Larval chondrocranium morphology of five species of Proceratophrys Miranda-Ribeiro (Amphibia; Anura; Odontophrynidae).

The chondrocranium and hyobranchial morphology are described for the tadpoles of five species of Proceratophrys Miranda-Ribeiro. The chondrocranium of P. appendiculata, P boiei, P laticeps and P. tupinamba are very similar and can be distinguished from that of P. cristiceps by: 1) less developed processus muscularis; 2) thinner palatoquadrate; 3) broadest ethmoidal region; 4) longer cornua trabeculae; and 5) morphology f the suprarostral cartilages. A morphological variation among Proceratophrys boiei is described. It reveals the existence of at least three distinct evolutionary lineages under this name. A brief comparison with other cycloramphid species is also provided.