Hello, I am trying to find out if there is a common ansestor that unites Gastropods and tetrapods. Has an ansestor been found where both animal groups unite in their evolution?

If there is, what is the name of it?

All animals have a common ancestor, though for such distantly related groups as gastropods and tetrapods, it will be very far back indeed, and there will be a lot of groups in between (fish for example).


Unless I'm mistaken, you'd have to go right back to the bilateria to get a common ancestor of Gastropods an tetrapods:

http://en.wikipedia.org/wiki/Bilateria

Maybe a little up the tree from there...