Phylogenetic Systematics of the North American Fossil Caninae (Carnivora: Canidae)

作者：Richard H. Tedford, Xiaoming Wang, Beryl E. Taylor · 发表于：Bulletin of the American Museum of Natural History · 年份：2009 · DOI：10.1206/574.1 · 被引用次数：271 · 研究领域：Evolution and Paleontology Studies、Wildlife Ecology and Conservation、Animal Ecology and Behavior Studies

The canid subfamily Caninae includes all the living canids and their most recent fossil relatives. Their sister taxon is the Borophaginae with which they share an important modification of the lower carnassial, namely the presence of a bicuspid talonid, which gives this tooth an additional function in mastication. Contributing to this function is the enlargement of the posterolingual cingulum of M1 and development of a hypocone. The Caninae diverged from the Borophaginae in the narrowing and elongation of the premolars separated by diastemata and placed in a shallow ramus and narrow muzzle. These latter features allow the Caninae to be recognized in the fossil record as early as the beginning of the Oligocene (34 Ma) and constitute evidence that they represent a monophyletic group.In striking contrast to the history of the Borophaginae, the Caninae remain confined to a closely similar group of fox-sized species (Leptocyon spp.) throughout the Oligocene and showing very limited cladogenesis into the end of the medial Miocene (12 Ma), a span that saw marked adaptive divergence in the Borophaginae and the origin of all its major clades. By 12 Ma (beginning of the Clarendonian Land Mammal age) few fox-sized borophagines remained and most of those held hypocarnivorus adaptations. At that point the Vulpini appear both as mesocarnivores (Vulpes spp.) and hypocarnivores (Metalopex spp.) reproducing, on a much smaller scale, the range of adaptations shown in the initial radiation of t...