Apatosaurus excelsus vs apatosaur

Apatosaurus excelsus and apatosaur both are nouns.

Word	Noun	Adjective	Verb	Adverb
Apatosaurus excelsus	Yes	No	No	No
apatosaur	Yes	No	No	No

As nouns, Apatosaurus excelsus and apatosaur are synonyms defined as:

Apatosaurus excelsus and apatosaur: huge quadrupedal herbivorous dinosaur common in North America in the late Jurassic

Other synonyms of Apatosaurus excelsus include apatosaurus, brontosaur, brontosaurus, thunder lizard.

Apatosaurus excelsus (noun)	apatosaur (noun)
huge quadrupedal herbivorous dinosaur common in North America in the late Jurassic	huge quadrupedal herbivorous dinosaur common in North America in the late Jurassic