Iguanodon
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Iguanodon
mounted in a quadrupedal posture.
Brussels
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Scientific classification
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Iguanodontidae
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Genus:
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Iguanodon
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A formidable weapon: the
Iguanodon'
s thumb.
Iguanodon
skull from the
Oxford University
Museum of Natural History
Skeletal restoration of
I. bernissartensis
by
O.C. Marsh
, 1896
Iguanodon
is a
genus
of
ornithopod
dinosaur
from the
Lower Cretaceous
period in
Europe
,
North America
,
Africa
and
Asia
. It lived 125/126
million
years
ago (mya).
[1]
Discovered in 1822 and described three years later by
English
geologist
Gideon Mantell
,
Iguanodon
was the second dinosaur formally named, after
Megalosaurus
. Together with
Megalosaurus
and
Hylaeosaurus
, it was one of the three genera originally used to define the
Dinosauria
.
A large, bulky
herbivore
,
Iguanodon
is thought by some to be in the same family as the duck-billed
hadrosaurs
. The
taxonomy
of the genus continues to be a topic of study as new species are named or long-standing ones reassigned to other genera.
Scientific understanding of
Iguanodon
has evolved over time. New information is got from the
fossils
. Researchers have made suggestions about the living animal, including feeding, movement, and social behaviour. As one of the first scientifically known dinosaurs,
Iguanodon
is well known.
[2]
There are at least two species recognised:
- I. bernissartensis
, described by
George Albert Boulenger
in 1881, is the
type species
for the genus. This species is best known for the many skeletons discovered in a
coal
mine in
Bernissart
,
Belgium
in 1878. The coal dates to the earliest
Cretaceous
period.
[3]
36 adult skeletons were excavated at this site, a coal mine. This is by far the largest find of this species. The species is large and strong.
- I. galvensis
, described in 2015, is based on adult and juvenile remains found in deposits in
Teruel
, Spain, dating to about 126 mya.
[4]
Because its front limbs were shorter than the hindlimbs, Mantell guessed it could move on two legs, as opposed to
Owen
, who thought it was
quadrupedal
. As it happens, it probably used both modes. Slow walking would be done on all fours, and faster running on the hind legs. Either way, the position of the body would be more horizontal than upright, with the tail held above the ground by its
ossified
(bony)
ligaments
(they can be clearly seen on the skeleton). It would defend itself against predators on its hind legs, using its strong front arms and dagger-like thumbs as weapons.
The teeth were close-set grinding teeth suitable for a
browser
. it is believed that, as with most other
ornithischians
,
Iguanodon
had some sort of
cheek
-like structure, muscular or non-muscular, to keep food in the mouth.
[5]
[6]
- ↑
Norman, David B. 2004. "Basal Iguanodontia". In Weishampel D.B., Dodson P., and Osmolska H. (eds)
The Dinosauria
. 2nd ed, Berkeley: University of California Press. pp413?437
ISBN
0-520-24209-2
- ↑
Norman, David B.; Weishampel, David B. 1990. "Iguanodontidae and related ornithopods". In Weishampel, David B.; Dodson, Peter; and Osmolska, Halszka (eds)
The Dinosauria
. Berkeley: University of California Press. pp510?533
ISBN
0-520-06727-4
- ↑
Paul, Gregory S. 2008. A revised taxonomy of the iguanodont dinosaur genera and species.
Cretaceous Research
29
(2): 192?216.
- ↑
Francisco J. Verdu
et al
2015. Perinates of a new species of Iguanodon (Ornithischia: Ornithopoda) from the lower Barremian of Galve (Teruel, Spain).
Cretaceous Research
56
: 250?264. doi:10.1016/j.cretres.2015.05.010.
- ↑
Galton, Peter M. (1973). "The cheeks of ornithischian dinosaurs".
Lethaia
.
6
(1): 67?89.
doi
:
10.1111/j.1502-3931.1973.tb00873.x
.
- ↑
Fastovsky D.E. and Smith J.B. 2003. Dinosaur paleoecology.
The Dinosauria
, 614?626.