Anas acuta vs pin-tailed duck

Anas acuta and pin-tailed duck both are nouns.

Word	Noun	Adjective	Verb	Adverb
Anas acuta	Yes	No	No	No
pin-tailed duck	Yes	No	No	No

As nouns, Anas acuta and pin-tailed duck are synonyms defined as:

Anas acuta and pin-tailed duck: long-necked river duck of the Old and New Worlds having elongated central tail feathers

Other synonyms of Anas acuta include pintail.

Anas acuta (noun)	pin-tailed duck (noun)
long-necked river duck of the Old and New Worlds having elongated central tail feathers	long-necked river duck of the Old and New Worlds having elongated central tail feathers