Biology of the sauropod dinosaurs: the evolution of gigantism.
Bottom Line: Scaling relationships between gastrointestinal tract size and basal metabolic rate (BMR) suggest that sauropods compensated for the lack of particle reduction with long retention times, even at high uptake rates.The extensive pneumatization of the axial skeleton resulted from the evolution of an avian-style respiratory system, presumably at the base of Saurischia.An avian-style respiratory system would also have lowered the cost of breathing, reduced specific gravity, and may have been important in removing excess body heat.
Affiliation: Steinmann Institute, University of Bonn, Germany. email@example.comShow MeSH
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Mentions: Dinosaurs have long been associated with extraordinary body size (Dodson, 1990), and estimates of maximal dinosaurian body size have received more than passing attention. Partially this is because of the innately human interest in identifying the largest ever representative of a group (Owen-Smith, 1988), which sometimes led to exaggerated claims of body mass for dinosaurs and fossil mammals (Fortelius & Kappelman, 1993). However, only recently has it been realized that two groups stand out among the dinosaurs from an ecological perspective, the Theropoda and the Sauropoda. While other studies (Janis & Carrano, 1992; Farlow, 1993; Paul, 1994, 1997b, 1998; Alexander, 1998) addressed this issue, that of Burness, Diamond & Flannery (2001) is most to the point. Regressing land mass size against body mass of the largest species inhabiting the land mass (top species) for recent and Pleistocene terrestrial tetrapods, Burness et al. (2001) observed that there is close correlation between these two variables when trophic level (herbivory versus carnivory) and metabolism (bradymetabolic ectothermy versus tachymetabolic endothermy) are taken into account (Fig. 3). The study included top species on land masses ranging from small oceanic islands of a few square kilometers in size to continents as large as Asia.
Affiliation: Steinmann Institute, University of Bonn, Germany. firstname.lastname@example.org