de Andrade D V, Abe A S
Departamento de Zoologia, Universidade Estadual Paulista, Rio Claro, SP, Brasil.
Comp Biochem Physiol A Physiol. 1997 Nov;118(3):685-9. doi: 10.1016/s0300-9629(96)00481-1.
Evaporative water loss (EWL) and oxygen uptake (Vo2) was measured in two species of tree frogs with cranial co-ossification, Aparasphenodon brunoi and Corythomantis greeningi. Both species use their head to seal the entrance of bromeliads, tree holes or rocky crevices used as shelters. EWL was significantly reduced in sheltered individuals of both species as compared with those exposed nude to desiccation. EWL per unit area through the head surface was significantly lower than the body skin for A. brunoi but not for C. greeningi, EWL per unit surface area through C. greeningi body skin was about 50% that of A. brunoi, indicating a less permeable skin in the former species. The relationship between cranial coossification and EWL is discussed. Vo2 in A. brunoi was comparable with other anurans of similar size, whereas in C. greeningi, it was lower than predicted from body mass. Moreover, Vo2 in C. greeningi showed less sensitivity to temperature increase than in A. brunoi. C. greeningi occurs in a drier environment than A. brunoi, and this appears to be reflected in their EWL and Vo2 characteristics.
对两种颅骨共骨化的树蛙——布鲁诺异角蟾（Aparasphenodon brunoi）和格林氏盔头雨蛙（Corythomantis greeningi）的蒸发失水量（EWL）和氧气摄入量（Vo2）进行了测量。这两个物种都用头部封闭用作庇护所的凤梨科植物叶腋、树洞或岩石裂缝的入口。与暴露在干燥环境中的个体相比，两种树蛙处于庇护所中的个体的蒸发失水量均显著降低。对于布鲁诺异角蟾，通过头部表面的单位面积蒸发失水量显著低于身体皮肤，但格林氏盔头雨蛙并非如此；通过格林氏盔头雨蛙身体皮肤的单位表面积蒸发失水量约为布鲁诺异角蟾的50%，这表明前者的皮肤渗透性较低。本文讨论了颅骨共骨化与蒸发失水量之间的关系。布鲁诺异角蟾的氧气摄入量与其他体型相似的无尾目动物相当，而格林氏盔头雨蛙的氧气摄入量低于根据体重预测的数值。此外，格林氏盔头雨蛙的氧气摄入量对温度升高的敏感性低于布鲁诺异角蟾。格林氏盔头雨蛙所处的环境比布鲁诺异角蟾更干燥，这似乎体现在它们的蒸发失水量和氧气摄入量特征上。
