Atrapado, if you watch a child from birth to old age, at what minute did he become an adult? Could you specify even an hour, or a day? A month? Even a year? Tiny incremental changes that even over 70 years are not observable in real time can't be pinned down.
We evolved as human over hundreds of thousands of years, our ancestors going back millions. Just as there is no day where a baby suddenly becomes an adult, there is no point where BANG human ancestors became human. We still have their DNA and some traits to this day.
75% of people have a plamaris longus muscle in their hand and wrist, useful for holding onto branches. It simply does not work how you imagine it does, making your suggestion 100% impossible.
It isn't that we are pissing on your bonfire, I like how you have thought about it, but biology and evolution just dont work in such a clean cut, linear fashion as would be required by your suggestion. The reason we dont need fossils anymore in studying evolution,,is because all organisms have their ancestors coding in every cell, in the DNA. We have coding for tails, webbed hands, our organs even distribute as our ancestor fish did, making our anatomy innnefficiently placed. So from fish to human, sticking a flag in a point of time or set of genes doesn't help. Add to that we are still evolving right now, so even if we did what you said (though impossible) it would change instantly as we evolve at every generation, but all at a different rate and in wildly different ways, depending on our enviroment.