[Astromancer]

Originally Posted by tshiggins

Better yet, also make them able to be domesticated (if pretty stupid and sometimes ill-tempered) and willing to take riders and act as draft animals.

Suddenly, much of the huge advantage held by Europeans disappears, because the American Indians had available to them a source of tremendous animal muscle power, for thousands of years.

Agriculture is far more advanced, widespread and productive (even though somewhat hamstrung by the north-south orientation of the topography of the New World, if Jared Diamond's hypothesis is used), and construction and mining, as well as military capabilities, increase tremendously.

Throw in some diseases that manage to jump from dino to humans, against which Europeans have no immunity, and the sudden contact between the two biomes unleashes chaos, worldwide.

This is a grand idea, but it belongs on the Alternate world's thread so that you can get the love you deserve.