BECAS
BELLARDINI Flavio
congresos y reuniones científicas
Título:
Paleohistological features of an early Cretaceous (Albian) pterosaur ulna from Cerro de los Leones, Patagonia, Argentina
Autor/es:
BELLARDINI, FLAVIO; CODORNIÚ, LAURA
Lugar:
Corrientes
Reunión:
Jornada; XXXII jornadas argentinas de paleontología de vertebrados; 2018
Institución organizadora:
Universidad Nacional Nordeste, APA
Resumen:
The paleohistological analysis may provide helpful information about the paleobiology ofextinct vertebrates. Hence, in the last two decades several histological works hadimproved our knowledge about the biomechanical features, lifestyle strategies andontogenetic variations of pterosaurs. In order to evaluate the ontogenetic stage, weanalyze a thin-section from a pterosaur ulnar diaphysis (MCF-PVPH-881) discovered inCerro de los Leones locality (Neuquén Province), in which the continental LohanCuraFormation (Albian) outcrops. The sample is dominated by a wide and sub-circularmedullary cavity that is surrounded by a thin cortical bone ring.In the innermost cortex,secondary lamellar bone forms a distinct and avascular Inner Circumferencial Layer, inwhich the osteocyte lacunae are large and elongated. The remaining cortical region isdominated by a well-vascularized primary bone tissue in which coarsely parallel fibersshow some degree of organization. In the cortical layer there is no evidence ofannuli,lines of arrested growth or an External Fundamental System, so the periosteallayer of the MCF-PVPH-881 is entirely formed by a parallel fibered bone, such as inother pterodactyloids. The primary vascular canals are simple and differently oriented,while the bone cell lacunae are dense, rounded/oval in shape. Besides, MCF-PVPH-881cortex lacks Haversian remodeling. Both histological and morphological (i.e. well-fusedproximal epiphysis) features of the ulna suggest that the specimen was probably in anadvanced large juvenile, active-growth ontogenetic stage and that it had not acquired anasymptotic body size at the time of the death.