Botton-Divet Léo, Cornette Raphaël, Fabre Anne-Claire, Herrel Anthony, Houssaye Alexandra
UMR 7179, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Mécadev, 57 rue Cuvier, CP 55, Paris cedex 5 75231, France
*UMR 7205, CNRS/MNHN/UPMC/EPHE, Institut de Systématique, Évolution, Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, 45 rue Buffon, Paris 75005, France.
Integr Comp Biol. 2016 Dec;56(6):1298-1309. doi: 10.1093/icb/icw124. Epub 2016 Oct 29.
The locomotor environment and behavior of quadrupedal mammals exert functional constraints on their limbs. Therefore long bone shapes are thought to reflect at least partially the species' locomotor ecology. Semi-aquatic species move through two media with distinct density and viscosity and their locomotor apparatus should therefore reflect a trade-off between the divergent functional constraints it faces. Adaptation to a semi-aquatic lifestyle occurred independently in otters (Lutrinae) and minks (Mustelinae). Analyzing semi-aquatic mustelids and their terrestrial relatives, we investigate long bone shape diversity, describe changes in long bone shape associated with a semi-aquatic lifestyle, and discuss the functional consequences of these shape changes. The robustness of the otter bones is highlighted and its potential ballast role discussed. Large epiphyses are observed in otters but this trend seems associated with terrestrial more than with aquatic locomotion. Thus, the most aquatic species, Enhydra lutris, presents narrow knee articulations compared to similar sized less aquatic species. Enhydra lutris presents a fore- and hind limb shape that diverge from that in other otters. Minks show bone shapes similar to each other but only Neovison vison tends to differ from its terrestrial relatives. The evolution of limb shape in this group is strongly correlated with size, locomotor mode, and phylogenetic history, leading to a morphological pattern where the roles of each of these factors are difficult to disentangle.
四足哺乳动物的运动环境和行为对其四肢施加功能限制。因此，长骨形状被认为至少部分反映了物种的运动生态学。半水生物种在两种具有不同密度和粘度的介质中移动，因此它们的运动器官应反映出其面临的不同功能限制之间的权衡。水獭（水獭亚科）和貂（鼬亚科）独立适应了半水生生活方式。通过分析半水生鼬科动物及其陆生亲属，我们研究了长骨形状的多样性，描述了与半水生生活方式相关的长骨形状变化，并讨论了这些形状变化的功能后果。强调了水獭骨骼的粗壮程度，并讨论了其潜在的压载作用。在水獭中观察到较大的骨骺，但这种趋势似乎与陆地运动而非水生运动有关。因此，与体型相似但水生程度较低的物种相比，最水生的物种——海獭，其膝关节连接处较窄。海獭的前肢和后肢形状与其他水獭不同。貂的骨骼形状彼此相似，但只有北美水貂往往与其陆生亲属不同。该类群肢体形状的进化与体型、运动模式和系统发育历史密切相关，导致了一种形态模式，其中这些因素各自的作用难以区分。
