Origin of the avian predentary and evidence of a unique form of cranial kinesis in Cretaceous ornithuromorphs.

ABSTRACT: The avian predentary is a small skeletal structure located rostral to the paired dentaries found only in Mesozoic ornithuromorphs. The evolution and function of this enigmatic element is unknown. Skeletal tissues forming the predentary and the lower jaws in the basal ornithuromorph Yanornis martini are identified using computed-tomography, scanning electron microscopy, and histology. On the basis of these data, we propose hypotheses for the development, structure, and function of this element. The predentary is composed of trabecular bone. The convex caudal surface articulates with rostromedial concavities on the dentaries. These articular surfaces are covered by cartilage, which on the dentaries is divided into 3 discrete patches: 1 rostral articular cartilage and 2 symphyseal cart

SUBMITTER: Bailleul AM 

PROVIDER: S-EPMC6900542 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature