Hanken J
Science. 1985 Aug 30;229(4716):871-4. doi: 10.1126/science.4023715.
Salamanders of the genus Thorius (Plethodontidae) are among the smallest tetrapods. Hypotheses of limb skeletal evolution in these vertebrates were evaluated on the basis of estimates of natural variation, comparisons of skeletal homology, and analysis of molecular phylogeny. Nine carpal arrangements occur in Thorius, more than in all twelve related genera of typically larger salamanders; six of these arrangements are unique. They represent a trend toward a decrease in the number of separate cartilages that is independent of locomotor and ecological specialization. Miniaturization may be an important source of morphological novelty, distinct from local adaptation, in vertebrates.
索里螈属（无肺螈科）的蝾螈是最小的四足动物之一。基于对自然变异的估计、骨骼同源性比较以及分子系统发育分析，对这些脊椎动物的肢体骨骼进化假说进行了评估。索里螈出现了九种腕骨排列方式，比所有十二个通常体型更大的相关蝾螈属的排列方式都要多；其中六种排列方式是独一无二的。它们代表了一种独立于运动和生态特化的、分离软骨数量减少的趋势。在脊椎动物中，小型化可能是形态新奇性的一个重要来源，与局部适应不同。
