INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Paleoneurology of extinct horned turtles (Meiolaniidae) from Argentina and Australia
Autor/es:
POROPAT, S.; PAULINA CARABAJAL, A.; GEORGI, J.; STERLI, J.; KEAR, B.
Lugar:
Gral. Roca
Reunión:
Congreso; 11 Congreso de la Asociación Paleontológica Argentina; 2016
Institución organizadora:
Asociación Paleontológica Argentina-IIPG
Resumen:
Turtles are one of the least explored clades of reptiles regarding paleoneuroanatomy. Here we describe the endocranial morphology of the extinct terrestrial horned meiolaniid turtles Niolamia argentina and Gaffneylania auricularis from Patagonia, and Meiolania platyceps from Australia, along with six terrestrial testudinid species, using CT scans. The new information on the endocranial morphology of these two clades of turtles adds novel anatomical data to the poorly understood paleoneuroanatomy of the group. Comparisons showed that meiolaniids have hypertrophied nasal cavities, and in general terms exhibit more marked angles between the forebrain, midbrain and hidbrain than testudinids. The inner ear of meiolaniids did not showed marked differences with other terrestrial turtles. Calculations of olfactory ratios and comparisons of inner ear morphology were made to approach on the sensorial capacities developed by the extinct forms. Paleobiological implications of the meiolaniid hypertrophied nasal cavity were tested, although the primary functional morphology of the enlarged cavum nasi proprium remains unknown. Turtles have low hearing frequency range and the high olfactory ratios calculated here support a high reliance on olfaction for both extinct and extant turtles. Regarding this, the enlargement of the nasal cavity as for olfaction improvement was discarded, since comparisons of the volume of the nasal cavity and the olfactory ratios of meiolaniids and testudinids indicate no correlation between the size of the nasal cavity and the olfactory acuity. Other possible scenarios such as resonance chamber (vocalization) or thermoregulation (cooling of blood in its path to the brain) seem to be also unlikely.