Dyoplosaurus

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Dyoplosaurus
Temporal range: Late Cretaceous, 76.5Ma
Dyoplosaurus.tif
Holotype skull
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Family: Ankylosauridae
Subfamily: Ankylosaurinae
Genus: Dyoplosaurus
Parks, 1924
Species: † D. acutosquameus
Binomial name
Dyoplosaurus acutosquameus
Parks, 1924

Dyoplosaurus (meaning "double-armored lizard") is an extinct genus of ankylosaurid dinosaurs within the subfamily Ankylosaurinae. It is known from the lower levels of the Late Cretaceous Dinosaur Park Formation (latest middle Campanian stage, about 76.5 Ma ago) of Alberta, Canada. It contains a single species, Dyoplosaurus acutosquameus.[1]

Description[edit]

Tail of the holotype specimen

The type specimen of Dyoplosaurus was fifteen feet (four to five meters) long and about 5.8 feet (1.7 m) wide, with a skull measuring 14 inches (35 centimeters) across. Like most other ankylosaurids, it was quadrupedal, ground-dwelling and herbivorous, with an armored body and a bony club on the end of its tail. The club was composed of several armor plates fused together.[2] The tail club possessed by Dyoplosaurus is relatively small and narrow, when compared to that of other ankylosaurids.

History of discovery[edit]

Dyoplosaurus was named by William Parks in 1924, based on holotype ROM 784, a partial skeleton including parts of the skull and lower jaws. It was collected from the bottom 10 m of the Dinosaur Park Formation, near what is now the Red Deer River in Alberta, Canada.

Classification[edit]

Reconstructed tail and pelvis

In 1971, Walter Coombs proposed that Dyoplosaurus was a junior synonym of Euoplocephalus. The two were since generally assumed to be the same species and thus, former Dyoplosaurus specimens have been identified as Euoplocephalus tutus. However, a recent redescription of the genus published in 2009 in the Journal of Vertebrate Paleontology claims that the genus is a valid taxon, suggesting that the proposed synonymy was due to the fragmentary nature of the holotype and other specimens of E. tutus.[1] The cladistic analysis performed by Thompson et al., 2011 confirmed this separation.[3]

Model

The following cladogram is based on the phylogenetic analysis of the Ankylosaurinae conducted by Arbour and Currie (2013):[4]

Ankylosaurinae

Scolosaurus (=Oohkotokia horneri)





Ankylosaurus




Anodontosaurus



Euoplocephalus







Dyoplosaurus



Talarurus



Tsagantegia





Minotaurasaurus



Nodocephalosaurus



Tianzhenosaurus





Pinacosaurus grangeri



Pinacosaurus mephistocephalus





Tarchia



Saichania










References[edit]

  1. ^ a b Arbour, V. M.; Burns, M. E.; Sissons, R. L. (2009). "A redescription of the ankylosaurid dinosaur Dyoplosaurus acutosquameus Parks, 1924 (Ornithischia: Ankylosauria) and a revision of the genus". Journal of Vertebrate Paleontology 29 (4): 1117. doi:10.1671/039.029.0405.  edit
  2. ^ Parks, W. A. (1924). "Dyoplosaurus acutosquameus, a new genus and species of armored dinosaur; and notes on a skeleton of Prosaurolophus maximus". University of Toronto Studies Geological Series 18: 1–35. 
  3. ^ Richard S. Thompson, Jolyon C. Parish, Susannah C. R. Maidment and Paul M. Barrett (2011). "Phylogeny of the ankylosaurian dinosaurs (Ornithischia: Thyreophora)". Journal of Systematic Palaeontology. in press. doi:10.1080/14772019.2011.569091. 
  4. ^ Arbour V.M. and Currie P.J., 2013, "Euoplocephalus tutus and the Diversity of Ankylosaurid Dinosaurs in the Late Cretaceous of Alberta, Canada, and Montana, USA", PLoS ONE 8(5): e62421. doi:10.1371/journal.pone.0062421

External links[edit]