order Testudines vs order Chelonia

order Testudines and order Chelonia both are nouns.

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

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

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

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