Lanzhousaurus

{{automatic taxobox

| fossil_range = Lower Cretaceous, {{Fossil range|130}}

| image = Skeleton of Lanzhousaurus magnidens.jpg

| image_caption = Skeletal mount of Lanzhousaurus

| taxon = Lanzhousaurus

| authority = You, Ji & Li, 2005

| type_species = {{extinct}}Lanzhousaurus magnidens

| type_species_authority = You, Ji & Li, 2005

}}

Lanzhousaurus (meaning "Lanzhou lizard") is a genus of ornithopod dinosaur. Lanzhousaurus lived in the Gansu region of what is now China during the Early Cretaceous (Barremian). A partial skeleton has been recovered from the Hekou Group. It was described by You, Ji and Li in 2005 and the type and only species is Lanzhousaurus magnidens.{{Cite journal |last1=You |first1=Hailu |last2=Ji |first2=Qiang |last3=Li |first3=Daqing |year=2005 |title=Lanzhousaurus magnidens gen. et sp. nov. from Gansu Province, China: the largest-toothed herbivorous dinosaur in the world |trans-title=中国甘肃发现世界上最大牙齿的植食性恐龙：巨齿兰州龙(新属、新种) |url=https://www.researchgate.net/publication/294696068 |journal=Geological Bulletin of China |language=en |volume=24 |issue=9 |pages=785–794 |issn=1671-2552}} It has been estimated to be about 10 meters (33 feet) in length and 6 tonnes (6.6 short tons) in weight.{{Cite book|title=The Princeton Field Guide to Dinosaurs (2nd ed.)|last=Paul|first=Gregory S.|publisher=Princeton University Press|year=2016|location=New Jersey|pages=319}}

Dentition

File:Lanzhousaurus (jaw and teeth).png

The genus has been described as having "astonishingly huge teeth", among the largest for any herbivorous creature ever, which indicate it was a styracosternan iguanodont. The mandible, longer than one meter, suggests a very large size for the animal. Tooth enamel 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). doi:10.1038/s41598-017-15653-6

Classification

File:Lanzhousaurus UDL.png]]

In their 2020 reassessment of the hadrosauromorph Orthomerus, Madzia, Jagt & Mulder ran phylogenetic analyses of Iguanodontia. In their analyses, Lanzhousaurus was recovered as a non-hadrosauriform styracosternan member of the Ankylopollexia, similar to the 2005 description by You, Ji & Li. The results of their phylogenetic analyses are shown in the cladogram below:{{Cite journal |last1=Madzia |first1=Daniel |last2=Jagt |first2=John W. M. |last3=Mulder |first3=Eric W. A. |date=2020-04-01 |title=Osteology, phylogenetic affinities and taxonomic status of the enigmatic late Maastrichtian ornithopod taxon Orthomerus dolloi (Dinosauria, Ornithischia) |journal=Cretaceous Research |volume=108 |pages=104334 |doi=10.1016/j.cretres.2019.104334 |issn=0195-6671|doi-access=free |bibcode=2020CrRes.10804334M }}