''Lanzhousaurus'' (meaning "

Lanzhou Lanzhou (, ; ) is the capital and largest city of Gansu Province in Northwest China. Located on the banks of the Yellow River, it is a key regional transportation hub, connecting areas further west by rail to the eastern half of the country. H ...

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 nom ...

ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous w ...

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 ...

. ''Lanzhousaurus'' lived in the

Gansu Gansu (, ; alternately romanized as Kansu) is a province in Northwest China. Its capital and largest city is Lanzhou, in the southeast part of the province. The seventh-largest administrative district by area at , Gansu lies between the Tibe ...

region of what is now

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

during the Early

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 ...

(

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded ...

). A partial

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

has been recovered from the

Hekou Group The Hekou Group is a geological group in Gansu Province, China. It is Early Cretaceous in age. Dinosaur body fossils have also been recovered from the Hekou Group, including the iguanodont '' Lanzhousaurus'' and the titanosaurs ''Daxiatitan'', ' ...

. It was described by You, Ji and Li in

2005 File:2005 Events Collage V2.png, From top left, clockwise: Hurricane Katrina in the Gulf of Mexico; the Funeral of Pope John Paul II is held in Vatican City; " Me at the zoo", the first video ever to be uploaded to YouTube; Eris was discover ...

and the type and only species is ''Lanzhousaurus magnidens''.You, H.-L. (2005) ''Lanzhousaurus magnidens'' from the Lower Cretraceous of Gansu province, China: The largest-toothed herbivorous dinosaur in the world. ''JVP'' 26(3) Abstracts pp. 142 It's been estimated to be about 10 meters (33 feet) in length and 6 tonnes (6.6 short tons) in weight.

Dentition

The genus has been described as having "astonishingly huge teeth", among the largest for any

herbivorous 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 mouthpar ...

creature ever, which indicate it was a

styracosterna Ankylopollexia is an extinct clade of ornithischian dinosaurs that lived from the Late Jurassic to the Late Cretaceous. It is a derived clade of iguanodontian ornithopods and contains the subgroup Styracosterna. The name stems from the Greek wor ...

iguanodont Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include ''Camptosaurus'', ''Dryosaurus'', ''Iguanodon'', '' Tenontosaurus'', and the hadrosaurids or "duck-bil ...

. The

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

, longer than one meter, suggests a very large size for the animal.

Tooth enamel Tooth enamel is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, ...

of this dinosaur was growing very rapidly. Celina A. Suarez, Hai-Lu You, Marina B. Suarez, Da-Qing Li & J. B. Trieschmann (2017). Stable Isotopes Reveal Rapid Enamel Elongation (Amelogenesis) Rates for the Early Cretaceous Iguanodontian Dinosaur ''Lanzhousaurus magnidens''. ''Scientific Reports'' 7, Article number: 15319 (2017). do
10.1038/s41598-017-15653-6
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References

Early Cretaceous dinosaurs of Asia Fossil taxa described in 2005 Iguanodonts Paleontology in Gansu Ornithischian genera {{ornithopod-stub