Meeting Abstract
Cranial joints mediate feeding-generated forces while forming linkages between the different bones of the skull. The mandibular symphysis, the joint at the chin, is particularly important for understanding feeding function. Alligators and other crocodilians evolved a derived mandibular symphysis adapted to withstand significant forces during feeding behavior. These adaptations include various shapes and sizes of sutural ligaments, Meckel’s cartilage and their corresponding osteological correlates. Few studies have quantified patterns of sutural complexity in vertebrate skulls and the crocodylian symphysis provides exemplary material to test patterns of form and function. Using CT data from an ontogenetic sequence of alligators as well as other extant species of crocodylians, we measured parameters describing the complexity of the suture in order to determine patterns of scaling and disparity. The interdigitation index, number of interdigitations and surface area all scaled with isometry in alligators. Symphyses of crocodiles maintain homogenous patterns of suture shape along the length of the joint. Meckel’s cartilage is long and rodlike in longirostrine crocodilids whereas it is short and spatulate in alligatorids. These findings suggest the sutural ligament of crocodylian mandibular symphyses forms a strong linkage between mandibles. These new data enable more accurate interpretations of joint and feeding function in fossil crocodilians as well as histological studies of skeletal tissue growth and adaptive plasticity.
