The last outright fraud or hoax I can think of relating in any way to evolutionary theory was that fossil bird that was composed from the body of one creature and the tail of another. (Both being valid fossils individually.) That was, what, five or six years ago? Even that wasn't a nefarious evilutionist plot, but just some Chinese fossil merchant trying to make a few extra bucks. I don't know of any frauds or hoaxes touching on human evolution other than Piltdown.
Funny thing is, compared to most other scientific fields, evolutionary biology seems to have an unusually low rate of fraud and deception, as illustrated by the ancient dates of the examples that anti-evolutionists are able to dig up.
But then maybe this is explicable. Whatever the perceived "glamor" of the field, there isn't really much money involved in evolutionary biology, and fraud is usually about money in the end. Far and away the greatest number of frauds occur in biomedical science, and this is also where the most money is.
Piltdown man was most definitely not an evolutionist fraud. It was a phoney fossil that was seen almost immediately to be something that didn't beling in the human family tree. It's as if you were putting together your own genealogy, and someone slipped in some documents purporting to show that your great-great grandfather was a guy who lived and died on Borneo, and who never left that island. If nobody else in your family had ever been there, he would be a most unlikely ancestor. It would be a very strange and suspicious data point in your family tree.
Eventually, through solid research, you would discover your real ancestor; although you might never learn who had handed you the bogus information. This would not be evidence that you were claiming a false genealogy. Rather, you'd be a victim of someone who was trying to discredit you.
That's why I suspect that Piltdown man was a creationist fraud. The fossil never served any evolutionist purpose.
That was Archaeoraptor, announced October 99 and debunked in January 00. Yeah. I'm so old I remember the thread we did on it at the time.