One of Adam's first assignments was to name all the animals including the sea creatures and dinosaurs of course. We don't know how long this took but, as all witnesses know, the time period is crucial in working out the timing of Armageddon).
JW's don't necessarily think that dinosaurs had not already gone extinct by Adam's time. Something about the earth having much vegetation to balance the atmosphere, and dinosaurs to remove the vegetation, and then their need was over.
Also, "....as all witnesses know, the time period is crucial in working out the timing of Armageddon" !!!
Who told you that crap? All witnesses do not know a bunch of the doctrine. And all the stuff about when Adam was created and when the last creative day started/ended- that's stuff of Fred Franz' day. It has nothing to do with the supposed timing of Armageddon now, that's stuff of the overlapping generation.