Kamuysaurus Temporal range: Early Maastrichtian, | |
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Known remains of Kamuysaurus | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | † Ornithischia |
Clade: | † Neornithischia |
Clade: | † Ornithopoda |
Family: | † Hadrosauridae |
Subfamily: | † Saurolophinae |
Tribe: | † Edmontosaurini |
Genus: | † Kamuysaurus Kobayashi et al., 2019 |
Type species | |
†Kamuysaurus japonicus Kobayashi et al., 2019 |
Kamuysaurus is a genus of herbivorous edmontosaurin saurolophine hadrosaurid dinosaur from Late Cretaceous Maastrichtian marine deposits of the Yezo Group (Hakobuchi Formation) in the Hobetsu area near the town of Mukawa, Hokkaido in Japan. [1] [2]
In 2003, amateur paleontologist Yoshiyuki Horita at the Shirafunezawa Creek discovered the tail of a euornithopod. An entire skeleton was in 2013 and 2014 uncovered by teams of the Hobetsu Museum and the Hokkaido University Museum. [1] The find was nicknamed Mukawaryu, [3] the "Dragon of Mukawa".
In 2019, the type species Kamuysaurus japonicus was named and described by Professor Yoshitsugu Kobayashi, Tomohiro Nishimura, Ryuji Takasaki, Kentaro Chiba, Anthony Ricardo Fiorillo, Kohei Tanaka, Tsogtbaatar Chinzorig, Tamaki Sato and Kazuhiko Sakurai. The generic name is derived from kamuy , meaning "deity" in Ainu, the language of the original inhabitants of Hokkaido. The specific name japonicus, "japanese" in Neo-Latin, refers to the provenance from Japan. [1]
The holotype, HMG-1219, has been found in a marine layer of the Hakobuchi Formation, part of the Yezo Group, dating from the early Maastrichtian, between 72.1 and 70.6 million years old. It consists of a nearly complete skeleton with skull, only missing the snout, parts of the sacral vertebrae and phalanges. [1] Containing over 60% of the skeletal elements and 80% of the bone mass, it is, together with the smaller skeleton of Fukuivenator , one of the most complete dinosaur skeletons found in Japan. [3] The bones were found on a surface of seven by four metres (23 by 13 ft) and were partially articulated, though sometimes damaged by erosion. The holotype represents an adult individual of at least nine years of age. It was likely washed into the sea as a carcass. [1]
Kamuysaurus was about eight metres (26 ft) long. From the width of its thighbone, its weight has been estimated at 4 or 5.3 tonnes (3.9 or 5.2 long tons; 4.4 or 5.8 short tons), dependent on its having been bipedal or quadrupedal respectively. [1] [3]
The describing authors indicated some distinguishing traits. Three of these were autapomorphies, unique derived characters. On the quadrate bone, the notch at the opening separating it from the quadratojugal bone, is located at a very low position, at three quarters of the shaft length measured from the top of the element. This is unique for the Hadrosauridae as a whole. The surangular bone of the lower jaw has only a short ascending branch, not reaching the coronoid process. The sixth tot thirteenth back vertebrae have neural spines that are inclined to the front. [1]
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The Yezo Group is a stratigraphic group in Hokkaido, Japan and Sakhalin, Russia which is primarily Late Cretaceous in age. It is exposed as roughly north–south trending belt extending 1,500 kilometres through central Hokkaido from Urakawa to Cape Sōya and Sakhalin from the south coast to Alexandrovsk-Sakhalinsky District. It consists of marine forearc basin sediments, typically turbiditic and bioturbated mudstones and sandstones with subordinate conglomerate primarily deposited on the continental shelf and slope of the ancient Yezo subduction margin. It forms a continuous depositional sequence with the Sorachi Group, which overlies the Horokanai Ophiolite. The sequence gradually shallows upwards with the terminal Hakobuchi Formation representing a fluvial-inner shelf environment.
The 89th Emperor's Cup began on September 19, 2009 and ended on January 1, 2010 with the final at National Stadium in Tokyo, Japan. Gamba Osaka won the title for two years in a row. Since Gamba already confirmed 2010 AFC Champions League berth, the last spot of ACL for J.League club is awarded to Sanfrecce Hiroshima, which finished as 4th place of 2009 J.League Division 1.
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The Hakobuchi Formation is a geological formation in Hokkaido, Japan. It is the uppermost unit of the Yezo Group, being early Maastrichtian in age. It consists of bioturbated glauconitic sandstones, siltstones and conglomerates with coaly mudstone and minor tuffite. It was deposited in a continental shelf setting. It is noted for its fossil content with the invertebrates mainly consisting of bivalves and ammonites. With vertebrates including the mosasaurs Mosasaurus hobetsuensis and Phosphorosaurus ponpetelegans. As well the sea turtle Mesodermochelys and the hadrosaurid dinosaur Kamuysaurus.
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Yoshitsugu Kobayashi is a Japanese vertebrate paleontologist. He is a professor and the assistant director in Hokkaido University Museum. His major achievements include the description and naming of several dinosaurs from Japan, for example, Kamuysaurus, Yamatosaurus and Paralitherizinosaurus. He is also a research affiliate of Perot Museum of Nature and Science, a member of Jurassic Foundation, a councilor of Palaeontological Society of Japan.