Sphenodon punctatum vs diapsid

Sphenodon punctatum and diapsid both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sphenodon punctatum	Yes	No	No	No
diapsid	Yes	No	No	No

As nouns, diapsid is a hypernym of Sphenodon punctatum; that is, diapsid is a word with a broader meaning than Sphenodon punctatum:

Sphenodon punctatum: only extant member of the order Rhynchocephalia of large spiny lizard-like diapsid reptiles of coastal islands off New Zealand
diapsid: reptile having a pair of openings in the skull behind each eye

Other hypernyms of Sphenodon punctatum include diapsid reptile.

Sphenodon punctatum (noun)	diapsid (noun)
only extant member of the order Rhynchocephalia of large spiny lizard-like diapsid reptiles of coastal islands off New Zealand	reptile having a pair of openings in the skull behind each eye