tuatara vs Sphenodon punctatum

tuatara and Sphenodon punctatum both are nouns.

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

As nouns, tuatara and Sphenodon punctatum are synonyms defined as:

tuatara and Sphenodon punctatum: only extant member of the order Rhynchocephalia of large spiny lizard-like diapsid reptiles of coastal islands off New Zealand

tuatara (noun)	Sphenodon punctatum (noun)
only extant member of the order Rhynchocephalia of large spiny lizard-like diapsid reptiles of coastal islands off New Zealand	only extant member of the order Rhynchocephalia of large spiny lizard-like diapsid reptiles of coastal islands off New Zealand