THE STREAM TADPOLES OF RHINELLA RUMBOLLI (ANURA: BUFONIDAE)

HAAD BELÉN; VERA CANDIOTI MARÍA FLORENCIA; BALDO DIEGO

HERPETOLOGICA

HERPETOLOGISTS LEAGUE

Lugar: Lawrence; Año: 2014 vol. 70 p. 184 - 197

0018-0831

ABSTRACT: The Rhinella veraguensis group is a likely paraphyletic assamblage that joins 14 species of Andean toads. Larval stages of only three species have been described so far, and all of them have a distinct sucker in the abdominal region. Here we describe tadpoles of R. rumbolii, a medium-sized toad typical from forest streams of northwestern Argentina. Thirty larvae (Gosner stages 32?35) were processed for studies of external morphology, buccal cavity, and musculoskeletal system (coloration with methylene blue, scanning electron microscopy, and clearing and staining protocol for bone and cartilage). These larvae show a mosaic of features, some typical of the genus (emarginate oral disc, wide ventral gap, two anterior and three posterior labial tooth rows, prenarial papillae, one pair of infralabial papillae, quadrato-orbital commissure present, larval otic process absent, m. subarcualis rectus I with three slips, m. subarcualis rectus II?IV with a lateral slip invading branchial septum IV, and mm. mandibulolabialis superior, interhyoideus posterior, and diaphragmatopraecordialis absent), and some others exclusive of the R. veraguensis group (second anterior labial row ?A2? complete). Interestingly, a set of character states are exclusive of this species within the group, namely the lack of an abdominal sucker (only a depression in the gular region can be observed), 2?4 lingual papillae, and adrostral cartilages absent. Some of the said traits are also frequent in other stream tadpoles, such as the muscular tail, large oral disc with complete labial rows, and the anterior neurocranium wide and robust. Bufonid tadpoles exhibit an extraordinary variation in ecological aspects, such as microhabitat, and diversity in the family is to some extent paralleled within the genus Rhinella. Further comparative morphological and developmental studies, framed in inclusive phylogenetic hypotheses, are needed in order to explore patterns of shape variation in different clades and discuss character evolution and form-function relationships.