| Klallamornis | |
|---|---|
| |
| Fossil material referred to K. buchanani, cf. ?K. clarki and the UWBM 86871 species | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Suliformes |
| Family: | †Plotopteridae |
| Subfamily: | †Tonsalinae |
| Genus: | †Klallamornis Mayr & Goedert, 2016 |
| Type species | |
| Klallamornis abyssa Mayr & Goedert, 2016
| |
| Species | |
| |
| Synonyms | |
| |
Klallamornis is an extinct genus of Plotopteridae, a family of large, flightless birds related to modern cormorants, darters, gannets, and boobies. This genus included the largest North American plotopterids. Its remains can be found in Late Eocene to Late Oligocene rocks from the Makah Formation, the overlying Pysht Formation and the Lincoln Creek Formation of the State of Washington. During its existence, Klallamornis was the largest plotopterid on the North American continent. The first fossil remains attributed to the taxon were collected in 1983, although the genus wasn't described until 2016.
Klallamornis was a large pelagic seabird. Despite being unable to fly, its wings were heavily built and muscular, a consequence of wing-propelled diving adaptations.[1] It was superficially similar with modern penguins, despite being only distantly related to them.
The genus has a complicated taxonomy; of the three species published, two of them, K. buchanani and K. abyssa might be synonymous. K. buchanani was only recently assigned to the genus, and was referred until 2021 to the related genus Tonsala. ?K. clarki is only tentatively referred to the genus. One of the specimens assigned to ?K. clarki, generally nicknamed "Whiskey Creek plotopterid" in earlier paper after the locality where it was discovered, might be the oldest known plotopterid, dating as far back than the Priabonian.
Klallamornis appeared during a period of global cooling, marked by the apparition of kelp forests in the North Pacific and a renewal in volcanism along the coast of the Pacific Northwest, creating a chain of volcanic islands in the area, a perfect area for the reproduction of large flightless birds. It coexisted with some of the earliest whales in the North Pacific, the large semi-aquatic desmostylians, and its close relatives Tonsala and Olympidytes.