Scaling of the Indicator of Athletic Capability in Fossil and Extant Land Tetrapods

The indicator of athletic capability (Z/amgx), expressed as a function of limb bone dimensions of land tetrapods with regard to the weight they have to withstand is analysed from the point of view of its variation with regard to body mass. The results obtained using reduced major axis method suggest that this indicator varies with regard to body mass with an allometric exponent of −0.30. These results are contrasted with those obtained by several theoretical predictions. Geometric similarity, in particular, seems to explain them. However, the exponents obtained through the study of the pooled data, of different groupings, and using a least squares test tend to be lower. Since mass-specific metabolic power scale with an exponent of −0.25, it is proposed that the available power might account for this tendency.