Palaeobiological implications of the osteohistology of a basal sauropodomorph dinosaur from South Africa

Abstract

ABSTRACT The anatomy and histology of several dinosaur skeletal elements recovered from the Early Jurassic Upper Elliot Formation (UEF) of South Africa are examined. Anatomical comparisons with similar dinosaurs, geological provenance, and association suggest that we are dealing with the remains of a single or multiple individuals of an undetermined basal sauropodomorph taxon. The lack of autapomorphic features on the elements hamper finer resolution of the taxonomy. Except for a rib, all other elements preserve cycles of alternating fibrolamellar bone and more slowly formed lamellar bone tissue (annuli). In many instances LAGs are associated with annuli. Except for the aforementioned rib, all other bones are from one or more sub-adults that had passed their most rapid phase of growth, but were still growing at the time of death-exemplified by the abundance of calcified cartilage in the articular ends of the bones. Variation in LAGs and annuli, vascularisation, bone wall thickness and cancellous tissue within each skeletal element, as well as between elements, is assessed. Our results show evidence for a pathology, possibly osteomyelitis in one of the ribs studied. This study provides pertinent information regarding the histovariability pertaining to basal sauropodomorph dinosaurs from the UEF of the Karoo Basin.