Lanzhousaurus

Lanzhousaurus Temporal range: Early 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 that lived in the Gansu region of what is now China during the Early Cretaceous (Barremian). Described by You, Ji, and Li in 2005, the type and only species is Lanzhousaurus magnidens, known from a partial skeleton recovered from the Hekou Group. ^[1] It has been estimated to be about 10 meters (33 ft) in length and 6 metric tons (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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