Dissertation Research: Evolution and Functional Morphology of Incisors in Wood-cutting Castorids

论文研究：伐木蓖麻科动物门牙的进化和功能形态学

• 批准号: 0073119
• 负责人: Kathleen Smith
• 金额: $ 1万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-15 至 2002-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0073119&HistoricalAwards=false
• 关键词: Dissertation; Research; Evolution; Functional; Morphology

Rodents are more diverse and abundant than any other mammal group. Although their success has been linked to an upper and lower pair of ever-growing incisors, little is known about the evolutionary relationship between incisor shape and behavior (ex. diet) in these animals. This study will examine incisor shape in fossil and living beavers with respect to the evolution of wood-cutting. Wood-cutting is of particular interest because wood is extremely tough and it might be expected that rodents that frequently cut wood should exhibit incisors specialized for that behavior. Both living species of beaver are similar in appearance and cut wood extensively. Fossil beavers, however, are a more diverse group. For example, they ranged in size from squirrel to black-bear size. Some used their incisor for digging. They also possessed a diversity of incisor shapes. In fact, one beaver that is known to have cut wood has incisors that differ in shape from those of the living beaver. What is the behavioral and evolutionary significance of these differently shaped incisors with respect to the evolution of wood-cutting? This question will be answered by reconstructing the evolutionary relationships among beavers, studying the relationship between incisor-shape, behavior and body-size in living rodents. The PI will also examine microscopic tooth-wear features as these might help determine how rodents incisors function. This research will serve to further our understanding of the evolutionary relationship between animal form and environment. Beavers are of particular interest in this regard because they have an unusually large impact on the structure and possibly the evolution of ecosystems.

啮齿动物比任何其他哺乳动物都更多样化和丰富。 虽然它们的成功与上下一对不断生长的门牙有关，但人们对门牙形状和行为之间的进化关系知之甚少。在这些动物中。 本研究将探讨在化石和活河狸的门齿形状方面的木材切割的演变。 木材切割是特别感兴趣的，因为木材是非常坚韧的，它可能是预期的啮齿动物，经常切割木材应该表现出专门的门牙的行为。 两种现存的海狸在外观上相似，并广泛地切割木材。 然而，化石海狸是一个更加多样化的群体。 例如，它们的大小从松鼠到黑熊不等。 有些人用他们的门牙挖。 它们的门牙形状也各不相同。 事实上，有一种已知会切割木材的海狸，其门牙的形状与现存海狸的门牙不同。 这些不同形状的门齿在行为和进化上的意义是什么？ 这一问题将通过重建海狸之间的进化关系，研究现存啮齿动物的门齿形状、行为和体型之间的关系来回答。 PI还将检查微观牙齿磨损特征，因为这些可能有助于确定啮齿动物门牙的功能。 这项研究将有助于我们进一步了解动物形态与环境之间的进化关系。 海狸在这方面特别令人感兴趣，因为它们对生态系统的结构和可能的演变有着非同寻常的巨大影响。