pterodactyl vs pterosaur

pterodactyl and pterosaur both are nouns.

Word	Noun	Adjective	Verb	Adverb
pterodactyl	Yes	No	No	No
pterosaur	Yes	No	No	No

As nouns, pterosaur is a hypernym of pterodactyl; that is, pterosaur is a word with a broader meaning than pterodactyl:

pterodactyl: extinct flying reptile
pterosaur: an extinct reptile of the Jurassic and Cretaceous having a bird-like beak and membranous wings supported by the very long fourth digit of each forelimb

Other hypernyms of pterodactyl include flying reptile.

pterodactyl (noun)	pterosaur (noun)
extinct flying reptile	an extinct reptile of the Jurassic and Cretaceous having a bird-like beak and membranous wings supported by the very long fourth digit of each forelimb