Phylogeny of iguanodontian dinosaurs and the evolution of quadrupedality Author Poole, Karen E. text Palaeontologia Electronica 2016 a 30 25 3 1 65 http://dx.doi.org/10.26879/702 journal article 10.26879/702 1094-8074 11063310 IGUANODONTIDAE Gervais, 1853 Phylogenetic definition. A stem-based taxon including all taxa more closely related to Iguanodon bernissartensis than to Edmontosaurus regalis . Unambiguous synapomorphies. This clade is characterized by three unambiguous synapomorphies: palpebrals that traverse the entire width of orbit (42.1), postorbital with a bifurcated squamosal process (45.1) small fenestra near the suture of the dentary and surangular lies within the surangular (112.1). (Note that this fenestra is not present in Iguanodon or Equijubus .) Topology. This is another small clade of styracosternans that includes Iguanodon , along with Equijubus , Proa , and Fukuisaurus . As such, the name Iguanodontidae is appropriate, although the taxa included within it are far more closely related to each other than those within the historical conception of Iguanodontidae (e.g., Huxley (1870) included Hypsilophodon and hadrosaurs within Iguanodontidae ). The support for the group is not high, with a jackknife value=12 and a Bremer support of 2, but the same topology is recovered in the Bayesian analysis (with a posterior probability of 0.46).