synapsid reptile vs synapsid

synapsid reptile and synapsid both are nouns.

Word	Noun	Adjective	Verb	Adverb
synapsid reptile	Yes	No	No	No
synapsid	Yes	No	No	No

As nouns, synapsid reptile and synapsid are synonyms defined as:

synapsid reptile and synapsid: extinct reptile having a single pair of lateral temporal openings in the skull

synapsid reptile (noun)	synapsid (noun)
extinct reptile having a single pair of lateral temporal openings in the skull	extinct reptile having a single pair of lateral temporal openings in the skull