Hai Xing; Deyou Wang; Fenglu Han; Corwin Sullivan; Qingyu Ma; Yiming He; David W. E. Hone; Ronghao Yan; Fuming Du; Xing Xu

“ Hadrosauroidea is the least inclusive taxon containing Equijubus normani and Parasaurolophus walkeri, which follows the phylogenetic topology argued by You et al. [1] . This clade has a series of unambiguous synapomorphies, including the elongate anteroventral corner of the lacrimal, the elevated, subrectangular jugal sutural surface of the maxilla that closely abuts the lacrimal sutural surface of the bone, and the moderately expanded transversely oral margin of the rostrum that is greater than 1.5 times as wide as the maximum constriction of the snout. ”

“ Furthermore, the phylogenetic analysis carried out as part of the study could provide new insights into the evolutionary relationships among derived basal hadrosauroids and hadrosaurids, and helps to test the potential dispersal patterns that have been previously suggested for basal hadrosauroids. Attention is also paid to the statistical partitions of osteological measurements; the dataset of each measurement attribute is the collection of the corresponding values for most species within Hadrosauroidea and several close relatives of this group. ”

“ The nutrient foramina are limited to the dorsal half of the maxilla. The number of nutrient foramina is consistent with that of maxillary tooth positions. The dental battery of the maxilla includes a minimum of 27 tooth positions. As preserved, the occlusal surface is dorsally convex because of the downward curvature of the posterior third of the maxilla, and is also inclined to face ventromedially. ”

“ Except for the wide arcuate laterodistal corner of the deltopectoral crest, the vast majority of the features in H. foulkii are typical of Edmontosaurus and Shantungosaurus (see Supporting Information S4) . Prieto-Márquez [63] discussed the wide arcuate laterodistal corner of the deltopectoral crest seen in H. foulkii and basal hadrosauroids, and considered it to be plesiomorphic for Hadrosauroidea, in comparison with the angular laterodistal corner of the deltopectoral crest common among most hadrosaurids. ”

“ Although the Majiacun Formation extends in age from the late Coniacian through to the end of the Santonian, the dinosaur-bearing bed very likely dates to the middle Santonian [28] , [30] . In addition to the hadrosauroid material, the formation has yielded dinosaur eggs, a spinosaurid tooth, the incomplete articulated postcranial skeleton of an alvarezsaurid, a partially preserved sacrum belonging to an ankylosaurid, sauropod cervical vertebrae, turtle shell elements, and crocodilian dorsal vertebrae [28] , [30] , [31] . ”

“ The condition is nearly identical to that of some basal hadrosauroids and most lambeosaurines, but differs from all hadrosaurines, in which a prominent deltoid ridge gradually broadens posteroventrally, and is continuous anterodorsally with the acromion process [2] . Proximally, the scapular neck is strongly constricted dorsoventrally. The dorsoventral depth of this constriction is about 50% of the maximum dorsoventral height of the proximal region of the scapula. The scapular blade is mediolaterally compressed and subrectangular in shape. ”

“ Southwestern Henan Province in central China contains many down-faulted basins, including the Xixia Basin where the Upper Cretaceous continental sediments are well exposed. The Majiacun Formation is a major dinosaur-bearing stratigraphic unit that occurs in this basin. ”

“ The strongly concave parapophysis has migrated dorsally to the dorsolateral side of the neural arch, and is located just below the base of the transverse process. The elongate transverse processes, which no longer bear the prezygapophyses medially, extend posterodorsally and laterally from the neural arch. ”

“ For the tree topology of Hadrosaurinae in the strict consensus, our present analysis does not significantly alter the relevant result argued by Xing et al. [56] . There is one exception to the condition: Lophorothon atopus is placed as the sister group to the clade composed of the genera Prosaurolophus and Saurolophus (Fig. 13) , based on the anatomical data of the holotype of this species [62] . The posterior fragments of the paired nasals are well preserved in the holotype of L. atopus. ”

“ The vertebra also has some osteological features that are common for the dorsal series, such as the large, dorsomedially-facing articular facet of the prezygapophysis that is entirely higher than and located dorsolateral to the neural canal in anterior view, the gently concave parapophysis on the anterolateral side of the base of the neural arch, and the slightly shorter anteroposteriorly centrum (Fig. 7A, C) . In anterior view, the centrum of D1 is about 1.6 times as tall as the paired neural arches ”

“ When these four characters are coded as polymorphic for Brachylophosaurus, Shantungosaurus, and Edmontosaurus, the alternate phylogeny indicates that H. foulkii is definitely a member of the monophyletic group that consists of all non-lambeosaurine hadrosaurids (Fig. 15; Supporting Information S5, Fig. 3) . Therefore, H. foulkii is considered here a nomen dubium owing to a lack of diagnostic characters, and may represent an enigmatic member of the monophyletic group that consists of all non-lambeosaurine hadrosaurids (i.e. Hadrosaurinae) . ”

“ Prieto-Márquez [2] used MCA, as implemented in the package Mclust of the statistical program R, to divide each of three morphology-based datasets into several discrete intervals with an optimal number of clusters. After this clustering, the intervals of the one-dimensional dataset were objectively transformed into independent but associated character states used for phylogenetic analysis [2] . ”

“ Yu, T-X & Lauters, P (2008) , New hadrosaurid dinosaurs from the uppermost Cretaceous of northeastern China, vol. 53, pp. 47–74 ↑ Prieto-Márquez, A; Chiappe, LM & Joshi, SH (2012) , The Lambeosaurine Dinosaur Magnapaulia laticaudus from the Late Cretaceous of Baja California, Northwestern Mexico, vol. 7 (6) , p. e38207, 22719869, pmid:22719869, DOI 10.1371/journal.pone.0038207 1 2 Prieto-Márquez, A; Weishampel, DB & Horner, JR (2006) , The hadrosaurid dinosaur Hadrosaurus foulkii from the Campanian of the East coast of North America, with a review of the genus, vol. ”