What major evolutionary milestone does Eryops represent among early vertebrates?

Answer

Solidifying the vertebrate foothold in terrestrial ecosystems

As a substantial tetrapod, *Eryops* represented an evolutionary step that solidified the vertebrate foothold in terrestrial ecosystems, even though it remained tied to water.

What major evolutionary milestone does Eryops represent among early vertebrates?
extinctamphibianPrehistoricPermianeryops