and the answer is probably
australopithecus, discovered and described by Raymond Dart in 1924
but this is a question from your course work ( on ahtropology ) and it is surprisingly moot - early Homo spp and australopithecus co -existed
and when they re examined the strata and the work Dart had done it was obvious that the conclusion cd have been made in the twenties - that the two existed side by side
Dart responded - oh yes we knew all that - we just thought if we published it no one wd believe us.
there was a now discredited line of English / British Anthropology which championed Piltdown man -a notorious fake. And in 1952 Keith a champion of it said; " I am now convinced... that Prof. Dart was right and that I was wrong."
and you dont often get that said in public ! !
You really must do your own homework
Prof Dart taught my father anatomy 1930