Description of the tadpole of Alsodes neuquensis Cei, 1976 and comparison with the sibling species A. gargola Gallardo, 1970 (Amphibia, Anura, Alsodidae)

Abstract

This paper describes the external and buccal cavity morphology, chondrocranium, hyobranchial apparatus and cranial muscles of Alsodes neuquensis in comparison with the sibling species A. gargola. The tadpole of A. neuquensis presents a shorter and higher tail, and a relatively smaller oral disc than A. gargola. The external larval morphology of Alsodes may be characterised as follows: (i) tooth row formula 2(2)/3(1), (ii) single row of marginal papillae with a wide rostral gap, (iii) single row of submarginal papillae in the mental region, (iv) both supra- and infraangular submarginal papillae present. The buccal features do not show marked intrageneric differences. The anterior and/or posterior pair of infralabial papillae may be simple or forked. All known tadpoles present one prenarial papilla accompanied or not by few pustules, and the lateral ridges of floor can be three to penta-armed. The chondrocranial features shared by the species of the genus Alsodes are (i) tetrapartite cartilage suprarostralis, (ii) chondrified adrostral tissue mass, (iii) processus anterolateralis of the larval crista parotica well developed or larval processus oticus, and (iv) large processus pseudopterygoideus that may be either completely fused to the basi cranii (A. vanzolinii, A. verrucosus and some A. neuquensis) or fused only at the tip (A. barrioi, A. gargola and some A. neuquensis). Larval cranial muscles are for the first time described for the genus Alsodes. They do not show differences between both species studied herein.