Are we somehow expecting to see evidence of chromosome change in the fossil record? Because that's the only thing I can at all see has not been explained here.
And if it is, here's the answer. DNA doesn't fossilize at all well.
"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"
"You can't erase icing."
"I can't believe it doesn't work! I found it on the internet, man!"