Iguanodon orientalis -Rozhdestvensky, 1952- skull
Archosauria: Ornithischia: Ornithopoda: Iguanodontidae
Locality: Dundgov, Gobi Desert, southwestern Mongolia
Age: Early Cretaceous (Aptian), 120 million years ago
Meaning of name: "tooth of Iguana"
The least varied descendants of the fabrosaurid/hypsilophodontids are the
iguanodontid dinosaurs. They differ from their predecessors
by their larger size and different proportions. The iguanodontids take their family
name from Iguanodon which was one of the first dinosaurs described (in 1825).
They were also the first to be known from an entire skeleton.
First discovered in Europe, skeletons are now known from North America andAsia.
Iguanodon stood erect on two hind legs, with three toes on each foot. Its hands had four
fingers and a spike-like thumb, which it may have used to defend itself. Its teeth are
like of those in hypsilophodonts, flattened across, and leaf-shaped.
They probably sliced up plant material like a pair of scissors.
Iguanodon orientalis is very similar to European iguanodonts except for its large nose.
This hollow structure may have been used as a resonating chamber for making
mating calls. Because of the large number of skeletons frequently
found together, paleontologists think they may have formed herds.
Their fossil skeletons are most often found in sediments deposited in swampy,
lake and river edge environments. This suggests that is the place they spent most of their
time munching on horsetails, ferns, cycads and various kinds of conifers.
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