''Arstanosaurus'' (meaning "Arstan lizard" after the
Arstan well) is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
hadrosauroid
Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and all dinosaurs more closely related to them than to ''Iguanodon''. Their remains have been recovered in Asia, Eu ...
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 ...
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 mya. The ...
-
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. Campanian s ...
-age
Upper Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', the ...
Bostobe Formation
The Bostobe Formation ( kk, Boztóbe svıtasy) is a geological formation in Qaraghandy & Qyzylorda, Kazakhastan whose strata date back to the Late Cretaceous (Santonian to early Campanian stages, approximately 85 Ma).
The sandstones and claystones ...
,
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
. 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 k ...
, or both at the same time (
chimeric).
History
The genus was based on a partial left
maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates 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 t ...
(
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...
AAIZ 1/1 or IZ AN KSSR 1/1), with the lower end of a left
femur
The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...
(AAIZ 1/2) possibly referable. Both were found at
Akkurgan-Boltyk near
Qyzylorda
Kyzylorda ( kk, Қызылорда, translit=Qyzylorda, ), formerly known as Kzyl-Orda (russian: Кзыл-Орда), Ak-Mechet (Ак-Мечеть), Perovsk (Перовск), and Fort-Perovsky (Форт-Перовский), is a city in south-cen ...
.
[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
''Bactrosaurus'' (; meaning "Club lizard," "baktron" = club + ''sauros'' = lizard) is a genus of herbivorous hadrosauroid dinosaur that lived in Asia during the Late Cretaceous, about 96-85 million years ago. The position ''Bactrosaurus'' occupie ...
'', 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
Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and all dinosaurs more closely related to them than to ''Iguanodon''. Their remains have been recovered in Asia, Eu ...
remains from the same area have in 2012 been named as ''
Batyrosaurus
''Batyrosaurus'' is an extinct genus of herbivorous basal hadrosauroid dinosaur known from the Late Cretaceous Bostobe Formation (Santonian to Campanian stage) of central Kazakhstan. It contains a single species, ''Batyrosaurus rozhdestvenskyi'' ...
''.
A hadrosauroid from the
Bayan Shireh Formation
The Bayan Shireh Formation (also known as Baynshiree/Baynshire, Baynshirenskaya Svita or Baysheen Shireh) is a geological formation in Mongolia, that dates to the Cretaceous period. It was first described and established by Vasiliev et al. 1959. ...
(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 organism moves by means of its two rear 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'' 'double' a ...
al/
quadrupedal
Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...
herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
, eating plants with sets of ever-replacing teeth stacked on each other.
[
]
See also
* Timeline of hadrosaur research
A timeline is a display of a list of events in chronological order. It is typically a graphic design showing a long bar labelled with dates paralleling it, and usually contemporaneous events.
Timelines can use any suitable scale representin ...
References
{{Taxonbar, from=Q2697199
Late Cretaceous dinosaurs of Asia
Hadrosaurs
Fossil taxa described in 1982
Ornithischian genera