Hadrosaurus

Abstract: Hadrosaurus foulkii was the first dinosaur known outside Europe from partially complete skeletal elements It is the holotype of the family Hadrosauridae and the subfamily Hadrosaurinae The history of its discovery and taxonomy is re− viewed, and the holotype of H foulkii is redescribed The holotype of H foulkii lacks distinguishing characters; therefore, this taxon is a nomen dubium It is not synonymous with species of Gryposaurus and/or Kritosaurus We also reevaluate the taxonomy and osteology of H tripos, H minor, H cavatus, H breviceps, H paucidens, and Ornithotarsus immanis In agreement with previous studies, these taxa are considered nomina dubia due to the absence of distinguishing charac− ters and are therefore referrable only to Hadrosauridae indeterminate; H paucidens is referrable to Lambeosaurinae inde− terminate Finally, our phylogenetic analysis indicates that the holotype of H foulkii belongs to a member of Euhadro− sauria and, tentatively, of Hadrosaurinae

Abstract: The cranial and postcranial anatomy of the basal hadrosaurid dinosaur Eotrachodon orientalis, from the uppermost Santonian of southern Appalachia (southeastern U.S.A.), is described in detail. This animal is the only known pre-Campanian non-lambeosaurine hadrosaurid, and the most complete hadrosauroid known from Appalachia. E. orientalis possesses a mosaic of plesiomorphic and derived characters in the context of Hadrosauroidea. Characters shared with basal hadrosauroids include a short and sloping maxillary ectopterygoid shelf, caudally prominent maxillary jugal process, one functional tooth per alveolus on the maxillary occlusal plane, a jugal rostral process with a shallow caudodorsal margin and medioventrally facing articular facet, a vertical dentary coronoid process with a poorly expanded apex, and tooth crowns with accessory ridges. Derived characters shared with other hadrosaurids include a circumnarial depression compartmented into three fossae (as in brachylophosaurins and Edmontosaurus), a thin everted premaxillary oral margin (as in Gryposaurus, Prosaurolophus, and Saurolophus), and a maxilla with a deep and rostrocaudally extensive rostrodorsal region with a steeply sloping premaxillary margin (as in Gryposaurus). Eotrachodon orientalis differs primarily from the other hadrosauroid from the Mooreville Chalk of Alabama, Lophorhothon atopus, in having a slender and crestless nasal whose caudodorsal margin is not invaded by the circumnarial depression. Hadrosaurus foulkii, the only other known hadrosaurid from Appalachia, is distinct from E. orientalis in having dentary teeth lacking accessory ridges and a dorsally curved shaft of the ischium. A histological section of the tibia of the E. orientalis holotype (MSC 7949) suggests that this individual was actively growing at the time of death and, thus, had the potential to become a larger animal later in development.

Abstract: The authors of this study describe such East Coast dinosaurs as: Astrodon johnstoni, which browsed in a tropical Maryland some 100 million years ago; Anchisaurus polyzelus, which lived in New England around 200 million years ago; and Hadrosaurus foulkii, a dick-billed dinosaur that lived in New Jersey 70 million years ago, and which was North America's first well-preserved dinosaur skeleton. The text shows how dinosaur finds have come from both the bog iron and clay pits of Maryland and New Jersey, and the river banks of North and South Carolina in addition, dinosaur footprints have been found from central Virginia to the Bay of Fundy in Nova Scotia.

Abstract: Hadrosauridae constitutes a very diverse clade of herbivorous dinosaurs that were extremely abundant during the Campanian–Maastrichtian (Late Cretaceous) of Europe, Asia, both Americas, and probably also Antarctica (Horner et al . 2004). The fact that hadrosaurids are one of the best-known clades of dinosaurs, represented by arguably the richest dinosaurian fossil record, contrasts with the scarcity of material and apparently undiagnostic nature of their type genus and species, Hadrosaurus foulkii . The holotype and only known specimen of H. foulkii is also historically significant for being the first skeletal remains of a dinosaur described outside Europe (Leidy 1858).