Chelonia vs Testudines

Chelonia and Testudines both are nouns.

Word	Noun	Adjective	Verb	Adverb
Chelonia	Yes	No	No	No
Testudines	Yes	No	No	No

As nouns, Chelonia and Testudines are synonyms defined as:

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

Chelonia (noun)	Testudines (noun)
tortoises and turtles	tortoises and turtles
green turtles