The Ontogenetic Osteohistology of the Eureptile Captorhinus aguti (Reptilia: Captorhinidae) and the Community Histology of the Early Permian Fissure-Fill Fauna Dolese Quarry, Richards Spur, Oklahoma

Palaeohistological research has greatly enhanced our ability to draw conclusions about the physiology and growth of extinct vertebrates. A comprehensive histological growth study has never been undertaken in an Early Permian taxon at the initial stages of terrestrial vertebrate evolution. Captorhinus aguti, a common Early Permian eureptile from the fissure-fill locality near Richards Spur, Oklahoma, is the ideal taxon for a study of this type. C. aguti femora from all growth stages were measured and sectioned to compare bone structure through ontogeny. Representatives of other major taxa from the Richards Spur locality were also sectioned to compare histology across the palaeocommunity. Long bones of all sectioned Richards Spur taxa, including all growth stages of C. aguti, display slow growing parallel-fibered lamellar bone with poor vascularization. Captorhinids were the only taxon from this locality that lacked growth lines, implying that they were employing a different growth strategy from the other taxa that were preserved at this locality.M.Sc