Using 2D dental geometric morphometrics to identify modern Perognathus and Chaetodipus specimens (Rodentia, Heteromyidae)

The Heteromyidae (pocket mice and kangaroo rats) are a group of extant small rodents abundant in western North America, as well as in fossil assemblages over the last 20 million years. Two genera of heteromyids, Chaetodipus and Perognathus, share similar tooth morphology and teeth are the primary fossil remains. Previous genetic studies show these extant sister genera likely diverged in the middle Miocene (~16 million years ago); however, the Chaetodipus fossil record starts in the Pleistocene (~2 million years ago). In this study, we asked whether two-dimensional geometric morphometrics on complete dentition and isolated premolars can accurately identify Chaetodipus and Perognathus specimens at the genus and species level. We landmarked the occlusal surface of the upper and lower tooth rows of modern Chaetodipus (n = 83) and Perognathus specimens (n = 80), including 12 of the 26 extant species across the two genera. We ran a canonical variates analysis to investigate whether principal ...异鼠科（Heteromyidae，囊鼠与更格卢鼠）是一类现存小型啮齿类类群，广泛分布于北美西部，同时在过去2000万年的化石组合中也有大量记录。异鼠科中的糙囊鼠属（Chaetodipus）与小囊鼠属（Perognathus）二者牙齿形态相似，而牙齿是该类群最主要的化石遗存。既往遗传学研究显示，这两个现存姊妹属大概率于中新世中期（约1600万年前）发生分化；然而糙囊鼠属的化石记录仅始于更新世（约200万年前）。本研究旨在探究，针对完整齿列与孤立前臼齿开展的二维几何形态测量学（2D geometric morphometrics）分析，能否在属与种级别准确鉴别糙囊鼠属与小囊鼠属的标本。我们对83份现代糙囊鼠属标本与80份现代小囊鼠属标本的上下齿列咬合面布设了形态标志点，涵盖两个属26个现存物种中的12个。我们通过典范变量分析（canonical variates analysis）探究主成分……