It's an interesting interpretation, but I don't think Pampush is arguing that a trait must be present in a common ancestor in order to have a single name. He's

It's an interesting interpretation, but I don't think Pampush is arguing that a trait must be present in a common ancestor in order to have a single name. He's certainly familiar with parallel evolution, usually the basic examples given are the bat's wings and cephalopod's eyes, maybe even more striking than the insect hair example. He says it's fundamentally different, and I think I can see how that's the case, seeing how elephants can actually close their mouth/trunk onto their chin (giving it an obvious use), and also considering the structural difference where the elephant's chin is a direct continuation of the line where teeth are resting. It's more of an extended lower jaw than a separate protuberance like in humans. That being said, I'll keep on calling it a chin.