Dictionary.com Thesaurus.com

pterosaur vs. pterodactyl

pterosaur

[ter-uh-sawr] / ˈtɛr əˌsɔr /

noun

any flying reptile of the extinct order Pterosauria, from the Jurassic and Cretaceous periods, having the outside digit of the forelimb greatly elongated and supporting a wing membrane.

pterodactyl

[ter-uh-dak-til] / ˌtɛr əˈdæk tɪl /

noun

any of a number of genera of flying reptiles of the extinct order Pterosauria, from the Jurassic and Cretaceous periods, having a highly reduced tail and teeth and a birdlike beak.