Dibranchia vs Dibranchiata

Dibranchia and Dibranchiata both are nouns.

Word	Noun	Adjective	Verb	Adverb
Dibranchia	Yes	No	No	No
Dibranchiata	Yes	No	No	No

As nouns, Dibranchia and Dibranchiata are synonyms defined as:

Dibranchia and Dibranchiata: comprising all living cephalopods except the family Nautilidae: the orders Octopoda (octopuses) and Decapoda (squids and cuttlefish)

Other synonyms of Dibranchia include subclass Dibranchia, subclass Dibranchiata.

Dibranchia (noun)	Dibranchiata (noun)
comprising all living cephalopods except the family Nautilidae: the orders Octopoda (octopuses) and Decapoda (squids and cuttlefish)	comprising all living cephalopods except the family Nautilidae: the orders Octopoda (octopuses) and Decapoda (squids and cuttlefish)