The porpin, Stenavis piscivora, a medium-sized pelagornid from coastal Antarctica, in the Southern Ocean.
Freed of the necessity to come ashore, pelagornids have become completely marine and ultimately given rise to this completely new order of marine birds, of which the porpin is the commonest surviving example.
The porpin, like most of its clade, is a fish-eater. Its distinguishing feature from other species (like the larger vortex) is a long, serrated beak that enables it to catch larger fish than would otherwise be possible. So successful has it been that it has remained virtually unchanged for the last 40 million years.