n.large primitive reptile having a tall spinal sail; of the Permian or late Paleozoic in Europe and North America
英汉双解大词典
pelycosaur/ˈpɛlɪkəʊˌsɔː/
1.
N（名词）
any extinct mammal-like reptile of the order Pelycosauria, of Upper Carboniferous to Lower Permian times, from which the therapsids are thought to have evolved 盘龙