Biological Sciences Department, California State Polytechnic University, Pomona, CA, 91768, USA.
Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA, 92521, USA.
Sci Rep. 2017 Sep 20;7(1):11963. doi: 10.1038/s41598-017-11968-6.
Of the nearly 6,800 extant frog species, most have weak jaws that play only a minor role in prey capture. South American horned frogs (Ceratophrys) are a notable exception. Aggressive and able to consume vertebrates their own size, these "hopping heads" use a vice-like grip of their jaws to restrain and immobilize prey. Using a longitudinal experimental design, we quantified the ontogenetic profile of bite-force performance in post-metamorphic Ceratophrys cranwelli. Regression slopes indicate positive allometric scaling of bite force with reference to head and body size, results that concur with scaling patterns across a diversity of taxa, including fish and amniotes (lizards, tuatara, turtles, crocodylians, rodents). Our recovered scaling relationship suggests that exceptionally large individuals of a congener (C. aurita) and extinct giant frogs (Beelzebufo ampinga, Late Cretaceous of Madagascar) probably could bite with forces of 500 to 2200 N, comparable to medium to large-sized mammalian carnivores.
在现存的近 6800 种青蛙中，大多数青蛙的下颚较弱，在捕食中作用不大。而南美的角蛙（Ceratophrys）是一个显著的例外。角蛙具有攻击性，能够捕食与其自身大小相当的脊椎动物，它们利用下颚强有力的夹力来束缚和固定猎物。通过纵向实验设计，我们量化了后变态期 Ceratophrys cranwelli 的咬合力性能的个体发育特征。回归斜率表明，咬合力与头部和身体大小呈正异速生长关系，这一结果与包括鱼类和羊膜动物（蜥蜴、楔齿蜥、海龟、鳄鱼、啮齿动物）在内的多种分类群的缩放模式一致。我们的研究结果表明，同属的个体（C. aurita）和已灭绝的巨型青蛙（马达加斯加晚白垩世的 Beelzebufo ampinga）中可能存在体型异常巨大的个体，它们的咬合力可能达到 500 到 2200 牛，与中大型哺乳动物肉食动物相当。
