Ankylopollexia is a clade of herbivorous iguanodontian dinosaurs that lived from the Late Jurassic to Late Cretaceous in all continents. Some members include Camptosaurus, Iguanodon, Ouranosaurus, and the hadrosaurids or "duck-billed dinosaurs". The Ankylopollexia was named by Paul Sereno in 1986 to denote the group within the Iguanodontia that includes the Camptosauridae and the Styracosterna. The name means "stiff thumbs", referring to a possible synapomorphy, possessing a conical thumb spine. Ankylopollexians were generally large animals, and some (such as Shantungosaurus, which measured up to 50 ft (15 m) in length and weighed up to 8 tons) equaled the largest carnivorous dinosaurs in size.
The first definition of Ankylopollexia was given by Sereno in 1998. It was defined as the node-based taxon consisting of the last common ancestor of Camptosaurus, Parasaurolophus and all his descendants. Sereno (2005) improved this definition, using the type species, Camptosaurus dispar (Marsh 1879) and Parasaurolophus walkeri (Parks 1922), instead of the genera. Many ankylopollexians have not yet been included in a large phylogenetic analyses, or are too fragmentary to place confidently. These include Bihariosaurus, Delapparentia, Dollodon, Draconyx, Hypselospinus, Lurdusaurus, Osmakasaurus, Owenodon, Planicoxa, Proplanicoxa and Sellacoxa. The simplified cladogram below follows an analysis by Andrew McDonald and colleagues, published in November 2010 with information from McDonald, 2011.
The cladogram below follows an analysis by Andrew McDonald, 2012.
- ^ Sereno, P.C. (1986). "Phylogeny of the bird-hipped dinosaurs (order Ornithischia)". National Geographic Research 2 (2): 234–56.
- ^ a b Carpenter, K. and Ishida, Y. (2010). "Early and "Middle" Cretaceous Iguanodonts in Time and Space". Journal of Iberian Geology 36 (2): 145–164. doi:10.5209/rev_JIGE.2010.v36.n2.3.
- ^ McDonald, A.T.; Kirkland, J.I.; DeBlieux, D.D.; Madsen, S.K.; Cavin, J.; Milner, A.R.C.; Panzarin, L. (2010). "New Basal Iguanodontians from the Cedar Mountain Formation of Utah and the Evolution of Thumb-Spiked Dinosaurs". In Farke, Andrew Allen. PLoS ONE 5 (11): e14075. doi:10.1371/journal.pone.0014075. PMC 2989904. PMID 21124919.
- ^ Andrew T. McDonald (2011). "The taxonomy of species assigned to Camptosaurus (Dinosauria: Ornithopoda)". Zootaxa 2783: 52–68.
- ^ McDonald, A. T. (2012). "Phylogeny of Basal Iguanodonts (Dinosauria: Ornithischia): An Update". In Farke, Andrew A. PLoS ONE 7 (5): e36745. doi:10.1371/journal.pone.0036745. PMC 3358318. PMID 22629328.