HR: 0800h
AN: B41D-0222    [Abstracts]
TI: Evidence for Endothermy in Pterosaurs Based on Flight Capability Analyses
AU: Jenkins, H S
EM: hillary.jenkins@duke.edu
AF: Duke University, Division of Earth & Ocean Sciences 103 Old Chemistry Box 90229, Durham, NC 27708 United States
AU: * Pratson, L F
EM: lincoln.pratson@duke.edu
AF: Duke University, Division of Earth & Ocean Sciences 103 Old Chemistry Box 90229, Durham, NC 27708 United States
AB: Previous attempts to constrain flight capability in pterosaurs have relied heavily on the fossil record, using bone articulation and apparent muscle allocation to evaluate flight potential (Frey et al., 1997; Padian, 1983; Bramwell, 1974). However, broad definitions of the physical parameters necessary for flight in pterosaurs remain loosely defined and few systematic approaches to constraining flight capability have been synthesized (Templin, 2000; Padian, 1983). Here we present a new method to assess flight capability in pterosaurs as a function of humerus length and flight velocity. By creating an energy-balance model to evaluate the power required for flight against the power available to the animal, we derive a `U'-shaped power curve and infer optimal flight speeds and maximal wingspan lengths for pterosaurs Quetzalcoatlus northropi and Pteranodon ingens. Our model corroborates empirically derived power curves for the modern black-billed magpie ( Pica Pica) and accurately reproduces the mechanical power curve for modern cockatiels ( Nymphicus hollandicus) (Tobalske et al., 2003). When we adjust our model to include an endothermic metabolic rate for pterosaurs, we find a maximal wingspan length of 18 meters for Q. northropi. Model runs using an exothermic metabolism derive maximal wingspans of 6-8 meters. As estimates based on fossil evidence show total wingspan lengths reaching up to 15 meters for Q. northropi, we conclude that large pterosaurs may have been endothermic and therefore more metabolically similar to birds than to reptiles.
DE: 0498 General or miscellaneous
SC: Biogeosciences [B]
MN: Fall Meeting 2005