tube-nosed bat vs megabat

tube-nosed bat and megabat both are nouns.

Word	Noun	Adjective	Verb	Adverb
tube-nosed bat	Yes	No	No	No
megabat	Yes	No	No	No

As nouns, megabat is a hypernym of tube-nosed bat; that is, megabat is a word with a broader meaning than tube-nosed bat:

tube-nosed bat: any of various fruit bats of the genus Nyctimene distinguished by nostrils drawn out into diverging tubes
megabat: large Old World bat of warm and tropical regions that feeds on fruit

Other hypernyms of tube-nosed bat include fruit bat.

tube-nosed bat (noun)	megabat (noun)
any of various fruit bats of the genus Nyctimene distinguished by nostrils drawn out into diverging tubes	large Old World bat of warm and tropical regions that feeds on fruit