''Shantungosaurus'' (meaning "''Shandong Lizard''") is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of very large

saurolophine Saurolophinae is a subfamily of hadrosaurid dinosaurs. It has since the mid-20th century generally been called the Hadrosaurinae, a group of largely non-crested hadrosaurs related to the crested sub-family Lambeosaurinae. However, the name Had ...

hadrosaurid Hadrosaurids (), or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod family, which incl ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

found in the Late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

Wangshi Group of the Shandong Peninsula in China, containing a single species, ''Shantungosaurus giganteus''. The

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers ( strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostr ...

interval of ''Shantungosaurus'' ranges from the top of the Xingezhuang Formation to the middle of the Hongtuya Formation, middle to late

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

in age. ''Shantungosaurus'' is so far the largest hadrosauroid taxon in the world, reaching between to in length and to in body mass.

History of discovery

First described in 1973, ''Shantungosaurus'' is known from over five incomplete skeletons. Chinese scientist Xing Xu and his colleagues indicate that ''Shantungosaurus'' is very similar to and shares many unique characters with ''

Edmontosaurus ''Edmontosaurus'' ( ) (meaning "lizard from Edmonton") 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 ro ...

'', forming a node of an ''

''–''Shantungosaurus'' clade between North America and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...

, based on the new materials recovered in Shandong. Remains of several individuals, including skull bones, limb bones, and

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...

e, were found in Shandong, China. These specimens were classified in the new genus and species ''Zhuchengosaurus maximus'' in 2007. However, further study showed that the supposedly distinct features of ''Zhuchengosaurus'' were simply a result of different growth stages.Ji, Y., Wang, X., Liu, Y., and Ji, Q. (2011). "Systematics, behavior and living environment of ''Shantungosaurus giganteus'' (Dinosauria: Hadrosauridae)." ''Acta Geologica Sinica (English Edition)'', 85(1): 58-65.

Description

''Shantungosaurus giganteus'' is one of the largest known

ornithischia Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek ...

ns. The

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

skull is long, and the composite skeleton mounted at the

Chinese Academy of Geological Sciences The Chinese Academy of Geological Sciences (CAGS; ) is an institution that engages in geoscience research in the People's Republic of China. The academy was established in 1956 and reorganized in 1999. Administratively it is under the PRC Ministr ...

Beijing } Beijing ( ; ; ), alternatively romanized as Peking ( ), is the capital of the People's Republic of China. It is the center of power and development of the country. Beijing is the world's most populous national capital city, with over 21 ...

measures in length. Another mounted skeleton, originally referred to as ''Zhuchengosaurus maximus'', measures in length. The largest individuals may have weighed as much as . In 2016, Gregory S. Paul suggested that previous studies have overestimated the size of this dinosaur, moderating it at in length and in body mass, which still makes this dinosaur the largest hadrosaur. Like all hadrosaurs its beak was toothless, but its jaws were packed with around 1,500 tiny chewing teeth. A large hole near its

nostril A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called t ...

s may have been covered by a loose flap of skin, which could be inflated to make sounds.

Classification

Recent maximum parsimony-based

phylogenetic analyses In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

of Hadrosauroidea from Xing and colleagues recovered a stable sister group relationship between ''

'' and ''Shantungosaurus''. ''Shantungosaurus'' is the single hadrosaurid from the Zhucheng area that is considered valid. ''Zhuchengosaurus'' and ''Huaxiaosaurus'', both of which are known from the same region, have been interpreted by the analyses as junior synonyms of ''Shantungosaurus''. All unequivocal morphological discrepancies among these three taxa could be attributed to intraspecific variation (ontogenetic and polymorphic variation) and post-depositional distortion. The following

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

is the result of Prieto-Márquez ''et al.'' in 2016. It shows the position of ''Shantungosaurus'' as

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

of ''Edmontosaurus'' in the Edmontosaurini clade:

References

Sources

* * {{Taxonbar, from=Q131158 Late Cretaceous dinosaurs of Asia Saurolophines Monotypic dinosaur genera Fossil taxa described in 1973 Ornithischian genera

History of discovery

Description

Classification

See also

References

Sources