Meeting Abstract

P2.150  Tuesday, Jan. 5  Vasculature and dinosaur physiology: patterns in the extant realm PORTER, W. R.**; WITMER, L. M.; Ohio University; Ohio University wp298308@ohio.edu

Some dinosaurs were among the largest animals known. Great size resulted in high heat loads that required efficient thermoregulation. In extant taxa, vascular systems play a key role in such thermal phenomena as evaporative and convective cooling and basking. Thus, we hypothesize that large-bodied dinosaurs had vascular mechanisms to deal with heat. To elucidate the thermoregulatory abilities of dinosaurs, a comparative study of the vasculature of extant taxa is necessary to show blood flow patterns, areas of thermal energy exchange, and vascular physiological devices. Blood vessels of birds (pheasant, turkey), alligators, and iguanas were injected with latex/barium solutions of differing concentrations to discriminate arteries and veins in CT scans and were studied with special attention to their relation to known sites of heat exchange (oral cavity, sinuses, orbital conjunctiva). The oral vascular plexus was extensive in the specimens examined. The anastomoses within the plexus increased rostrally along the maxillary palatal shelf and premaxilla. This pattern was present in birds, alligators, and lizards. The airway vasculature was extensive in birds and alligators, although more closely associated with the nasal conchae in birds, whereas in alligators it was more closely related to the entire length of the airway. In lizards, the airway vasculature was found within the nasal vestibule and along the length of the airway. Avian vasculature, which is known to function in thermoregulation, is similar to that found in alligators and iguanas, possibly suggesting comparable thermoregulatory abilities. The next phase of this project will characterize these physiological devices in a greater diversity of diapsids and identify the vascular osteological correlates that can be assessed in extinct taxa.