Development of the chondrocranium of two caiman species, Caiman latirostris and Caiman yacare.

摘要: Little is known about the embryonic development and variation of chondrocranium in Crocodylia there are no works on any Caiman species. Due to importance cranial features systematics this clade, investigating skull stages essential. In study, we present for first time cartilaginous two extant Anatomical descriptions latirostris Caiman yacare were made, paying special attention their inter- intraspecific variation. For purpose, pre-hatching ontogenetic series these caiman species prepared with a double staining diaphanization technique. The main differences other crocodylian observed palatoquadrate, interspecific within genus was recorded hyobranchial apparatus larynx. Some characters may be distinctive (posterior ventral surface otic process palatoquadrate articulated dorsal columella auris, lateral wall auditory capsule), Alligatoridae (presence an epiphanial foramen) or C. C. yacare (Corpus hyoidei different number position foramina shapes its anterior contour posterior notch, degrees broadening distal end Cornu branchiale I, presence/absence notch posteroventral cricoid). Homologies elements belonging could not confirmed. As tetrapods trachea consists incomplete rings. Morphological changes dissimilarities found study useful as context start studying phylogenetic constraints. Moreover, heterochronic context, variations involved.