Humeral diaphysis structure across mammals
Humeral diaphysis structure across mammals
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DOI：
10.1111/evo.14170
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发表时间：
2021-01-18
期刊：
影响因子：
3.3
通讯作者：
Amson, Eli
中科院分区：
文献类型：
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作者：
Amson, Eli
长骨包括由过渡干骺端和骨干（轴）连接的关节端（骨骺）。后者的结构通常被视为四足动物（有肢脊椎动物）的规则管状。然而，对整个骨干的骨结构的评估很少。在这里，我在系统发育的背景下评估了 164 种现存和灭绝的兽类哺乳动物（有袋动物 + 胎盘动物）的整体致密性（骨分数）的整体骨干剖面。一般来说，陆地哺乳动物已经获得了数倍于高度专业化的空中、完全水生和地下的生活方式，从而可能将特定特征与这些生活方式联系起来。我发现大多数哺乳动物沿着骨干的整体致密性持续增加。这种模式在有限数量的特殊物种中发生了变化：所有空中进化枝（滑翔机和蝙蝠）都具有相当均匀且较低的值，而鲸目动物的肱骨骨干则以稍微更紧凑的中骨干区域为标志。在地下分支中，结构改变在化石类鼹鼠（真鼹鼠）及其高度改造的肱骨中最为明显。这些结果需要对关键化石的整个骨骼元素的骨骼结构进行研究，以便重建与生活方式转变相关的进化改变模式。
Long bones comprise articular ends (epiphyses) joined by transitional metaphyses and a diaphysis (shaft). The structure of the latter is often viewed as regularly tubular across tetrapods (limbed vertebrates). However, assessments of the bone structure along the whole diaphysis are rare. Here, I assess whole-diaphysis profiles of global compactness (bone fraction) of 164 species of extant and extinct therian mammals (marsupials + placentals) in a phylogenetically informed context. Generally terrestrial, mammals have acquired multiple times the highly specialized aerial, fully aquatic, and subterranean lifestyles, allowing to potentially associate specific traits with these lifestyles. I show that there is a consistent increase in global compactness along the diaphysis in most mammals. This pattern is modified in a limited number of specialized species: all aerial clades (gliders and bats) have rather uniform and low values, while cetaceans' humeral diaphysis is marked by a slightly more compact mid-diaphyseal region. Among subterranean clades, structure alterations are most obvious in fossorial talpids (true moles) and their highly modified humerus. These results call for the investigation of bone structure in whole skeletal elements of key fossils in order to reconstruct the patterns of evolutionary modifications associated with lifestyle transitions.