The extensive diversity in dental form across mammals and its strong relationship with function provides insights into the diet, habitat, and behavior, of both extant and extinct taxa. Understanding the extent of variation in dental morphology across species allows for more accurate identification of fossils and a better ability to infer relationships between form and function and ecology. We examined variation in the size and shape of the first upper molar among the genus Neotoma. We employed elliptical Fourier analysis to quantify differences in the shape of 2D outlines for 23 populations and six species of Neotoma, varying in body size and habitat preference. As expected, molar length is a strong predictor of body size and is significantly and negatively correlated with temperature, particularly in species whose ranges span large latitudinal gradients. We found that differences in molar shape separate species into three general morpho-groups, with no evidence of a phylogenetic signal. While outline analysis could not robustly classify all molars to the species level, it did perform well for Neotoma cinerea, probably because of the greater degree of folding and more acute angling of molar lophs. In contrast, wider lophs with shallower enamel infolding was characteristic of species specializing on softer, more succulent resources (i.e., Neotoma albigula and Neotoma micropus). Neotoma floridana were inaccurately classified to species in the majority of cases, but were the only molars correctly identified to locality 100% of the time, suggesting that dietary specializations at a local level may drive morphological changes within the species as well as across the genus.

中文翻译：

---

新瘤内磨牙形态与生态学的关系

哺乳动物牙齿形态的广泛多样性及其与功能的密切关系为洞察已存在和已灭绝的生物群的饮食，生境和行为提供了见识。了解物种间牙齿形态变化的程度，可以更准确地鉴定化石，并具有更好的推断形式，功能与生态之间关系的能力。我们研究了Neotoma属中第一上磨牙的大小和形状的变化。我们采用椭圆傅立叶分析来量化23个种群和6种新瘤的2D轮廓形状的差异，其体型和生境偏好各异。如预期的那样，摩尔长度是体重的强烈预测指标，并且与温度呈显着负相关，特别是在范围跨越大纬度梯度的物种中。我们发现，臼齿形状的差异将物种分为三个一般的形态组，没有系统发生信号的证据。虽然轮廓分析不能有力分类全部臼齿的物种水平，但它并为表现良好Neotoma菌可能是因为折叠和摩尔lophs的更加尖锐钓鱼的程度较大。相反，具有较浅釉质折叠的较宽的狮oph是专门研究较软，多汁的资源（例如，Neotoma albigula和Neutoma micropus）的物种的特征。）。在大多数情况下，弗洛里塔娜线虫的分类不准确，但唯一能在100％的时间正确识别出臼齿的地方是臼齿，这表明在地方一级的饮食专业化可能会推动物种内以及整个属的形态变化。