Pithecanthropus erectus vs Pithecanthropus

Pithecanthropus erectus and Pithecanthropus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pithecanthropus erectus	Yes	No	No	No
Pithecanthropus	Yes	No	No	No

As nouns, Pithecanthropus erectus and Pithecanthropus are synonyms defined as:

Pithecanthropus erectus and Pithecanthropus: former genus of primitive apelike men now Homo erectus

Other synonyms of Pithecanthropus erectus include genus Pithecanthropus.

Pithecanthropus erectus (noun)	Pithecanthropus (noun)
former genus of primitive apelike men now Homo erectus	former genus of primitive apelike men now Homo erectus