Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Cladus: Saurischia
Cladus: Eusaurischia
Subordo: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Infraclassis: Aves
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Ornithuromorpha
Cladus: Carinatae
Parvclassis: Neornithes
Cohors: Neognathae
Cladus: Neoaves
Cladus: Aequornithes
Ordo: Pelecaniformes
Familia: †Plotopteridae
Genus: †Hokkaidornis
Species: †H. abashiriensis
Name
Hokkaidornis Sakurai, Kimura & Katoh, 2008: 90
Type species: Hokkaidornis abashiriensis [Sakurai, Kimura & Katoh, 2008: 90]
Etymology: Hokkaido + (Greek) ornis = bird [Sakurai, Kimura & Katoh, 2008: 90]
References
Primary references
Sakurai, K., Kimura, M. & Katoh, T. 2008. A new penguin-like bird (Pelecaniformes:Plotopteridae) from the Late Oligocene Tokoro Formation, northeastern Hokkaido, Japan. Oryctos 7: 83–94. PDF Reference page.
Links
Hokkaidornis – Taxon details on Fossilworks.
Hokkaidornis is an extinct genus of penguin-like plotopterid from the Late Oligocene of Hokkaido, Japan.[1]
History and etymology
The first Hokkaidornis remains were discovered in sediments dated from the Late Oligocene of the Tokoro Formation, near the city of Abashiri, in the Japanese island of Hokkaido, and had been identified as the remains of a yet-unidentified genus and species of plotopterid in 1998. In 2008, Kazuhiko Sakurai, Masaichi Kimura and Takayuki Katoh described the new genus and species Hokkaidornis abashiriensis, using as holotype the specimen AMP 44, a semi-complete skeleton lacking the skull.[1]
Etymology
The genus name, Hokkaidornis, is constructed from Hokkaido, the island in which the holotype was discovered, and the ancient Greek suffix -ornis, meaning "bird". The species name, abashiriensis, refers to the town of Abashiri, near which it was found ; the city name itself meaning "to be discovered in rock" in the native Ainu language.[1]
Description
Hokkaidornis was a large-bodied plotopterid, with estimated height of 1.3 metres (4.3 ft) and length of 1.7 metres (5.6 ft),[2] roughly the size of its relative Copepteryx hexeris. The anterior ends of the furcula are more reminiscent of those found in Anhinga than those of Phalacrocoracidae. The sternal end of the coracoid, only part of the coracoid preserved in the holotype specimen, had a more angular sterno-coracoidal process, differing it from Copepteryx and Tonsala. The well-preserved scapula was similar to that of Tonsala. The partially preserved humerus was more elongated than that of Tonsala, and had a shaft more sinuous than that of Copepteryx, and similar to that of Tonsala. The radius was flattened like in other plotopterid, while the ulna was the largest known for plotopterids. The pelvis shared similarities with those of modern anhingas. The femur was more robust than that of Tonsala, and had a more bowed shaft and a more bulbous head than those of both species of Copepteryx, although it resembled, as well than the tibiotarsus, those of some specimens referred tentatively to Copepteryx by Olson and Hasegawa. The patella was remarkably heavy. The tarsometatarsus was more robust and less elongated than in Phocavis, but was nearly undistinguishable to that of the paratype of C. hexeris, and quite similar to those of modern-day penguins.[1]
Paleobiology
Hokkaidornis had a well-developed trochlea cartilaginis tibialis on its tarsometatarsus, a character mostly known from hindlimb-propelled marine birds. That development may indicate that Hokkaidornis was not only adapted towards wing-propelled swimming like most other plotopterids, but also able to propel itself through water with its hindlimbs, a characteristic also present in its relative Olympidytes.[3]
The preservation of ripple marks on sandstones found in the vicinity of the holotype and the presence of the bivalves Periploma yokoyamai and Yoldia, the gastropod Turritella and the scaphopod Dentalium in association with the specimen indicates that Hokkaidornis lived in a shallow marine environment.[1]
References
Sakurai, K.; M. Kimura & T.A. Katoh (2008). "New penguin-like bird (Pelecaniformes; Plotopteridae) from the Late Oligocene Tokoro Formation, northeastern Hokkaido". Oryctos. 7: 83–94.
"博物館だより 2017年7月" (PDF). Ashoro Museum of Paleontology. July 2017.
Mori, H. & Miyata K. (2021). "Early Plotopteridae Specimens (Aves) from the Itanoura and Kakinoura Formations (Latest Eocene to Early Oligocene), Saikai, Nagasaki Prefecture, Western Japan". Paleontological Research. 25 (2): 145–159. doi:10.2517/2020PR018. S2CID 233029559.
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