HADROSAUROIDEA, 1986

Poole, Karen E., 2016, Phylogeny of iguanodontian dinosaurs and the evolution of quadrupedality, Palaeontologia Electronica (a 30) 25 (3), pp. 1-65 : 20

HADROSAUROIDEA Sereno, 1986

Phylogenetic definition. The most inclusive taxon containing Parasaurolophus walkeri Parks, 1922 but not Iguanodon bernissartensis Boulenger, 1881 ( Sereno, 2005).

Unambiguous synapomorphies. Hadrosauroids are characterized largely by features related to the “dental battery”, which become even more exaggerated in the hadrosaurids. The clade has 18 unambiguous synapomorphies: antorbital fenestra absent (29.1), left and right squamosals separated by only a narrow band of the parietal (73.1), long diastema of the dentary, the width of three or more teeth (93.1), dentary, rostral extent of Meckel's groove meets the dentary symphysis: absent, ends more caudally (94.1), caudal extent of dentary tooth row is in line with or caudal to the apex of the coronoid process (103.2), coronoid process of the dentary oriented near vertically (105.1), coronoid process of the dentary with a rostrocaudally expanded apex (107.1), maxillary teeth with a primary ridge only (136.0), dentary tooth row with one functional tooth rostrally and caudally, and up to two teeth at and approaching the middle of the dental battery (150.1), maximum of two replacement dentary teeth (151.1), dentary without discrete alveoli, but parallel grooves lining a continuous dental battery (152.1), most proximal chevron placed at distal end of third caudal vertebra or more distally (186.2), coracoid, length of the scapular articulation less than 1.25 times the length of the lateral margin of the glenoid (207.1), radius length greater than 70% of humeral length (220.1), metacarpal III long and slender, length greater than 5.5 times the transverse width at mid-shaft (230.1), preacetabular process of the ilium is parallel-sided or slightly tapering at its distal end (251.0), base of the preacetabular process of the ilium is not transversely thickened ventrally (252.0), ischium shaft straight in lateral view (281.0), distal condyles of femur with rounded articular surfaces (305.1).

Topology. Support in the parsimony tree is low (jackknife=7, Bremer support=2), but there is strong support in the Bayesian tree (posterior probability=0.96). It includes Probactrosaurus , Batyrosaurus , Altirhinus , Jeyawati , Eolambia , Protohadros , Shuangmiaosaurus , Levnesovia , Gilmoreosaurus , Bactrosaurus , Tethyshadros , Telmatosaurus , Edmontosaurus , Maiasaura , and Hypacrosaurus . This topology agrees with the results of other recent studies (e.g., Gates and Scheetz, 2014; Prieto-Márquez, 2012).