Zelditch Miriam Leah, Fink William L
Museum of Paleontology, University of Michigan, Ann Arbor, Michigan 48109.
Museum of Zoology and Department of Biology, University of Michigan, Ann Arbor, Michigan 48109.
J Morphol. 1995 Mar;223(3):341-355. doi: 10.1002/jmor.1052230309.
Piranhas, like many teleosts, change their diets on both ontogenetic and phylogenetic time scales. Prior studies have suggested that pervasive morphological changes in body form on a phylogenetic time scale may be related to changes in diet, but previous reports have found little shape change in piranhas on an ontogenetic time scale. We re-examine the post-transformational allometry of body form in one piranha, Pygocentrus nattereri (Kner), using the method of thin-plate splines decomposed by their partial warps. We find substantial evidence of allometry, primarily elongation of the mid-body relative to the more anterior and posterior regions, elongation of the postorbital and nape regions relative to the more anterior head and posterior body, and deepening of the head relative to the body. In addition to these pervasive changes throughout the body, there are some that are more localized, especially elongation of the postorbital region relative to eye diameter and snout, and an even more localized elongation of the snout relative to eye diameter. Initial dietary transitions are associated with changes in head and jaw proportions, but rates of shape change decelerate through growth, so that the final transition to a diet increasingly dominated by small whole fish appears associated with change largely in overall body size. © 1995 Wiley-Liss, Inc.
食人鱼和许多硬骨鱼一样，会在个体发育和系统发育的时间尺度上改变它们的饮食。先前的研究表明，在系统发育时间尺度上身体形态的普遍变化可能与饮食变化有关，但之前的报告发现食人鱼在个体发育时间尺度上几乎没有形态变化。我们使用通过其局部弯曲分解的薄板样条方法，重新研究了一种食人鱼——纳氏臀点脂鲤（Kner）——变态后的身体形态异速生长。我们发现了大量异速生长的证据，主要是身体中部相对于更靠前和靠后的区域伸长，眶后和颈背区域相对于更靠前的头部和靠后的身体伸长，以及头部相对于身体变深。除了全身这些普遍的变化外，还有一些变化更局部，特别是眶后区域相对于眼径和吻部伸长，以及吻部相对于眼径更局部的伸长。最初的饮食转变与头部和颌骨比例的变化有关，但形态变化率在生长过程中减速，因此最终向以小型整条鱼为主的饮食转变似乎主要与整体身体大小的变化有关。© 1995威利 - 利斯公司。
