COMPARATIVE MORPHOLOGY AND EVOLUTION OF TADPOLES OF BOKERMANNOHYLA (ANURA: HYLIDAE: COPHOMANTINI)

We present a review of larval morphology of the Neotropical hylid frog genus Bokermannohyla. External morphology, oral cavity, and musculoskeletal systems, analyzed in 27 species of the genus and outgroups, were coded in 107 homology hypotheses, which were optimized on a comprehensive phylogenetic hypothesis of Cophomantini. Tadpoles of Bokermannohyla present a striking external and internal morphological diversity. The most important variation on the external morphology of Bokermannohyla larvae is associated with oral disc characters. Stream-related character states of Cophomantini (large oral discs; small /absence of gaps on marginal papillae; higher labial tooth row formula - LTRF), common to species of Myersiohyla and Hyloscirtus, reappear independently in species of distinct clades of Bokermannohyla, that occupy similar fast flowing rocky streams (e.g. B. pseudopseudis and B. martinsi clades). Transformation in the oral disc structures (e.g. decrease of oral disc size; larger gaps on marginal papillae; lower LTRF) appears to follow the habitat shift from rapid streams to more lentic habitats. Regarding the oral cavity, Bokermannohyla also retains many plesiomorphic character-states of the tribe, and some important transformations may have occurred in the common ancestor of the Atlantic Forest clade (e.g. diminishing of the lateral ridge papillae, and secretory pits in the glandular zone of dorsal and ventral vela). Despite overall similarity in musculoskeletal morphology among species of the genus, transformations in the shape of the articular process of palatoquadrate, trabecular horns, and anterior processes of hyobranchial may support distinct clades. The maintenance of a plesiomorphic set of robust muscles (i.e. axial muscles with attached well-developed ligaments, and the mandibular musculature), associated with modifications of the articular process of palatoquadrate, further supports the idea that the genus has retained many features of the specialized suctorial condition of the tribe.