DRYOSAURIDAE Milner and Norman, 1984

Poole, Karen E., 2016, Phylogeny of iguanodontian dinosaurs and the evolution of quadrupedality, Palaeontologia Electronica (a 30) 25 (3), pp. 1-65 : 18

DRYOSAURIDAE Milner and Norman, 1984

Phylogenetic definition. The most inclusive clade containing Dryosaurus altus ( Marsh, 1878) but not Parasaurolophus walkeri Parks, 1922 ( Sereno, 2005).

Unambiguous synapomorphies. Dryosauridae is characterized by nine unambiguous synapomorphies: premaxilla with a medial dorsal (nasal) process that does not contact the nasal (9.1), palpebrals that traverse the entire width of orbit (42.1), a dentary with dorsal and ventral margins (under the tooth row) that converge anteriorly (97.0), maxillary teeth with primary ridges that are centered mesio-distally (143.0), 15 or fewer dorsal vertebrae (161.0), posterior dorsal vertebrae with transverse processes longer than the dorsoventral height of the centrum (167.1), scapula with a weakly developed acromion process (195.0), prepubic process with a horizontal ridge on medial side (273.1) and a pubis with an obturator foramen completely enclosed by bone (275.0)

Topology. In addition to Dryosaurus and Dysalotosaurus , which have been found previously to form a clade ( McDonald et al., 2010b), this analysis finds the unnamed Kirkwood taxon from South Africa within the group, as sister to Dysalotosaurus . The clade is well supported, with a jackknife value of 60, and Bremer support of 4. In the Bayesian topology, Dryosauridae also contains Valdosaurus as sister to the Kirkwood taxon (PP=0.27).