[cripplecreek]

A fossil discovered in Montana has given new momentum to the hypothesis that dinosaurs were thriving right up until a devastating meteor hit Earth 65 million years ago, causing their extinction.

I'm not sure finding one is evidence that they were "thriving". I'm of the mind that they were on their way to extincton and the asteroid impact was the tipping point.

[MHGinTN]

Well, a 65 miles across rock racing at the earth at 17,000 miles per hour plus would cause a rather sever stress on the animals and their environment.

[UCANSEE2]

I'm of the mind that they were on their way to extincton

I agree.

The Earth used to be smaller, spun faster, and a higher oxygen content. Those things enabled the reptiles and mammals to grow to such extreme sizes. The Land masses might have been changing (moving up or down) and the oceans relocating much more than they do now.

Loss of breeding grounds, or feeding spots, and maybe viruses could have helped wipe them out. Over time, it became harder to carry their weight as gravity increased.

So... they went 'extinct'. Life is life. It just has different forms at different times to match the living conditions. Forms go extinct. Life doesn't.

[JimSEA]

You would expect to see lots of fossils right up to the boundary, in fact, if all died at once there should be ample evidence. I would agree with you that the asteroid was the last straw. However the lack of fossils just after the strike shows a widespread extinction combination of events.