I never heard of a species of animal that was half-way between a monkey and a man.
Of course you have ... you only pretend you haven't ...
And those are only the ones we've found. Even today, less than 25% of species on earth have been identified. How many thousands, hundreds of thousands, of distinct species have evolved and gone extinct in the past 20 million years?
At some point in time, a common ancestor of both humans and great apes existed. Some of it's descendants became the tree that lead to apes, some became the tree that led to humans.
At some point in the future, if humans don't go extinct, a new branch will emerge that will lead to another type of human.