Quote Originally Posted by Keravath View Post
In terms of summoning, the Druid specifies how many creatures and what CR they will be as per the spell. The DM can then decide the shape that the spirits take.

However, it is important for the DM to note that, like find familiar, conjure animals and several other “summoning” spells do NOT summon actual creatures of the specific type, the spells conjure fey, fiend or celestial spirits (type chosen by the caster) that take on the form and stat block of the specific species.

There is no requirement that the form of the conjured creature actually exists in the local environment somewhere. The DM has latitude in what form the spirits take because it is possible that the game world doesn’t contain all possible beasts, fey or other forms. However, whether or not the creature exists locally is not a requirement for the spell or what forms the spirits take.
Very true. :)

With that said, I found several DM still using that "constraint" on the premises that since you're calling spirits to take the form of animals, it should be affected a bit by the environment.
Agreed that this is a totally personal point of view though.

Nothing prevents DM from allowing pteranodons appearing above ocean. ^^