LUCELIA GONC¸ALVES VIEIRA,1 FABIANO CAMPOS LIMA,2 S^ONIA HELENA SANTESSO TEIXEIRA MENDONC¸A,3 LORENA TANNUS MENEZES,4 LIRIA QUEIROZ LUZ HIRANO ,5* AND ANDRE LUIZ QUAGLIATTO SANTOS |
ABSTRACT This study proposes the description of the development of the postcranial axial skeleton, including vertebrae, gastralium, ribs, sternum, and interclavicle, inMelanosuchus niger. Six nests weremarked and two eggs removed fromeach nest at 24-hr intervals until hatching. For posthatching evaluation, 30 hatchlingswere kept in captivity and one exemplarwas euthanized at three-day intervals. Samples were diaphanized using potassiumhydroxide (KOH), alizarin red S, and Alcian blue.Aroutinely generally usedmethodwas applied for histological evaluation. It was difficult to define in which vertebrae the development of cartilaginous centers began, but itwas possible to observe that this condensation advanced in the craniocaudal direction. The condensation started in the vertebral arches and was visibly stronger in the cervical and dorsal regions, advancing to the lumbar, sacral and, last, to the caudal region. The atlas showed a highly different morphology compared with the other cervical vertebrae, with a short intercenter, two neural arches, and a proatlas. The ossification process began in the body of cervical vertebrae III to VIII and alizarin retention decreased in the last vertebrae, indicating a craniocaudal direction in bone development, similar to cartilage formation. In the histological sections of gastralium and interclavicles of M. niger at several development stages, it was possible to observe that these elements showed intramembranous development. Anat Rec, 00:000–000, 2017. VC 2017Wiley Periodicals, Inc. Key words: black caiman; chondrogenesis; embryology; gastralium; vertebral column |