Spread-eagled on an ice floe the pytheron appears lumpish and ungainly
The pytheron, although totally unrelated, has an appearance similar to the ancient crawling seals and sea lions.
The pytheron, Thalassomus piscevorus, is a carnivorous, semiaquatic, pinniped-like relative of the predator rats from the Polar Ocean, from After Man: A Zoology of the Future. There are a few different species of pytheron.
Pytherons prey on flightless auks, and also on fish, during the spring months. They occupy the same ecological niche that the seals occupied in earlier times and like them have developed streamlined blubbery bodies and fin-shaped limbs.
In the water it is swift and graceful, swimming like a penguin.