Perhaps they never left.

I haven't read through the entire 11 pages of this thread, so I apologize if this has already been brought up, but... why would these dinosaurs evolve into a humanoid shape? (I'm going off of the image here) Why would they choose a breeding partner with stubby legs and gimped claws that would effectively make it harder for their offspring to hunt?

In my mind, if these dinosaurs were to evolve into a sentient species, they would keep their general shape but obtain bigger brains and stronger arms/more nimble fingers to craft things with.

As for there having been an advanced, space-faring dinosaur species on our Earth - the idea sounds fun, but wouldn't we find relics? If they were truly advanced, they would probably have populated the entire planet, like us, so a meteor wouldn't have destroyed every single city. And surely, there would be graveyards with thousands of their bodies being excavated? If they were fleeing from some catastrophic event, I doubt they would have time to bring all their dead with them.

Also, wouldn't there be ancient satellites orbiting our planet? I'm not an expert, but I'm pretty sure our early forays into space left a lot of junk circling the Earth. Although, I suppose you could say that they would crash back down after a few hundred/thousands/millions/etc. of years.

Good Thread and nicely Put. I like the way of your thinking. Though it ishard to believe, but who knows there might be a chance for this too..

why would these dinosaurs evolve into a humanoid shape?
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we "supposedly" evolved from a monkey or a chimpanzee,so why would'nt they?

What renders this theory unprobable is the complete absence of closely related and precursor species in the fossil record
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What if that fossil record is a mile or two underground,or even just 1,000ft? Then we would never even find it

Until now I had always thought of dinosaurs as having brains that function much as modern day toads, but this thread sure has me thinking otherwise! I'm sure if dinosaurs are returning to their home planet, they will have prepared themselves well in advance to have to deal with possibly many different species that might have advanced way farther ahead of what they were when the dinosaurs left.
Since it is us humans they will have to deal with, they certainly won't have much competition as far as placement on the evolutionary scale goes! The one thing that bothers me more than anything else, is that will be our knee-jerk reaction to try killing them before we even know their intentions.
And to think we really do believe ourselves to be an intelligent and highly developed species! Sure we are!
I thank you very much for the "Food for thought"! I didn't realize just how hungry I was!

A species of advanced dinosaur escaped the destruction of the yucatan asteroid dy leaving the earth in starships and when they returned the remaining species of dinosaurs had been destroyed and gone extinct and they found a new species had arisen on earth...Humans.

If these advanced dinosaurs had left earth in spaceships,on a voyage to our closest galaxy andromeda,at just under the speed of light for say 10,000 years...Many millions of years would have gone by on earth...

We don't know the life span of these reptilians and they could have been in hibernation on-board their spaceships and or they could have bred along the way...

And that's why there are reptilians being reported by witnesses onboard the ufo's and flying saucers...

keep in mind that modern humans have been walking around earth for only about 200,000 years and we have gone from, the horse drawn carriage -1900, to the first nuclear powered aircraft carrier- 1961, in only 60 years!

And dinosaurs existed for hundreds of millions of years. More than enough time for at least one species to have reached an advanced state of intelligence and technology...