The type species is Hitchcock's "A. polyzelus". Marsh's "A. major" (also known as "Ammosaurus"), "A. solus", and "A. colurus" (also known as "Yaleosaurus"), have since been recognized as synonyms of "A. polyzelus", their supposed differences being due to misinterpretation and different stages of growth. In 2015, the ICZN formally made the more complete type specimen of "A. colurus" the neotype of the genus "Anchisaurus" and the species "A. polyzelus", rendering "A. polyzelus" and "A. colurus" objective synonyms (both names being based on exactly the same fossil).