Kamuysaurus

Last updated

Kamuysaurus
Temporal range: Early Maastrichtian, 72.1–70.6  Ma
O
S
D
C
P
T
J
K
Pg
N
Holotype skeleton of Kamuysaurus.jpg
Known remains of Kamuysaurus
Scientific classification OOjs UI icon edit-ltr.svg
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]

Contents

Discovery

Skull elements Kamuysaurus skull.jpg
Skull elements

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]

Description

Life restoration Kamuysaurus japonicus.png
Life restoration

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]

Size comparison Kamuysaurus Scale.svg
Size comparison

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]

Related Research Articles

<span class="mw-page-title-main">Ornithomimosauria</span> Extinct clade of theropod dinosaurs

Ornithomimosauria are theropod dinosaurs which bore a superficial resemblance to the modern-day ostrich. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous Period of Laurasia, as well as Africa and possibly Australia. The group first appeared in the Early Cretaceous and persisted until the Late Cretaceous. Primitive members of the group include Nqwebasaurus, Pelecanimimus, Shenzhousaurus, Hexing and Deinocheirus, the arms of which reached 2.4 m (8 feet) in length. More advanced species, members of the family Ornithomimidae, include Gallimimus, Struthiomimus, and Ornithomimus. Some paleontologists, like Paul Sereno, consider the enigmatic alvarezsaurids to be close relatives of the ornithomimosaurs and place them together in the superfamily Ornithomimoidea.

<i>Edmontosaurus</i> Hadrosaurid dinosaur genus from Late Cretaceous US and Canada

Edmontosaurus, with the second species often colloquially and historically known as Anatosaurus or Anatotitan, is a genus of hadrosaurid (duck-billed) dinosaur. It contains two known species: Edmontosaurus regalis and Edmontosaurus annectens. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian age of the Cretaceous period 73 million years ago, while those of E. annectens were found in the same geographic region from rocks dated to the end of the Maastrichtian age, 66 million years ago. Edmontosaurus was one of the last non-avian dinosaurs to ever exist, and lived alongside dinosaurs like Triceratops, Tyrannosaurus, Ankylosaurus, and Pachycephalosaurus shortly before the Cretaceous–Paleogene extinction event.

<i>Garudimimus</i> Ornithomimosaur genus from the Late Cretaceous

Garudimimus is a genus of ornithomimosaur that lived in Asia during the Late Cretaceous. The genus is known from a single specimen found in 1981 by a Soviet-Mongolian paleontological expedition in the Bayan Shireh Formation and formally described in the same year by Rinchen Barsbold; the only species is Garudimimus brevipes. Several interpretations about the anatomical traits of Garudimimus were made in posterior examinations of the specimen, but most of them were criticized during its comprehensive redescription in 2005. Extensive undescribed ornithomimosaur remains at the type locality of Garudimimus may represent additional specimens of the genus.

<span class="mw-page-title-main">Bayan Shireh Formation</span> Geological formation in Mongolia

The Bayan Shireh Formation is a geological formation in Mongolia, that dates to the Cretaceous period. It was first described and established by Vasiliev et al. 1959.

<i>Nipponosaurus</i> Hadrosaurid dinosaur genus from Late Cretaceous Asia

Nipponosaurus is a lambeosaurine hadrosaur from sediments of the Yezo Group, in Sinegorsk on the island of Sakhalin, which was part of Japan at the time of the species' classification. The type and only species is N. sachalinensis, known only from a single juvenile specimen discovered in 1934 and named in 1936, by Takumi Nagao, with further material of the same individual found in 1937. Since then, the taxon has been largely ignored, and its validity has been doubted, with synonymy with other Asian hadrosaurs or status as a nomen dubium being suggested. Redescriptions from 2004 and 2017, however, have supported recognition as a distinct species. Dating the only specimen has been difficult, but based on associated mollusc taxa, the species likely lived sometime in the upper Santonian or lower Campanian, around 80 million years ago.

<span class="mw-page-title-main">Judith River Formation</span> Fossil-bearing geologic formation in Montana, part of the Judith River Group

The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the Late Cretaceous, between 79 and 75.3 million years ago, corresponding to the "Judithian" land vertebrate age. It was laid down during the same time period as portions of the Two Medicine Formation of Montana and the Oldman Formation of Alberta. It is an historically important formation, explored by early American paleontologists such as Edward Drinker Cope, who named several dinosaurs from scrappy remains found here on his 1876 expedition. Modern work has found nearly complete skeletons of the hadrosaurid Brachylophosaurus.

<span class="mw-page-title-main">Nemegt Formation</span> Geological formation in Mongolia

The Nemegt Formation is a geological formation in the Gobi Desert of Mongolia, dating to the Late Cretaceous. The formation consists of river channel sediments and contains fossils of fish, turtles, crocodilians, and a diverse fauna of dinosaurs, including birds.

<i>Mesodermochelys</i> Extinct genus of turtles

Mesodermochelys is an extinct genus of sea turtle known from the Campanian to the Maastrichtian of what today is Japan. One species is known, the type species M. undulatus; it was given its binomial name by Ren Hirayama and Tsutomu Chitoku in 1996. Studies of its skull indicate that it was a primitive member of the Dermochelyidae that was closely related to the Protostegidae. It has been described as the best representative of Mesozoic dermochelyids.

<span class="mw-page-title-main">Prince Creek Formation</span> Geological formation

The Prince Creek Formation is a geological formation in Alaska with strata dating to the Early Maastrichtian stage of the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.

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.

<i>Phosphorosaurus</i> Extinct genus of lizards

Phosphorosaurus is an extinct genus of marine lizard belonging to the mosasaur family. Phosphorosaurus is classified within the Halisaurinae subfamily alongside the genera Pluridens, Eonatator, and Halisaurus.

<i>Gobivenator</i> Extinct genus of dinosaurs

Gobivenator is an extinct genus of troodontid theropod dinosaur known from the late Campanian Djadokhta Formation of central Gobi Desert, Mongolia. It contains a single species, Gobivenator mongoliensis. G. mongoliensis is known from a single individual, which represents the most complete specimen of a Late Cretaceous troodontid currently known.

<span class="mw-page-title-main">Timeline of hadrosaur research</span>

This timeline of hadrosaur research is a chronological listing of events in the history of paleontology focused on the hadrosauroids, a group of herbivorous ornithopod dinosaurs popularly known as the duck-billed dinosaurs. Scientific research on hadrosaurs began in the 1850s, when Joseph Leidy described the genera Thespesius and Trachodon based on scrappy fossils discovered in the western United States. Just two years later he published a description of the much better-preserved remains of an animal from New Jersey that he named Hadrosaurus.

<i>Adynomosaurus</i> Extinct genus of dinosaurs

Adynomosaurus is a genus of lambeosaurine dinosaur from the Late Cretaceous of what is now Catalonia, Spain. First discovered in 2012, it was named in 2019 with the type and only species being Adynomosaurus arcanus. It is only known from scant material, but is distinguished from other hadrosaurs by its weakly developed shoulder blade which would have had underdeveloped musculature, which lends it its scientific name, partially from the Greek word for "weak". Its exact relationships with other hadrosaurs remain unresolved, with it not consistently being recovered as a relative of any other specific genera, though some studies have allied it with Tsintaosaurini or even found it outside of Hadrosauridae. It would have lived as part of a diverse coastal estuary ecosystem, made up of meandering rivers and mud flats. The discovery of Adynomosaurus adds to the very incomplete fossil record of hadrosaurid dinosaurs in the Late Cretaceous of Europe, and it fits into a picture of major ecological turnover that was occurring during the Maastrichtian stage in the region.

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.

<i>Oksoko avarsan</i> Extinct species of dinosaur

Oksoko is a genus of oviraptorid dinosaur from the Late Cretaceous of Asia, that lived in what is now the Nemegt Formation in Mongolia. It includes the type species Oksoko avarsan.

<i>Yamatosaurus</i> Genus of hadrosaurid

Yamatosaurus is a genus of basal hadrosaurid from the Late Cretaceous (Maastrichtian)-aged Kita-Ama Formation of Awaji Island, Japan. The genus contains a single species, Yamatosaurus izanagii.

<i>Paralitherizinosaurus</i> Genus of therizinosaurid dinosaurs

Paralitherizinosaurus is an extinct genus of therizinosaurid dinosaur from the Late Cretaceous Osoushinai Formation of Hokkaido, Japan. The genus contains a single species, P. japonicus, known from a partial right hand and cervical vertebra. Paralitherizinosaurus represents the youngest therizinosaur known from Japan.

<span class="mw-page-title-main">Yoshitsugu Kobayashi</span> Japanese paleontologist

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.

References

  1. 1 2 3 4 5 6 7 Kobayashi, Yoshitsugu; Nishimura, Tomohiro; Takasaki, Ryuji; Chiba, Kentaro; Fiorillo, Anthony R.; Tanaka, Kohei; Chinzorig, Tsogtbaatar; Sato, Tamaki; Sakurai, Kazuhiko (September 5, 2019). "A New Hadrosaurine (Dinosauria: Hadrosauridae) from the Marine Deposits of the Late Cretaceous Hakobuchi Formation, Yezo Group, Japan". Scientific Reports. 9 (1): 12389. Bibcode:2019NatSR...912389K. doi: 10.1038/s41598-019-48607-1 . PMC   6728324 . PMID   31488887.
  2. "New hadrosaur from Japan sheds light on dinosaur diversity". phys.org.
  3. 1 2 3 Hokkaido University (September 5, 2019). "A new duck-billed dinosaur, Kamuysaurus japonicus, identified". EurekAlert! . Retrieved September 5, 2019.