''Hadrosaurus'' (; ) is a
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
hadrosaurid
Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...
ornithopod dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
s that lived in
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
during the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...
Period in what is now the
Woodbury Formation in
New Jersey
New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
about 83.6 to 77.9 Ma. The
holotype
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...
specimen was found in fluvial marine sedimentation, meaning that the corpse of the animal was transported by a river and washed out to sea. Some fossils are found in the
Tar Heel/Coachman Formation.
They were large animals ranging from and . Most of the preserved elements are very robust, unusual traits in hadrosaurs. ''Hadrosaurus'' were ponderously built animals equipped with
keratin
Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. It is the key structural material making up Scale (anatomy), scales, hair, Nail (anatomy), nails, feathers, horn (anatomy), horns, claws, Hoof, hoove ...
ous beaks for cropping foliage and a specialized and complex dentition for food processing.
''Hadrosaurus foulkii'', the only
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
in this
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
, is known from a single specimen consisting of much of the skeleton and parts of the skull. The specimen was collected in 1858 from the
Woodbury Formation in
New Jersey
New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
, US, representing the first dinosaur species known from more than isolated teeth to be identified in North America. Using
radiometric dating
Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to Chronological dating, date materials such as Rock (geology), rocks or carbon, in which trace radioactive impurity, impurities were selectively incorporat ...
of
bivalve
Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...
shells from the same formation, the sedimentary rocks where the ''Hadrosaurus'' fossil was found have been
dated at some time between 83.6 and 77.9 million years ago. In 1868, the only known specimen became the first-ever dinosaur skeleton to be mounted. In 1991, ''H. foulkii'' became the official
state dinosaur of New Jersey.
History of discovery

In 1838, John Estaugh Hopkins was digging in a
marl
Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae.
M ...
pit (on a small tributary of the
Cooper River in
Haddonfield, New Jersey
Haddonfield is a borough (New Jersey), borough located in Camden County, New Jersey, Camden County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 12,550, an increase of 957 (+8.3%) from the ...
, and part of the
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...
-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
William Parker Foulke (1816–1865) discovered the first full dinosaur skeleton in North America ('' Hadrosaurus foulkii'', which means "Foulke's big lizard") in Haddonfield, New Jersey, in 1858.
Born in Philadelphia, and a descendant of Welsh ...
, 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
A National Historic Landmark (NHL) is a National Register of Historic Places property types, building, district, object, site, or structure that is officially recognized by the Federal government of the United States, United States government f ...
.
Foulke contacted
paleontologist
Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...
Joseph Leidy, and together they recovered eight
teeth
A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...
from the
maxilla
In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...
r and
dentary
In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla).
The jawbone ...
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
A coracoid is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is present as part of the scapula, but this is n ...
, left
humerus
The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...
, left
radius
In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...
, left
ulna
The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...
, left
ilium, right
, right partial
pubis, the left hindlimb composed by the
femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg.
The Femo ...
,
tibia
The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...
,
fibula
The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. ...
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
Greek may refer to:
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group
*Greek language, a branch of the Indo-European language family
**Proto-Greek language, the assumed last common ancestor of all kno ...
, , 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
''Iguanodon'' ( ; meaning 'iguana-tooth'), named in 1825, is a genus of iguanodontian dinosaur. While many species found worldwide have been classified in the genus ''Iguanodon'', dating from the Late Jurassic to Early Cretaceous, Taxonomy (bi ...
'', 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
The American Civil War (April 12, 1861May 26, 1865; also known by Names of the American Civil War, other names) was a civil war in the United States between the Union (American Civil War), Union ("the North") and the Confederate States of A ...
delayed its publication until 1865.
Leidy reconstructed ''Hadrosaurus'' as a biped, in contrast to the view at the time that such dinosaurs were
quadruped
Quadrupedalism is a form of locomotion in which animals have four legs that are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four legs is said to be a quadruped (fr ...
al. The entire skeleton was completely assembled in 1868 by a team including English
sculptor
Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...
and
naturalist
Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...
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, 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
New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...
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 .[Genus List for Holtz 2012]
/ref> 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
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg.
The Femo ...
and tibia
The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...
. Most of the preserved elements feature a marked robust composition with the fibula
The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. ...
being one of the most robust among hadrosaurs.[
]
Classification
Despite the fact that the family Hadrosauridae
Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fam ...
has ''Hadrosaurus'' as its type genus
In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name.
Zoological nomenclature
According to the International Code of Zoological Nomenclature, "The name-bearin ...
, 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
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
.[
''Hadrosaurus'' has also traditionally served as the basis for a large subfamily called Hadrosaurinae, which was seen as a group of largely crestless hadrosaurs related to the crested subfamily Lambeosaurinae. However, the changing view of ''Hadrosaurus'' classification in relation to other hadrosaurs has led some scientists to rename these subfamilies. In a 2008 study, ''Hadrosaurus'' was found to be more primitive than either lambeosaurines or other "hadrosaurines", and not a particularly close relative of classic "hadrosaurines" such as '' Edmontosaurus'' and '' Saurolophus''. As a result of this, the name Hadrosaurinae was restricted to ''Hadrosaurus'' alone, and the subfamily comprising the traditional "hadrosaurines" was renamed the ]Saurolophinae
Saurolophinae is a subfamily (biology), subfamily of hadrosaurid dinosaurs. It has since the mid-20th century generally been called the Hadrosaurinae, a group of largely non-crested hadrosaurs related to the crested sub-family Lambeosaurinae. How ...
.
Below is a simplified cladogram
A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...
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).][
]
Paleobiology
In 2003, Rothschild and colleagues performed a study looking for epidemiology of tumor
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
s in dinosaurs. Evidence of tumors, including hemangiomas, desmoplastic fibroma, metastatic cancer and osteoblastoma
Osteoblastoma is an uncommon osteoid tissue-forming primary neoplasm of the bone.
It has clinical and histologic manifestations similar to those of osteoid osteoma; therefore, some consider the two tumors to be variants of the same disease, wi ...
were discovered in specimens of ''Hadrosaurus'' by analyzing dinosaur vertebrae using computerized tomography
A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...
and fluoroscope screening. Several other hadrosaurids, including '' Brachylophosaurus'', '' Edmontosaurus'' and '' Gilmoreosaurus'', also tested positive. Although more than 10,000 fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
s 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.[ Through the ]radiometric dating
Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to Chronological dating, date materials such as Rock (geology), rocks or carbon, in which trace radioactive impurity, impurities were selectively incorporat ...
of bivalve
Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...
shells known from the formation, the sedimentary rocks where the holotype specimen of ''Hadrosaurus'' was found have been dated from 80.5 million to 78.5 million years ago.[Gallagher, W.B. (2005).]
Recent mosasaur discoveries from New Jersey and Delaware, USA: stratigraphy, taphonomy and implications for mosasaur extinction.
" ''Netherlands Journal of Geosciences'', 84(3): 241. However, a more accurate date make range from 83.6 to around 77.9 mya.
References
External links
The discovery of ''H. foulkii''
Hadrosaurus skeletal diagram
website
Joseph Leidy and ''Hadrodaurus foulkii'' at The Academy of Natural Sciences
''Hadrosaurus foulkii'' exhibit at The Academy of Natural Sciences
{{Taxonbar, from=Q14511
Hadrosauridae
Dinosaur genera
Campanian dinosaurs
Taxa named by Joseph Leidy
Fossil taxa described in 1858
Dinosaurs of the United States