Lanzhousaurus

Lanzhousaurus Temporal range: Lower Cretaceous, 130  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Skeletal mount of Lanzhousaurus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Dinosauria
Clade:	† Ornithischia
Clade:	† Ornithopoda
Clade:	† Styracosterna
Genus:	† Lanzhousaurus You, Ji & Li, 2005
Type species
†Lanzhousaurus magnidens 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. ^[1] It has been estimated to be about 10 meters (33 feet) in length and 6 tonnes (6.6 short tons) in weight. ^[2]

Dentition

Jaw and teeth of Lanzhousaurus

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. ^[3]

Classification

Life restoration

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: ^{[4] [1]}

Ankylopollexia	Camptosaurus Styracosterna Cumnoria Uteodon Draconyx Planicoxa Theiophytalia Hippodraco Owenodon Muttaburrasaurus Dakotadon Osmakasaurus Cedrorestes Iguanacolossus Lanzhousaurus Yunganglong Fukuisaurus Hadrosauriformes Siamodon Hypselospinus Barilium Lurdusaurus Iguanodontidae Hadrosauroidea

References

1. You, Hailu; Ji, Qiang; Li, Daqing (2005). "Lanzhousaurus magnidens gen. et sp. nov. from Gansu Province, China: the largest-toothed herbivorous dinosaur in the world" [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)]. Geological Bulletin of China. 24 (9): 785–794. ISSN   1671-2552.
2. Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs (2nd ed.). New Jersey: Princeton University Press. p. 319.
3. 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 Reports7, Article number: 15319 (2017). doi:10.1038/s41598-017-15653-6
4. Madzia, Daniel; Jagt, John W. M.; Mulder, Eric W. A. (2020-04-01). "Osteology, phylogenetic affinities and taxonomic status of the enigmatic late Maastrichtian ornithopod taxon Orthomerus dolloi (Dinosauria, Ornithischia)". Cretaceous Research . 108 104334. Bibcode:2020CrRes.10804334M. doi: 10.1016/j.cretres.2019.104334 . ISSN   0195-6671.

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