Department of Integrative Biology, University of Texas, 2415 Speedway #C0930, Austin, TX 78712, USA.
Department of Biology University of Washington, Box 351800, Seattle, WA 98105, USA.
Syst Biol. 2022 Jun 16;71(4):788-796. doi: 10.1093/sysbio/syab091.
Although convergence is often recognized as a ubiquitous feature across the Tree of Life, whether the underlying traits also exhibit similar evolutionary pathways towards convergent forms puzzles biologists. In carnivoran mammals, "elongate," "slender," and "long" are often used to describe and even to categorize mustelids (martens, polecats, and weasels), herpestids (mongooses), viverrids (civets and genets), and other carnivorans together. But just how similar these carnivorans are and whether there is convergence in the morphological component that contribute to elongation has never been assessed. Here, I found that these qualitatively described elongate carnivorans exhibited incomplete convergence towards elongate bodies compared to other terrestrial carnivorans. In contrast, the morphological components underlying body shape variation do not exhibit convergence despite evidence that these components are more elongate in elongate carnivorans compared to nonelongate carnivorans. Furthermore, these components also exhibited shorter but different phylogenetic half-lives towards more elongate adaptive peaks, indicating that different selective pressures can create multiple pathways to elongation. Incorporating the fossil record will facilitate further investigation of whether body elongation evolved adaptively or if it is simply a retained ancestral trait.[Axial skeleton; body elongation; convergent evolution; macroevolution; phylogenetic comparative methods; thoracolumbar vertebrae.].
尽管趋同进化通常被认为是生命之树上普遍存在的特征，但基础特征是否也表现出类似的进化途径来形成趋同形态，这让生物学家感到困惑。在食肉目哺乳动物中，“长形”、“细长”和“长”等术语常被用来描述甚至分类鼬科（貂、獾和黄鼠狼）、獴科（獴）、灵猫科（灵猫和麝猫）和其他食肉动物。但是，这些食肉动物有多相似，以及在导致身体变长的形态组成部分上是否存在趋同进化，却从未被评估过。在这里，我发现与其他陆生食肉动物相比，这些定性描述的长形食肉动物在身体变长方面表现出不完全的趋同进化。相比之下，尽管有证据表明，在长形食肉动物中，这些形态组成部分比非长形食肉动物更长，但支撑身体形状变化的形态组成部分并没有表现出趋同进化。此外，这些组成部分在向更长的适应性峰演化时，也表现出较短但不同的进化半衰期，这表明不同的选择压力可以创造出多种通向变长的途径。纳入化石记录将有助于进一步研究身体变长是适应性进化的结果，还是仅仅是保留的祖先特征。[轴骨骼；身体伸长；趋同进化；宏观进化；系统发育比较方法；胸腰椎。]
