Different living mammals have developed a carnivorous habit (e.g., Carnivora, Dasyuridae, Thylacinidae, some Didelphidae). They exhibit different specializations for carnivory; however, they share some characters such as a carnassial molar. Previous studies have correlated the shape of molars with diet using morphometric indices or surface scans. In this work, we used 3D geometric morphometrics to explore the shape of the lower carnassials of 235 specimens corresponding to 71 extant species of Carnivora and six extant species of Marsupialia, both Didelphimorphia and Dasyuromorphia. We statistically estimated the effect of size, diet, and phylogeny on molar shape. All the analyses indicated a higher correlation between diet and molar shape, and a better correlation between molar shape and the position of each species on the phylogeny. Therefore, if we take into account the phylogenetic pattern, we can use molar morphology to infer diet of fossil species. Finally, this work evaluates for the first time, in a quantitative way, which of the lower molars of the Metatheria (m3 or m4) is the best analogue to the m1 of Carnivora; our results indicated the m4 is the best analogue.

中文翻译：

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哺乳动物食肉动物（食肉目、双翅目、蚧壳虫）的食肉进化：饮食、系统发育和异速生长

不同的现存哺乳动物已经养成了食肉习性（例如，食肉目、獾科、袋狼科、一些双翅目）。它们表现出不同的食肉专长；然而，它们有一些共同的特征，例如一颗臼齿。以前的研究使用形态测量指数或表面扫描将臼齿的形状与饮食相关联。在这项工作中，我们使用 3D 几何形态测量学来探索与 71 种现存食肉目物种和 6 种现存有袋动物物种（Didelphimorphia 和 Dasyuromorphia）相对应的 235 个标本的下部肉体的形状。我们统计地估计了大小、饮食和系统发育对磨牙形状的影响。所有的分析都表明饮食和臼齿形状之间有更高的相关性，臼齿形状和每个物种在系统发育上的位置之间有更好的相关性。所以，如果我们考虑到系统发育模式，我们可以使用摩尔形态来推断化石物种的饮食。最后，这项工作首次以定量的方式评估了 Metatheria 的下臼齿（m3 或 m4）中哪一个是与食肉目 m1 的最佳类似物；我们的结果表明 m4 是最好的模拟。