[Acquisition of masticatory structures in mammalian reptiles (preliminary study].
Possession of the masticatory function and apparatus appears as essential for the passage from Reptiles to Mammals. The present study, based on material of the Museum of d'Histoire Naturelle of Paris and on the literature, tries to distinguish the different stages of modification and specialization of feeding device in the cynodont theriodonts, leading to the mammalian stomatognathic system. The relationship between bone components (lateral skull and lower jaw), teeth and muscles are discussed. Induction of these changes comes from the external adductor muscular system in which the transformation from a primitive mass to mammalianlike masticatory muscles, directs this evolution. The conditions of feeding specialization of the Gomphodonts are discussed, as well as their evolutionary failure. Lastly, without taking up the quarrel about the double jaw-joint, it seems for the authors that the jaw-joint transformation appears as the most determinative element for assigning mammalian origins to the Cynodonts.
D000818:Animals; D008409:Mastication; D010161:Paleodontology; D012104:Reptiles / Q000033:anatomy & histology*
L'acquisition des structures masticatoires chez les reptiles mammaliens (étude préliminaire)