Ichthyostega concept art
Ichthyostega - is an extinct genus of limbed tetrapodomorphs from the Late Devonian of what is now Greenland. It was among the earliest four-limbed vertebrates ever in the fossil record and was one of the first with weight-bearing adaptations for terrestrial locomotion.
Hell on earth[]
Ichthyostega wouldn't appear until the end of the episode, and it is depicted feeding and hunting on surviving Bothriolepis.