Saurgust day 10, Copepteryx hexeris.

Fossil Novembirb: Day 17

Some watercolour studies of Copepteryx, a large flightless seabird that was part of the now extinct group called Plotopterids. Plotopterids ranged in size from the size of a large cormorant to 2 meters long, and lived from the Eocene to the Miocene.

Copepteryx hexeris, a plotopterid bird from the Late Oligocene of Japan (~28-23 mya).

Known from around the North Pacific rim from about 33-15 million years ago, plotopterids were flightless diving birds which used their small but powerful wings to propel themselves through the water. They were convergently similar to penguins in body shape and lifestyle, but not actually closely related to them -- instead being relatives of gannets, cormorants, and anhingas.

Smaller plotopterids were about the size of modern cormorants, around 70cm long (2′4″), but the larger known genera like Copepteryx rivalled the southern giant penguins at around 1.8m (6′).