''Arstanosaurus'' (meaning "Arstan lizard" after the Arstan well) is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of hadrosauroid

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

from the

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...

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. Campa ...

-age

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cret ...

Bostobe Formation,

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

. It has had a confusing history, being considered both a hadrosaurid and a

ceratopsid Ceratopsidae (sometimes spelled Ceratopidae) is a family of ceratopsian dinosaurs including ''Triceratops'', '' Centrosaurus'', and '' Styracosaurus''. All known species were quadrupedal herbivores from the Upper Cretaceous. All but one species are ...

, or both at the same time ( chimeric).

History

The genus was based on a partial left

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

(

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

AAIZ 1/1 or IZ AN KSSR 1/1), with the lower end of a left

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

(AAIZ 1/2) possibly referable. Both were found at Akkurgan-Boltyk near Qyzylorda and were named and described as ''Arstanosaurus akkurganensis'' in 1982.Shilin, F.V., and Suslov, Y.V. (1982). A hadrosaur from the northeastern Aral Region. ''Paleontological Journal'' 1982(1):132-136 ranslated version This is not much material for naming a new genus, and it was largely ignored until the mid-1990s, when the hypothesis that it was really a ceratopsid appeared.Nesov, L.A. (1995). ''Dinozavri severnoi Yevrasii: Novye dannye o sostave kompleksov, ekologii i paleobiogeografii'' 'Dinosaurs of Northern Eurasia: new data about assemblages, ecology and paleobiogeography'' ''Scientific Research Institute of the Earth's Crust''. St. Petersburg State University:St. Petersburg, Russia, 156 pp. + 14 pl. ussian Shortly thereafter, a new revision appeared that showed that the characteristics listed as unusual for ''Arstanosaurus'' were really based on perspective, and that the maxilla was from an animal like '' Bactrosaurus'', albeit indeterminate (a dubious name). The femur was uninformative.Norman, D.B., and Kurzanov, S.M. (1982). On Asian ornithopods (Dinosauria: Ornithischia). 2. ''Arstanaosaurus akkurganensis'' Shilin and Suslov, 1982. ''Proceedings of Geologists' Association'' 108(3):191-199. It was regarded as an indeterminate hadrosaurid in the most recent review.Horner, J.R., Weishampel, D.B., and Forster, C.A. (2004). Hadrosauridae. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). ''The Dinosauria'' (second edition). University of California Press:Berkeley, 438-463. . Diagnostic hadrosauroid remains from the same area have in 2012 been named as '' Batyrosaurus''. A hadrosauroid from the Bayan Shireh Formation (informally called " Gadolosaurus") has at times been identified as ''Arstanosaurus'', but is clearly a distinct genus.Tsogtbaatar, K., D. Weishampel, D. C. Evans, and M. Watabe. (In review). A New Hadrosauroid (Dinosauria: Ornithopoda) from the Late Cretaceous Baynshire Formation of the Gobi Desert (Mongolia). PLOS ONE

Paleobiology

As a hadrosaurid, ''Arstanosaurus'' would have been a

biped Bipedalism is a form of terrestrial locomotion where an animal moves by means of its two rear (or lower) limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' ' ...

al/

quadrupedal Quadrupedalism is a form of Animal locomotion, locomotion in which animals have four legs that are used to weight-bearing, bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four l ...

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

, eating plants with sets of ever-replacing teeth stacked on each other.

References

{{Taxonbar, from=Q2697199 Hadrosauroidea Dinosaur genera Santonian dinosaurs Campanian dinosaurs Fossil taxa described in 1982 Dinosaurs of Asia

History

Paleobiology

See also

References