Micropachycephalosaurus

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Ordo: †Ornithischia
Cladus: †Genasauria
Cladus: †Neornithischia
Cladus: †Cerapoda
Cladus: †Marginocephalia
Subordo: †Pachycephalosauria

Familia: †Pachycephalosauridae
Genus: Micropachycephalosaurus
Species: M. hongtuyanensis
Name

Micropachycephalosaurus Dong
Vernacular names
čeština: Micropachycephalosaurus

Micropachycephalosaurus (meaning "small thick-headed lizard") was a monotypic genus of ceratopsian dinosaur. It lived in China during the Late Cretaceous period.[1] The skeleton of the single specimen, IVPP V5542 was found on a cliff southwest of Laiyang, Shandong Province in the Jiangjunding Formation. It was a bipedal and herbivorous dinosaur.[2]

Taxonomy

The genus contains only the type species, Micropachycephalosaurus hongtuyanensis. Paleontologist Dong Zhiming originally described it as a member of the Pachycephalosauria, a group of bipedal dome-headed herbivores.

However, re-evaluation of the family Pachycephalosauridae by Sullivan in 2006 cast doubt on this assignment.[3]

Further study of the original specimens by Butler and Zhao in 2008 also failed to find any characteristics linking Micropachycephalosaurus with the pachycephalosaurs. The one piece of evidence that could provide this link, the supposedly thickened skull roof, was missing from the fossil collection the scientists examined, and so could not be used to support or refute its original classification. Butler and Zhao therefore classified it as an indeterminate member of the Cerapoda.[2]

In 2011, cladistic analysis performed by Butler et al. showed that Micropachycephalosaurus is a basal member of the Ceratopsia.[4]

Micropachycephalosaurus has the longest name of any dinosaur, with 23 letters.[5]
See also

Dinosaurs portal

Timeline of ceratopsian research
Timeline of pachycephalosaur research

References

Holtz, Thomas R. Jr. (2011) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2010 Appendix.
Butler, R.J. & Zhao, Q. (2009). "The small-bodied ornithischian dinosaurs Micropachycephalosaurus hongtuyanensis and Wannanosaurus yansiensis from the Late Cretaceous of China". Cretaceous Research. 30 (1): 63–77. doi:10.1016/j.cretres.2008.03.002.
Sullivan, R.M. (2006). "A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia)." New Mexico Museum of Natural History and Science Bulletin, 35: 347-365.
Richard J. Butler; Jin Liyong; Chen Jun; Pascal Godefroit (2011). "The postcranial osteology and phylogenetic position of the small ornithischian dinosaur Changchunsaurus parvus from the Quantou Formation (Cretaceous: Aptian–Cenomanian) of Jilin Province, north-eastern China". Palaeontology. 55 (3): 667–683. doi:10.1111/j.1475-4983.2011.01046.x.
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