RELATIONSHIPS AMONG CUTANEOUS SURFACE-AREA, CUTANEOUS MASS, AND BODY-MASS IN FROGS - A REAPPRAISAL

Physiological studies of surface-related phenomena alternatively express results on the basis of external surface area (A(s)), body mass (M(b)), or skin mass (M(skin)); seldom, however, are adequate quantitative relationships available for these variables to allow comparison of diverse studies. We compiled such relationships for the bullfrog (Rana catesbeiana), an important subject species in physiological studies, and compared our results to those of previous studies. Analysis of covariance could detect no significant variation among the allometric coefficients relating A(s) to M(b) in anuran amphibians. After adjustment for differences in M(b), by contrast, hylid and ranid frogs (including R. catesbeiana) have significantly greater A(s) than bufonids and pelobatids. The foot web contributes significantly to A(s); thus previous studies that apparently failed to include the foot web may have significantly underestimated A(s). We provide summary equations interrelating A(s), M(b), and M(skin). This study emphasizes the importance of adequate provision of morphometric data in physiological publications.