Different critter, and wrong demonym. It's "australopithecine", I believe. P.S.: Here you go: https://www.merriam-webster.com/dictionary/pithecanthropus I was particularly leaning into the "extinct primates intermediate between man and the anthropoid apes" part of the definition.
Kudos on spending the time to link to explanations of those things. There are people just up-thread who very likely need a step-by-step guide.