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
Related in: MedlinePlus
Mentions: Large body size evolved very early on and remained a hallmark throughout sauropod evolution (Dodson, 1990). The discrepancy in body size between other dinosaurs and sauropods, as well as between the largest land mammals and sauropods (Figs 1, 2), has recently been highlighted by the availability of more accurate mass estimates (see Table 1) calculated from volume estimates based on photogrammetric measurements of actual skeletons (Gunga et al., 2007, 2008; Stoinski, Suthau & Gunga, in press) or based on scientific reconstructions (e.g. Paul, 1987, 1997a; Henderson, 1999, 2006; Seebacher, 2001). These estimates place common sauropods consistently in the 15–40 t category (Table 1). In addition, there are a number of very large sauropods, e.g. the basal macronarian Sauroposeidon (Wedel, Cifelli & Sanders, 2000a, b) and the titanosaur Argentinosaurus, for which published estimates (reviewed in Mazzetta, Christiansen & Farina, 2004) are a staggering 70–90 t! Small sauropod species with an adult body mass of less than 4–5 t are almost unknown (Table 1) with the exception of several dwarf forms from palaeo-islands (Weishampel, Grigorescu & Norman, 1991; Jianu & Weishampel, 1999; Dalla Vecchia, 2005; Sander et al., 2006; Benton et al., 2010; Stein et al., in press).
Affiliation: Steinmann Institute, University of Bonn, Germany. firstname.lastname@example.org