A new member of the family Plotopteridae (Aves) from the late Oligocene of British Columbia, Canada

Abstract

The discovery of an avian fossil, in the upper Oligocene Sooke Formation rocks on southwestern Vancouver Island, British Columbia, is the first example from Canada of the Plotopteridae, an extinct family that lived in the North Pacific from the late Eocene to the early Miocene. The fossil is a nearly complete, well-preserved coracoid that exhibits the diagnostic features of the family. Stemec suntokum is described as a new genus and species for this family of extinct, wing-propelled diving birds. Coracoids are exceptionally informative bones that lie at the focus of forces acting on the shoulder where they play a major role in avian locomotory biomechanics. The coracoid of Stemec has an unusually narrow, conical shaft that differs fundamentally from the broad, flattened coracoids of other avian groups.

New early aeluroid carnivoran (Mammalia, Carnivora, Feliformia) from the classical palaeontological locality Valeč, the Czech Republic

“…Maridet et al 2013). Especially important is the locality Dětaň, described by Fejfar (Fejfar 1987;Mikuláš et al 2003;Fejfar & Kaiser 2005), who compared it to MP 21/22 localities from Western Europe and assigned it to the earliest Oligocene (MP 21), just after the "Grande Coupure". As discussed above, the exact age of the Valeč mandible is not known, but it seems most likely that it belongs to this early post-"Grande Coupure" migration wave recorded in Central Europe.…”

“…The carnivorous mammals within this assemblage are arctoids and hyaenodonts (Fejfar 1987). This fauna was buried in the basal layer of pyroclastic deposition in this area (Fejfar 1987;Mikuláš et al 2003;Fejfar & Kaiser 2005). But the contemporariness of these two localities can only be considered as probable from similar geological position, not proven.…”

New late Eocene and Oligocene plotopterid fossils from Washington State (USA), with a revision of “Tonsala” buchanani (Aves, Plotopteridae)

“…The Plotopteridae were penguin-like, flightless seabirds that inhabited the North Pacific Basin in the late Eocene and Oligocene and possibly survived into the middle Miocene. The fossil record of these birds has significantly increased in the past years and now includes four genera ( Copepteryx , Hokkaidornis , Empeirodytes , and Stenornis ) with five named species from Japan and six genera ( Phocavis , Tonsala , Olympidytes , Klallamornis , Plotopterum , and Stemec ) with eight named species from North America (Howard, 1969; Olson, 1980; Goedert, 1988; Olson and Hasegawa, 1996; Sakurai et al, 2008; Kaiser et al, 2015; Mayr and Goedert, 2016; Ohashi and Hasegawa, 2020). Plotopterum and Olympidytes have also been tentatively recognized from rocks in Japan (Hasegawa et al, 1977; Olson and Hasegawa, 1985; Mori and Miyata, 2021).…”

“…In North America, plotopterid fossils were found in strata dating to the earliest Miocene in California (USA) and late Oligocene in British Columbia (Canada), which yielded the holotypes of Plotopterum joaquinensis Howard, 1969 and Stemec suntokum Kaiser, Watanabe, and Johns, 2015, respectively (Howard, 1969; Kaiser et al, 2015). The type locality for P. joaquinensis is in the Pyramid Hill Sand Member of the Jewett Sand and is considered to be earliest Aquitanian or earliest Miocene in age (Shimada et al, 2014; contra Kaiser et al, 2015, who assumed a late Oligocene age). One of the geochronologically earliest North American plotopterids, Phocavis maritimus Goedert, 1988, is from the late Eocene Keasey Formation in Oregon (Goedert, 1988).…”

Comparative osteology of the penguin‐like mid‐Cenozoic Plotopteridae and the earliest true fossil penguins, with comments on the origins of wing‐propelled diving

“…Some of these, such as Copepteryx Olson & Hasegawa, 1996 and Hokkaidornis Sakurai et al., 2008 (Oligocene, Japan), and Tonsala Olson, 1980, Olympidytes Mayr & Goedert, 2016, and Klallamornis Mayr & Goedert, 2016 (late Eocene and Oligocene, Washington State, USA), are represented by partial skeletons and their osteology is fairly well known. By contrast, the taxa Plotopterum Howard, 1969 (early Miocene, California, USA), Phocavis Goedert, 1988 (late Eocene, Oregon, USA), and Stemec Kaiser, Watanabe, & Johns, 2015 (late Oligocene, British Columbia, Canada) are only based on single bones. In fact, the coracoids that form the holotypes of Stemec suntokum Kaiser, Watanabe, & Johns, 2015 and Plotopterum joaquinensis Howard, 1969 and the holotypical tarsometatarsus of Phocavis maritimus Goedert, 1988 distinctly differ from the corresponding bones of Tonsala , Olympidytes , Klallamornis , Copepteryx , and Hokkaidornis in plesiomorphic features, and the latter five taxa were assigned to the new plotopterid subclade Tonsalinae by Mayr and Goedert (2018).…”