Pachyrhinosaurini

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Pachyrhinosaurins
Temporal range: Late Cretaceous, 84.9–69 Ma
Pachyrhinosaurus.jpg
Skull of a Pachyrhinosaurus canadensis
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Family: Ceratopsidae
Subfamily: Centrosaurinae
Clade: Eucentrosaura
Tribe: Pachyrhinosaurini
Fiorillo & Tykoski, 2012
Type species
Pachyrhinosaurus canadensis
Sternberg, 1950
Subdivisions[1]

Pachyrhinosaurini was a tribe of centrosaurine dinosaurs. The clade existed during the Late Cretaceous, about 84.9 to 66 million years ago, evolving during the earliest Campanian,[2] and becoming extinct in the Maastrichtian.[3][4] The tribe contains three genera: Einiosaurus, Achelousaurus, and Pachyrhinosaurus. Pachyrhinosaurus and Achelousaurus form the clade of pachyrhinosaurins called the Pachyrostra ("thick-snouts"), characterized primarily by their nasal bosses.

Classification[edit]

Pachyrhinosaurini was defined in 2012 by Fiorillo & Tykoski. It was defined as all centrosaurine ceratopsids more closely related to Pachyrhinosaurus canadensis than to Centrosaurus apertus. It was defined during the description of Pachyrhinosaurus perotorum, a species from Alaska.[3]

The cladogram below represents the findings of Lund et al., 2016, in their description of Machairoceratops cronusi. Wendiceratops pinhornensis, Xenoceratops foremostensis, and Sinoceratops zhuchengensis were resolved as members of the Pachyrhinosaurini and Einiosaurus was resolved as a pachyrostran and the sister taxon of Achelousaurus.

Ceratopsidae 

Chasmosaurinae


 Centrosaurinae 


Machairoceratops cronusi





Albertaceratops nesmoi



Diabloceratops eatoni





Avaceratops lammersi



Nasutoceratops titusi






 Centrosaurini 


Rubeosaurus ovatus



Styracosaurus albertensis





Spinops sternbergorum




Centrosaurus apertus



Coronosaurus brinkmani





 Pachyrhinosaurini 


Xenoceratops foremostensis



Sinoceratops zhuchengensis





Wendiceratops pinhornensis


 Pachyrostra 


Einiosaurus procurvicornis



Achelousaurus horneri





Pachyrhinosaurus canadensis




Pachyrhinosaurus lakustai



Pachyrhinosaurus perotorum











The cladogram below represents a more recent phylogenetic analysis that included Pachyrhinosaurini by Chiba et al. (2017). Wendiceratops, Xenoceratops, and Sinoceratops were not resolved as members of the Pachyrhinosaurini and Einiosaurus was not resolved as a pachyrostran.[5]

Centrosaurinae


Diabloceratops eatoni



Machairoceratops cronusi




Nasutoceratopsini

Avaceratops lammersi (ANSP 15800)



MOR 692



CMN 8804



Nasutoceratops titusi



Malta new taxon





Xenoceratops foremostensis





Sinoceratops zhuchengensis



Wendiceratops pinhornensis




Albertaceratops nesmoi



Medusaceratops lokii


Eucentrosaura
Centrosaurini


Rubeosaurus ovatus



Styracosaurus albertensis





Coronosaurus brinkmani




Centrosaurus apertus



Spinops sternbergorum





Pachyrhinosaurini

Einiosaurus procurvicornis


Pachyrostra

Achelousaurus horneri




Pachyrhinosaurus canadensis




Pachyrhinosaurus lakustai



Pachyrhinosaurus perotorum











See also[edit]

References[edit]

  1. ^ Sampson, S.D.; Lund, E.K.; Loewen, M.A.; Farke, A.A.; Clayton, K.E. (2013). "A remarkable short-snouted horned dinosaur from the Late Cretaceous (late Campanian) of southern Laramidia". Proceedings of the Royal Society B. 1766. 280: 4. doi:10.1098/rspb.2013.1186. PMC 3730592Freely accessible. PMID 23864598. 
  2. ^ Gilmore, C.W. (1930). "On dinosaurian reptiles from the Two Medicine Formation of Montana". Proceedings of the United States National Museum. 77 (16): 1–39. doi:10.5479/si.00963801.77-2839.1. 
  3. ^ a b Fiorillo, A.R. & Tykoski, R.S. (2012). "A new Maastrichtian species of the centrosaurine ceratopsid Pachyrhinosaurus from the North Slope of Alaska". Acta Palaeontologica Polonica. 57 (3): 561. doi:10.4202/app.2011.0033. 
  4. ^ Fiorillo, A.R. & Gangloff, R.A. (2001). "Theropod teeth from the Prince Creek Formation (Cretaceous) of northern Alaska, with speculations on Arctic dinosaur paleoecology". Journal of Vertebrate Paleontology. 20 (4): 675–682. doi:10.1671/0272-4634(2000)020[0675:TTFTPC]2.0.CO;2. 
  5. ^ Kentaro Chiba; Michael J. Ryan; Federico Fanti; Mark A. Loewen; David C. Evans (2018). "New material and systematic re-evaluation of Medusaceratops lokii (Dinosauria, Ceratopsidae) from the Judith River Formation (Campanian, Montana)". Journal of Paleontology. in press. doi:10.1017/jpa.2017.62.