pel·y·co·saur 
(pĕlĭ-kə-sôr′)
(pĕlĭ-kə-sôr′)n.
Any of various extinct, chiefly carnivorous synapsids of the Carboniferous and Permian Periods, including the dimetrodon and other species with saillike structures along the back.
[New Latin Pelycosauria, name of the former suborder in which the various pelycosaurs were classified : Greek pelux, peluk-, bowl, cup (from the typical shape of the ischium ) + Greek sauros, lizard.]