Hadrosaurus foulkii

Hadrosaurus foulkii, a genus of hadrosaurid ornithopod dinosaurs that lived in North America during the Late Cretaceous Period, approximately 83.6 to 77.9 million years ago, is notable for being the first relatively complete dinosaur skeleton discovered in North America; the holotype specimen was unearthed in 1858 in Haddonfield, New Jersey, by William Parker Foulke, who excavated the bones from a marl pit on the farm of Joseph Hopkins, where large bones had been found as early as 1838; this significant find was later analyzed by paleontologist Joseph Leidy, who named the species Hadrosaurus foulkii in honor of Foulke; the discovery site, now known as the Hadrosaurus foulkii Leidy Site, has been designated a National Historic Landmark and is recognized as the location where the first relatively complete dinosaur skeleton was found in the United States; Hadrosaurus was a large, herbivorous dinosaur, estimated to have grown up to 7 to 8 meters in length and weighing as much as 3.2 tons; it was equipped with keratinous beaks for cropping foliage and possessed a specialized and complex dentition for food processing, which included dental batteries composed of tightly packed teeth that were continually replaced, allowing it to efficiently grind plant material; the forelimbs of Hadrosaurus were not as heavily built as the hindlimbs but were long enough to be used in standing or movement, suggesting that it was a facultative biped, capable of walking on both two and four legs; the holotype specimen, which was a relatively large animal at the time of death, had a femur measuring 1.05 meters and a tibia measuring 93.3 centimeters, with most of the preserved elements featuring a marked robust composition, including a notably robust fibula; the discovery of Hadrosaurus foulkii was groundbreaking, as it was the first dinosaur species known from more than isolated teeth to be identified in North America, providing significant insight into the anatomy and posture of dinosaurs; in 1868, the only known specimen became the first-ever dinosaur skeleton to be mounted, which was displayed at the Academy of Natural Sciences in Philadelphia, bringing the find to a wider public audience and marking a milestone in the field of paleontology; this mounted display was significant not only for being the first of its kind but also because it presented Hadrosaurus in a bipedal posture, contrasting with the prevailing view at the time that such dinosaurs were quadrupedal; the genus name Hadrosaurus is derived from the Greek words “hadros,” meaning “bulky” or “large,” and “sauros,” meaning “lizard,” reflecting its considerable size; the species name “foulkii” honors William Parker Foulke, who played a crucial role in its discovery; the holotype specimen was found in fluvial marine sedimentation, indicating that the corpse of the animal was transported by a river and washed out to sea, which is consistent with the depositional environment of the Woodbury Formation in New Jersey, where the fossil was discovered; radiometric dating of bivalve shells from the same formation has dated the sedimentary rocks where the Hadrosaurus fossil was found to between 83.6 and 77.9 million years ago; Hadrosaurus is classified within the family Hadrosauridae, commonly known as duck-billed dinosaurs due to the flat, duck-bill appearance of the bones in their snouts; this family is divided into two principal subfamilies: the lambeosaurines, which had hollow cranial crests or tubes, and the saurolophines, which lacked hollow cranial crests; Hadrosaurus is considered to be more primitive than either lambeosaurines or other “hadrosaurines” and is not a particularly close relative of classic “hadrosaurines” such as Edmontosaurus and Saurolophus; 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; however, a re-evaluation of the fossil material in 2011 noted several distinct characteristics of the skeleton that could allow the genus Hadrosaurus and species H. foulkii to remain in use as valid taxa; the discovery of Hadrosaurus foulkii not only provided significant insight into the anatomy and posture of dinosaurs but also marked a turning point in the field of paleontology, as it was the first relatively complete dinosaur skeleton found in North America and the first to be mounted for public display, thereby enhancing public interest and understanding of dinosaurs; in recognition of its significance, H. foulkii was designated the official state dinosaur of New Jersey in 1991; today, a statue of Hadrosaurus, sculpted by Haddonfield resident John Giannotti, stands in the center of the town of Haddonfield, commemorating its discovery there and serving as a reminder of the important role this dinosaur played in the history of paleontology.