protorosaur
/ˈprəʊt(ə)rə(ʊ)sɔː/(also proterosaur) Palaeontology
noun
An early fossil reptile of the genus Protorosaurus or the order Protorosauria (now often called Araeoscelidia).
Origin
Mid 19th century; earliest use found in James Dana (1813–1895), geologist, zoologist, and teacher. From scientific Latin Protorosaurus (or Proterosaurus) Protorosaurus: see -saur.