Pet Specs are now locked to the pet types, so Turtles are all Tenacity, Dogs/Cats are all Ferocity, Birds are Cunning, etc.
The only major difference between specs is the passive both you and your pet get (Leech, Stamina, and Speed respectively to F/T/C), as well as a utility cooldown your pet grants you (Heroism/Blood Lust, Damage Reduction, or Master's Call, again respective to F/T/C). The pets themselves can tank/damage like any other with slight differences, like turtles being able to tank a bit better cuz of Shell Shield, but no more do you HAVE to have a Tenacity pet for tanking.
... at least that's what was said and intended, but I don't see any passives like Blood of the Rhino or Barbed Collar on the pet spellbook so idk.