摘要
在晚新生代大型食肉目动物中,鬣狗科动物地史分布广、种类和数量多,在中国出现于中中新世至更新世晚期的地层中。形态功能学家将鬣狗科的60多个化石种分为似豺、似狼和似灵猫等生态类群,这些生态类群和现生仅存的3个食骨和1个食虫类群形成鲜明的对比。生态形态学是基于生物形态与生态环境的密切关系研究不同物种形态所代表的生态位的一种方法;研究者依靠化石鬣狗类与现生种类牙齿和头骨整体形态的相似度进行了生态形态(ecomorphology)的分类,但尚未对这些已定的生态形态进行过多变量的头骨形状分析。本文拟采用平面几何形态测量学的方法对晚中新世临夏盆地的鬣狗类进行研究,并探讨以头骨形状划分其生态形态类型的可行性。几何形态测量法是以生物形态的轮廓作为数据的计算方法,虽然目前尚未被国内古生物研究者广泛采用,但自20世纪30年代多变量统计学的理论成熟以来,这一方法的理论基础和软件算法在国外得到迅速发展,至今已成为近代生物学(neontology)和古生物学形态研究领域的一个常用工具。三维几何形态测量分析也因为三维激光扫描仪的普及而变得更简单和直观。然而,化石标本由于埋藏和保存的关系通常会出现变形或残缺不全,使目前几何形态测量方法在古生物学的应用仍主要以平面数据分析为主。平面数据采集的第一步是从与标本某一平面相垂直的角度拍摄数码照片;虽然拍摄平面的选择通常由研究者自定,但一般会选择待研究类群形状变异最具代表性的一面(如,鱼类一般选取侧视)。第二步是形态的数字化,即使用某一种形态测量软件来标出地标点(landmarks;或称界标点、标志点、标点)。地标点的选择对于分析的结果有直接而且重要的影响,一般会选择Bookstein分类中的I型或II型作为地标点的标准。这两种地标点的�
The carnivoran family Hyaenidae has an evolutionary history stretching -20 Ma,with high generic diversity in the fossil record and a paucity of living species. Their ecological diversity peaked during the late Miocene,when multiple sympatric species made up a major component of the carnivoran guild in many fossil faunas. Here one group of late Miocene hyaenids and their sister family Percrocuti-dae,from the Linxia Basin of northwestern China,was studied using geometric morphometrics analysis of cranial shape. The morphology of Ictitherium and Hyaenictitherium was shown to be intermediate between those of living spotted hyena Crocuta and canids Canis and Lycaon . The larger Dinocrocuta and Adcrocuta overlap extensively in morphology with extant Crocuta . Juvenile Dinocrocuta and Crocuta are more similar to each other in cranial morphology than either is to adult individuals of their species. Furthermore,adult Hyaenictitherium and Ictitherium fall within the range of variation of extant juvenile Crocuta . These findings indicate that Crocuta and Dinocrocuta not only converge on robust adult cranial morphology,but may also share similar ontogenetic trajectories; the prolonged period of ontogeny in Crocuta required for developing the robust morphology may also be true for Dinocrocuta . The ictithere-like morphology of juvenile Crocuta suggests that adult cranial shape of the extant hyaenid is obtained via continued allometric growth from,and beyond,the ictithere bauplan.
出处
《古脊椎动物学报》
CSCD
北大核心
2010年第3期235-246,共12页
Vertebrata Palasiatica
基金
中国科学院知识创新工程重要方向项目(编号:KZCX2-YW-Q09)
国家自然科学基金重点项目(编号:40730210)资助
