Plotopteridae

Plotopterids Temporal range: Eocene – Miocene ~Priabonian–Burdigalian PreꞒ Ꞓ O S D C P T J K Pg N
Copepteryx
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Suliformes
Family:	†Plotopteridae Howard, 1969
Genera
†Empeirodytes †Phocavis †Plotopterum †Stemec †Stenornis †Tonsalinae Mayr & Goedert, 2018 †Copepteryx †Hokkaidornis †Klallamornis †Olympidytes †Tonsala

Plotopteridae

Their fossils have been found in California, Oregon,^[9] Washington,^[10][11] British Columbia,^[12] Hokkaido, Tōhoku, Chūbu, Kyushu.^[13] They seem to have evolved on arctic islands during the mid-Eocene, spreading southwards with the formation of kelp forests ^[14] They ranged in size from that of a large cormorant (such as a Brandt's cormorant), to very large size, with femur length two times longer than emperor penguin.^[2] They had shortened wings optimised for underwater wing-propelled pursuit diving (like penguins or the now extinct great auk), and a body skeleton similar to that of the darter.

The second species to be named from rocks along the eastern Pacific Ocean was Tonsala hildegardae^[15] from the late Oligocene lower part of the Pysht Formation in Washington State. More fossils of T. hildegardae have since been described ^[16][17] and included some of the first known examples of borings made by the marine bone-eating worm Osedax in bird bones.^[18]

The earliest known member of the family, Phocavis maritimus lived in the late Eocene, but most of the known species lived during Oligocene time, becoming extinct in the early to mid-Miocene. That they became extinct at the same time as the giant penguins of the Southern Hemisphere, which also coincided with the radiation of the seals and dolphins, has led to speculation that the expansion of marine mammals was responsible for the extinction of the Plotopteridae, though this has not been formally tested.

References