How to find a high level spino or baryonyx on mobile:

Just north of south zone 2 there is a river. Head up river until you see the river branch off to your right (eastwards) near 78/60. Along this branch of the river spino and baryonyx spawn a lot. If you don’t see a good one just kill every fish in the river and come back. Just tamed a lvl 140 spino and lvl 145 baryonyx after doing this for about 2 hours.

Be careful tho this river has a lot of raptors and sometimes carnos and alpha raptors along its bank.