Klallamornis

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 was not 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. 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 appearance 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.

Etymology The genus name, Klallamornis, was given after the Klallam culture, native of the area of the Olympic Mountains where terrains associated with the Pysht Formation and the Makah Formation have yielded the first identified remains of the genus.

History

History of research

Early discoveries and research Fossils associated with Klallamornis were among the earliest known remains of plotopterids; recognition of specimen attributed to the genus as a new species or a new genus of plotopterid dates from the early 2000s. In 1983, one of the specimens associated with K. buchanani was collected by James L. Goedert. In 2002, the first recovered specimens, including the "Whiskey Creek plotopterid" (UWBM 86869), one of the most ancient plotopterids known, another partial skeleton and an isolated tarsometatarsus, from the younger Jansen Creek member of the Makah Formation, collected by James L. Goedert, were identified as remains from one or several undescribed species of plotopterids by Goedert and John Cornish. In 2011, Gareth J. Dyke, Xia Wang and Michael B. Habib described a new species of large plotopterid based on a partial, although relatively well-preserved skeleton from the Oligocene of the Pysht Formation, UWBM 86875, as Tonsala buchanani, the second species from the genus Tonsala to be described. Alongside the holotype, they referred to the newly described species the three indeterminate plotopterid specimens collected by Goedert in the Makah Formation. In 2015, Goedert, Gerald Mayr and Olaf Vogel speculated that the remains associated with Tonsala buchanani may represent several species, on account of the lapse of 5 million years between the Whiskey Creek plotopterid and the holotype, and that some morphological characters indicated that T. buchanani differed at the genus level from T. hildegardae, the type species of Tonsala.

Description of the genus In 2016, Goedert and Mayr described a new genus and two new species of plotopterids : Klallamornis abyssa, the type species of the new genus, based on a partial skeleton collected in 1991 by Goedert, SMF Av 610, and dated from the Late Oligocene of the Pysht Formation, with two other specimens, an isolated and fragmentary tibiotarsus and a coracoid, respectively collected in 1988 by Goedert and in 1985 by M. J. Berglund, both from the Jansen Creek Member of the Makah Formation, referred to the genus; and the tentatively assigned ?Klallamornis clarki, much larger, but only known from a tarsometatarsus collected in 1988 in the Jansen Creek Member of the Makah Formation by R. L. Clark. In this article, they expressed additional concerns against the assignation of specimens to T. buchanani and the assignation of the species to the genus Tonsala, and reflected, although without more action, at the possibility that the Whiskey Creek plotopterid may represent another specimen of ?K. clarki.

Recent works

More recently, Mayr and Goedert reviewed the remains associated with Tonsala buchanani; they concluded that those remains belonged to an animal closer to Klallamornis, and recombined the species as Klallamornis buchanani. They also referred to the genus several new specimens. They stripped K. buchanani of the totality of its referred material aside from the holotype, and referred to it another specimen from the same deposits. Three new specimens were assigned to ?K. clarki, and the Whiskey Creek plotopterid was tentatively assigned to the same species as cf ?Klallamornis clarki. They tentatively assigned to the genus another undescribed species, based on another specimen once attributed to K. buchanani, noting however that the specimen could also belong to the genus Olympidytes, or to a new genus, as cf. Klallamornis or Olympidytes.

Description

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