Hadrosaurus

mounted Hadrosaurus, the first mounted dinosaur skeleton in the world In 1838, John Estaugh Hopkins was digging in a marl pit (on a small tributary of the Cooper River in Haddonfield, New Jersey, and part of the Campanian-age Woodbury Formation) when he uncovered large bones. He put them on display at his home, also in Haddonfield. In 1858, the bones sparked the interest of a visitor, William Parker Foulke, who dug out the rest of the bones from the marl pit in the same year. The excavation site, known as the Hadrosaurus foulkii Leidy Site, is now a National Historic Landmark. Foulke contacted paleontologist Joseph Leidy, and together they recovered eight teeth from the maxillar and dentary areas, dental battery fragments, left maxilla fragments, three partial dorsal vertebrae, 13 caudal centra, including an almost complete middle caudal vertebra. Other fragments included a partial right coracoid, left humerus, left radius, left ulna, left ilium, right ischium, right partial pubis, the left hindlimb composed by the femur, tibia, fibula with metatarsals II and IV and the first pedal phalanx from the third digit. Foulke and Leidy studied the fossils together and, in 1858, Leidy formally described and named Hadrosaurus foulkii in honor of his collaborator. While originally a portmanteau of Haddonfield, the location of its discovery with the accepted suffix for dinosaurs -saurus, the name Hadrosaurus was scientifically justified as deriving from the Greek , , meaning "bulky" or "large", and , , meaning "lizard". The name was an additional play on words by Leidy since it translates from Greek as ''Foulke's big lizard''. Leidy recognized that the bones were from a dinosaur because of their similarity to those of Iguanodon, discovered in England some decades before but, at the time, the skeleton of Hadrosaurus was one of the most complete dinosaur skeletons known. Leidy's monograph Cretaceous Reptiles of the United States, describing Hadrosaurus more completely, and with illustrations, was written in 1860, but the American Civil War delayed its publication until 1865. Leidy reconstructed Hadrosaurus as a biped, in contrast to the view at the time that such dinosaurs were quadrupedal. The entire skeleton was completely assembled in 1868 by a team including English sculptor and naturalist Benjamin Waterhouse Hawkins and was put on display at Philadelphia Academy of Natural Sciences. It was the first-ever mounted dinosaur skeleton. When the skeleton was first put together, it was displayed with a plaster skull sculpted by Hawkins. Many other artists have recreated Hadrosaurus with skulls from other, related species such as Gryposaurus and Brachylophosaurus. A statue of Hadrosaurus, sculpted by Haddonfield resident John Giannotti, now stands in the center of the town of Haddonfield along Kings Highway East, commemorating its discovery there. Thanks to Joyce Berry and her fourth-grade classes (1988–1991) at Strawbridge Elementary School in Haddon Township, New Jersey, the Hadrosaurus was named the state dinosaur of New Jersey in 1991. It is one of the most celebrated dinosaurs ever and is of great historic importance. The skeleton is usually kept out of sight in the Academy's collections. However, from November 22, 2008, to April 19, 2009, a fully assembled cast of the skeleton, and an exhibit about the science and culture surrounding the dinosaur's discovery, was open to the public. ==Description==

Hadrosaurus were large-sized animals growing up to and weighing as much as . According to Prieto-Márquez, Hadrosaurus can be distinguished in having a shortened pectoral crest that is slightly over 40% of the total humeral length, a deltopectoral crest that is developed from the humeral shaft causing the laterodistal border to display a broad lateral facet, a lower greatest point of the supraacetabular crest located above lateral edge from the rear to the bottom on the posterior tuberosity of the ischial peduncle of the ilium, a shortened supraacetabular crest from the front to the rear with its breadth being half the length of the middle iliac plate. As in most hadrosaurs, the forelimbs were not as heavily built as the hindlimbs, but were long enough to be used in standing or movement. The holotype specimen was a relatively large animal at the time of death with a femur and tibia. Most of the preserved elements feature a marked robust composition with the fibula being one of the most robust among hadrosaurs. ==Classification==

Despite the fact that the family Hadrosauridae has Hadrosaurus as its type genus, the skeleton lacks a skull and was long viewed as too incomplete to compare to other hadrosaurs for classification purposes, leading most scientists to consider it a nomen dubium, or dubious name. Below is a simplified cladogram recovered by Ramírez-Velasco et al. in 2012 in their description of Huehuecanauhtlus. This topology was recovered using an extensive sampling of 60 hadrosauroid species, and two outgroup taxa, which were scored based on 287 morphological traits, and included data from two recent redescriptions of Hadrosaurus by Prieto-Márquez et al. (2006) and Prieto-Márquez (2011). Academy of Natural Sciences }} ==Paleobiology==

In 2003, Rothschild and colleagues performed a study looking for epidemiology of tumors in dinosaurs. Evidence of tumors, including hemangiomas, desmoplastic fibroma, metastatic cancer and osteoblastoma were discovered in specimens of Hadrosaurus by analyzing dinosaur vertebrae using computerized tomography and fluoroscope screening. Several other hadrosaurids, including Brachylophosaurus, Edmontosaurus and Gilmoreosaurus, also tested positive. Although more than 10,000 fossils were examined in this manner, the tumors were limited to Hadrosaurus and other hadrosaurs. The tumors were only found on caudal vertebrae and they may have been caused by environmental factors or genetic inheritance. ==Paleoecology==

The holotype of Hadrosaurus was found in marine sediments, which suggests the skeleton was transported by a river and then deposited in the Cretaceous sea. The Hadrosaurus remains all persist to the Woodbury Formation. However, a more accurate date make range from 83.6 to around 77.9 mya. ==References==