids (de Sá & Lavilla, ; Fabrezi & Goldberg, ; Fabrezi, Quinzio, & Goldberg, ). A general delay in the developmental processes which also characterize other aquatic species such as Telmatobius (Barrionuevo, ) and Xenopus laevis (Porro & Richards, ), is thought to be related to spending more time in the water (Laurin, Girondot, & Loth, ).…”

A new endemic lineage of the Andean frog genusTelmatobius(Anura, Telmatobiidae) from the western slopes of the central Andes

“…Despite differences in the degree of ossification of the cranium, other differences between these species correspond to traits that show variation within a species (e.g. skin texture; see Barrionuevo & Baldo, ; Sinsch & Lehr, ; Barrionuevo, ). According to these antecedents, we suggest that T. dankoi and T. vilamensis correspond to the same species.…”

“…Although this is a plausible result, given that different characters may diverge in different moments during the process of evolutionary change (De Queiroz, ), it must be considered that the taxonomy of the genus Telmatobius is difficult. This is due mainly to the fact that the level of intraspecific variation in morphological species has not been established (Barrionuevo, ), and thus the delimitation of the species of Telmatobius based on these characters is problematic (De la Riva et al ., ). Therefore it is necessary to re‐evaluate the taxonomy of the Chilean species integrating new lines of evidence, for instance using an approximation known as integrative taxonomy (e.g.…”

Patterns of Cranial Development in Larval Rana macrocnemis: Chondrocranial Size and Shape Relationship With Pelophylax bedriagae (Anura: Ranidae)

“…Skeletal development in anuran species has been investigated in numerous studies, which are treated by Trueb and Hanken (), Wild (), Sheil (), Fabrezi and Goldberg (), Barrionuevo (). Although the literature on skeleton development of anurans is comprehensive, there have been only few studies addressing osteological descriptions of ranids (Larson, ).…”