Plotopteridae is an extinct family of flightless seabirds with uncertain placement, generally considered as member of order Suliformes. They exhibited remarkable convergent evolution with the penguins, particularly with the now extinct giant penguins. That they lived in the North Pacific, the other side of the world from the penguins, has led to them being described at times as the Northern Hemisphere's penguins, though they were not closely related. More recent studies have shown, however, that the shoulder-girdle, forelimb and sternum of plotopterids differ significantly from those of penguins, so comparisons in terms of function may not be entirely accurate. Plotopterids are regarded as closely related to Anhingidae (darters) and Phalacrocoracidae (cormorants). On the other hand, there is a theory that this group may have a common ancestor with penguins due to the similarity of forelimb and brain morphology. However, the endocast morphology of stem group Sphenisciformes differs from both Plotopteridae and modern penguins.
Limnofregata is an extinct genus of primitive frigatebird. The two known species were described after fossils from the Early Eocene Green River Formation of Wyoming. A number of good complete and partial skeletons, some with feather impressions, are known of the type species, Limnofregata azygosternon, and L. hasegawai is known from two skulls and most of one torso.
Osteodontornis is an extinct seabird genus. It contains a single named species, Osteodontornis orri, which was described quite exactly one century after the first species of the Pelagornithidae was. O. orri was named after the naturalist Ellison Orr (1857-1951).
The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dating between the Early Paleocene and the Pliocene-Pleistocene boundary.
Cyphornis is a genus of the prehistoric pseudotooth birds. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.
Palaeochenoides is a genus of the prehistoric pseudotooth birds of somewhat doubtful validity. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.
Pelagornis is a widespread genus of prehistoric pseudotooth birds. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.
Pseudodontornis is a rather disputed genus of the prehistoric pseudotooth birds. The pseudotooth birds or pelagornithids were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty. Up to five species are commonly recognized in this genus.
Hokkaidornis is an extinct genus of penguin-like plotopterid from the Late Oligocene of Hokkaido, Japan.
Bathornis is an extinct lineage of birds related to modern day seriemas, that lived in North America about 37–20 million years ago. Like the closely related and also extinct phorusrhacids, it was a flightless predator, occupying predatory niches in environments classically considered to be dominated by mammals. It was a highly diverse and successful genus, spanning a large number of species that occurred from the Priabonian Eocene to the Burdigalian Miocene epochs.
Spheniscus muizoni is an extinct species of banded penguins that lived during the early Late Miocene in what is now Peru, South America. The species, the earliest member of the extant genus, was described in 2007 by Ursula B. Göhlich based on fossils found in the fossiliferous Pisco Formation of the Pisco Basin, southwestern Peru.
Plotopterum is an extinct genus of flightless seabird of the family Plotopteridae, native to the North Pacific during the Late Oligocene and the Early Miocene. The only described species is Plotopterum joaquinensis.
Tonsala is an extinct genus of Plotopteridae, a family of flightless seabird similar in biology with penguins, but more closely related to modern cormorants. The genus is known from terrains dated from the Late Oligocene of the State of Washington and Japan.
Phocavis is an extinct genus of flightless seabird, belonging to the family Plotopteridae, and distantly related with modern cormorants. Its fossils, found in the Keasey Formation in Oregon, are dated from the Late Eocene.
Stemec is an extinct genus of Plotopteridae, a family of flightless seabird similar in biology with penguins, but more closely related to modern cormorants. The genus is known from terrains dated from the Late Oligocene Sooke Formation of British Columbia
Olympidytes is an extinct genus of Plotopteridae, a family of large, flightless marine bird superficially similar to modern penguins but more closely related to cormorants and gannets. It lived during the Late Eocene or the Early Oligocene, in what is today the State of Washington and Japan.
Empeirodytes is an extinct genus of Plotopteridae, a family of large flightless bird known from the Late Eocene to the Early Miocene of the West Coast of the United States, British Columbia and Japan. Remains associated with Empeirodytes have been found in Oligocene rocks of the Ashiya Group, on the islands of Ainoshima and Kaijima, near Kitakyushu, Japan.
Stenornis is an extinct genus of Plotopteridae, a family of large-sized, flightless seabirds native from the North Pacific during the Paleogene and the earliest Neogene. The remains of Stenornis have been found in Oligocene rocks of the Jinnobaru Formation on Hikoshima and the Ashiya Group on Ainoshima, Japan.
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 in the North American continent. The first fossil remains attributed to the taxon were collected in 1983, although the genus wasn't described until 2016.
