Chelonia vs order Testudinata

Chelonia and order Testudinata both are nouns.

Word	Noun	Adjective	Verb	Adverb
Chelonia	Yes	No	No	No
order Testudinata	Yes	No	No	No

As nouns, Chelonia and order Testudinata are synonyms defined as:

Other synonyms of Chelonia include order Chelonia, order Testudines, Testudinata, Testudines.

Chelonia (noun)	order Testudinata (noun)
tortoises and turtles	tortoises and turtles
green turtles