Baryonyx can stun them for some reason. Lure an Alpha Carno to the water and then stunlock them, better if you have an aquatic tame ready or if it's in shallow waters where the alpha carno (and you) will swim but your other tames won't.

If you ride a trike you can kill with knockback, just be on level ground or above it. Right before you kill it hop off your mount, whistle passive, then kill it yourself to get lots of exp. Hope this helps, enjoy!😁

To get it:

Search for alpha carno

Use a therizino or spino or Rex (can use baryonyx if underwater)

Kill it:they aren't tameable unless u hack the system

Boom you got the trophy

Get the Longneck Rifle and some simple rifle ammo and with your Argentavis or Pteranodon fly to the most tallest rock where he can’t damage you and your pet shot that mf and that’s the most easy way