Modesto Sean P, Smith Roger M H, Campione Nicolás E, Reisz Robert R
Department of Biology, Cape Breton University, Sydney, NS, Canada, B1P 6L2.
Naturwissenschaften. 2011 Dec;98(12):1027-34. doi: 10.1007/s00114-011-0856-2. Epub 2011 Oct 19.
We report on a partial varanopid skull and mandible from the Pristerognathus Assemblage Zone of the Beaufort Group, in the South African Karoo Basin, which is probably latest Middle Permian (Capitanian) in age. This mycterosaurine is not only the youngest known varanopid from the Southern Hemisphere, but it is also the youngest known "pelycosaur" (i.e., non-therapsid synapsid). Like all other members of this clade of hypercarnivores, the teeth are strongly flattened, recurved, and have finely serrated cutting edges. The anterior dentary teeth form a caniniform region, and the splenial features a foramen intermandibularis oralis, the first ever to be described in a "pelycosaur." The last varanopids were the smallest carnivores of latest Middle Permian continental faunas. Occupation of the small carnivore guild appears to have allowed varanopids to achieve a nearly cosmopolitan distribution throughout the Middle Permian, between the great Early Permian radiation of basal synapsids and the spectacular diversification of therapsid synapsids in the Late Permian and Early Triassic.
我们报告了来自南非卡鲁盆地博福特群普里斯托格纳图斯组合带的部分瓦拉诺皮德头骨和下颌骨，其年代可能为二叠纪中期最晚（卡匹敦期）。这种米克泰罗龙不仅是南半球已知最年轻的瓦拉诺皮德，也是已知最年轻的“盘龙类”（即非兽孔类合弓纲动物）。像这个超肉食性类群的所有其他成员一样，它的牙齿强烈扁平、弯曲，且有精细的锯齿状边缘。前齿骨牙齿形成一个犬齿状区域，夹板骨有一个下颌间口腔孔，这是首次在“盘龙类”中描述。最后的瓦拉诺皮德是二叠纪中期最晚大陆动物群中最小的肉食动物。占据小型肉食动物生态位似乎使瓦拉诺皮德在二叠纪中期，在基础合弓纲动物的早二叠世大辐射和二叠纪晚期及三叠纪早期兽孔类合弓纲动物的壮观多样化之间，实现了几乎遍布全球的分布。
