THE ORNITHOPODAN DINOSAURS
Anatosaurus was the classic "duck-billed"
dinosaur. It had a low skull, without a crest, and a broad snout
area like a duck's beak. It was a large animal, up to 43ft. (13m)
long. Anatosaurus is known by many skeletons, and some
have been "mummified" so that parts of the skin have
been preserved. There were several species of Anatosaurus
that lived right through to the end of the Cretaceous period.
Short . crested reptile
Brachylophosaurus was one of the most primitive duck-billed
dinosaurs, or hadrosaurs. It had a simple crest made from the
nasal bones. These ran back between the eyes to form a broad
plate. There was a little spike pointing backward. The crest was
solid in Brachylopshosaurus, and its exact purpose is hard to
determine. It may have been an identification. It may have been
an identification signal to let other dinosaurs known what kind
of dinosaur it was.
Late Jurassic and early Creataceous
Wastern Europe and western USA
Camptosaurus was heavily built up to 23ft (7m) long.
It was similar in many respects to iguanodon, Camtosaurus had
long powerful hindlegs and much shorter arms. However, it had
small hooves on each finger of the heand, which shows that it
walked on all fours at least some of the time. About ten spicies
of Comptosaurus have been decribed from fiffrent pats of Europe
and North America. These all differ by size and proportion, but
it shows how widespread this dinosaur was.
Claosaurus was noe of the earliest duck-billed
dinosaurs. The duck bills, such as corythosaurus, parasaurolophus
and tsintaosaurus, often had fancy crets on top of their heads.
Claosaurus hardly had any crest. It was alsoprimitive in features
of its legs and feet. Its slim body was only 12ft. (3.5m) or so
Corythosaurus is one of the best known of the
hadrosaurs (duck-billed dinosaurs). It was a large animal
over 33ft (10m) lnog. The crest on top of the head was high and
narrow from side to side. It was from the nostrils on the snout
up into the crest and then down again into the mouth.
Corythosaurus may have used this complicated breathing-tube
system to make loud bellows and honks. There are several species
of Corythosaurus which are based on the shape of the crest. The
closest relative of Corythosaurus was lambeosaurus.
Late JurassicWestern USA, Tanzania
Dryosaurs was a relative of hypsilophodon, but much
larger: Dryosaurus was 10-13ft. (3-4m) long. It had powerful
legs, and strong arms, each with five fingers. Dryousaurus could
have run fast on its hing legs. Its tail was stiff and it could
have been used for balance. Dryosaurus probably used its hand to
gather plants to eat. Its back teeth were sharp and ridget, but
the teeth at the front of the jaw were not. Dryosaurus is known
from several skletons and skulls from africa and Nort
America,which proves that these two parts of the world were
joined 140million yearc ago. Dryosaurs lived with the well known
ssauropods apatosarus, brachiosaurus and diplodocus, the
stegosaurs stegosaurus and kentrosaurus and the meat-eaters
allosaurus, coelurus and elaphrosaurus.
Alberta, Canadan and Montana USA
Edmontosaurus was a duck-billed dinosaur with a flat
head, rather like anatosaurus and shantungosaurus. Edmontosaurus
is quite weŔŔ known because several skeletons havee been found.
It was one of the largest duck-billed, 43ft (13m) long. The skull
was low in front and high in back. There was a wide duck-like
beak (as in Antatosaurus) Edmontosaurus had about a thousand
strong teeth, and probably fed ao tough plants which neede to be
Late Triassic/ early Jurassic
Lesotho, South Africa
Fabrosaurus was an early primitive ornithopod related
to scutellosaurus. It was only 40in (1m) long and would not have
been able look over a dinner table if it had stood upas straight
it could. Fabrosaurus was very lightly built and ran on its hind
legs. It had strong arms and hands: The teeth were strong, with
frilled or knobbly edges. This shows that Fabrosaurus could use
its teeth to chop up vegetation.
Late Triassic/early Jurassic
Geranosaurus was a small ornithopos that was closly
related to hieterodontosaurus and lycorhinus. It is only known
from parts of its jaws and a few other bones. The jawsshow that
it had sharp teeth at the front of the jaw , a pair of fangs
behind, and ridged cheek teeth at the back. The front teeth were
used to snip off pieces of plants.
New Jersey and New Mexcico, USA, And Alberta, Canada
Hadrosaurus was the first dinosaur to be named from
North America. A skeleton without a skull was collected from new
Jersey and duck-billed shape, like anatosaurus and edmontosaurus.
There was a rounded hump in front of the eyes and above the
Different toothed reptile
Late Triassic/early Jurassic
Heterodontosaurus is the best-known early ornithopod.
Seven diffrent hetrodontosaurids have been named from southern
Africa, Argentina amd China, but these are mostly based on
discoveries of jaw pieces. Hetrodontosaurus is known from a good
skull and skeleton. It had three diffrent kinds of teeth: sharp
cutting teeth at the front, fangs , and broad, ridged cheek teeth.
This kind of arrangment is unusual far a dinosaur. Most dinosaurs
had only one kind of tooth. Humans have three kinds, just like
Heterodontsarus. Heterodontosaurus was about 4ft (1.2m) long, and
it was an active animal that could run on it hind legs.
Very high-ridged reptile
Alberta, Canada, and Montana, USA
Hypacrosaurus was a large duck-billed dinosaur, about
30ft (9m) long. It was an advanced form, elated to corythosaurus
and lambeosaurus. Hypacrosaurus had a short, high skull and its
crest was rounded, but lower and fatter than that of
Corythosaurus. The crest pointed backward into a solid bony spike.
Hypacrosaurus had dozens of strong teeth which formed a large
area for grinding and chopping tough vegetation. As the teeth
wore down they were replaced by new ones.
Hypsilophodon is an interesting medium-sized
ornithopod. It was 7.5 (2.3m) long. It had short arms, each with
five fingers, and long legs, each with four toes. Hypsilophodon
could run fast, and it had a long stiff tail, which it used for
balance. It was once thought that Hypsilophodon climbed trees,
but this is not likely since it could not grasp the branches.
Hypsilophodon had no teeth at the front of its mouth, but only a
bony źbeak╗, and a row of sharp chopping teeth further back. It
could have nipped plants off with its beak, and chopped them up
with its check teeth.
Western Europe, Nort Africa
Iguanodon was the second dinosaur to be named
in 1925 Iguanodon was up to 30ft (9m) long and stood 16.5ft (5m)
high. Iguanodon had strong hind limbs with three big toes, each
with a hooklike nail. The hand and a spikelike thum, which was
probably used as a weapon. The tail was flattend and stiff, and
Iguanodon could have run well on its hind legs or walked on all
fours. There were n oteeth at the front of the jaw only a
bony beak like that of hypsilophodon. The cheek teeth were strong
and ridged. Iguanodon may have pulled plants into its mouth with
its tongue, and nipped them off with its beak.
Lambes's (Canadia paleontologist) reptile
Alberta, Canada, and Montana, USA
Lambeosaurus was a crested duck-billed dinosaur
related to corythosaurus and hypacrosaurus. Lambeosaurus had a
square-shaped crest that ponted forward and a long spine that
pointed backward. The nostrils in the snout continued down
through the crest, making a large hollow cavity. In some
specimens of Lambeosaurus the crest was bigger than the skull.
Lambeosaurus was big about 50ft (15m) long and its
Late Triassic/early Jurassic
Lyxorhinus is an important, but very poorly known,
dinosaur. It was one of the early orithopods. a
heterodontosaurid and its close relatives are geranosaurus
and heterodontosaurus. Lycorhinus was named in 1942 from part of
the left jaw of a very small dinosaur. It shows a large tusk, and
teeth as in Heterodontosaurus.
Maiasaura is one of the most important dinosaur found
recently. In 1978 and 1979, skeletons of adult Maiasaura were
found with nests and babies. The mother was about 30ft. (9m)
long, and the young animal only 40in (1m) long. The nests were
made in mounds which were only 40in (1m) long. The nest were made
in mounds which were 10ft (3m) across, and the eggs were arranged
in several layers. In each layer the eggs, which were shaped lake
sauseges , lay in circles like the spikes of a wheel. The mother
Maiasaura clearly laid her eggs so that they were all kept warm
until the young ones hatched out. However, the young animals that
have been found were not hatchlings, so they were staying around
the nest as they grew up. This has been indicated that these
dinosaurs looked after their young.
Muttaburra (where found reptile)
Muttaburrasaurus is one of the very few dinosaurs
known from Australia. It is a recent find and was named in1981.
Muttaburrasaurus was 23ft. (7m) long and it was related to
iguanodon or to camptosaurus. It had low, broad head, and it has
been suggested that its teeth could have been used for chewing
plants or meat. Earlier Australian dinosaurs show close
simlarities with African and American ones , but by the late
Cretaceous periodm Australia may have had its own particular
animals. Like most late Cretaceous ornithopods Muttaburrasaurus
was larger than its early Jrassic counterparts.
Named after Othniel C. Marsh,
Othnelia was a small dinosaur, only 4.5ft (1,4m) long.
It was very similar to hypsilophodon, but there were small
differences in the teeth. It was orihinally named Nanosaurus by
Othniel C. Marsh in 1877, and was renamed in 1977.
Niger, West Africa
Ouranosaurus in one of the most interesting dinosaurs
from Norh Africa. It was related to iguanodon, but had a tall
sail down its back. The sail was supported by a fence of spines
on the backbone on on each vertebra. The sail was made of
skin, and blood vessels must have flowed through it. It may have
been used by Ouranosaurus to keep its body temperature constant.
If it was too hot, it could lose heat through the sail, and if it
was too cold, it could take in heat from the sun. Another
dinosaur with a sail was the meat-eater spinosaurus.
Reptile with parallel-sided crest
Alberta, Canada, Utah and New Mexcico, USA
Parasaurolophus was one of the most bizzare duck-billed
dinosaur. It had a long tubular crest that curved back from its
snout for a distance of up to 6ft (1,8m). The nostrils were in
their normal place at the front of the snout, and the breathing
tubes ran right up the crest and back down again into the mouth.
If you cut the crest open, you would find four tubes two
going up and two coming down. The crest may have been a signal to
let another Parasaurolophus recognize a member of its own species.
Also if Parasaurolophus breathed out strongly, it could have made
a honk or bellow inside the crest.
Parks's (Canadian palaeontologist) reptile
Parksosaurus was one of the last surviving
hypsilophodontids. Its earlier relatives include dryosaurus,
hypsilophodon and zephyrosaurus. Parksosaurus is known from an
incomplete skeleton. When this animal died, it was buried on its
left side in the sand, and most of the other side of the skeleton
was broken up and lost. Parksosaurus had large eyes and a
relatively short thigbone. Parksosaurus was about 8ft (2,5m) long.
Prosaurolophus was a large duck-billed dinosaur, up to 26ft.
(8m) long. The skull was low and had a small crest which ran up
from the tip of the snout. There was a small knob at the top of
this. Prosaurolophus is supposed to have been a relative of
saurolophus, which lived about five million years later.
North America and Asia
Saurolophus was an advanced, duck-billed, crested
dinosaur about 33ft. (10m) long. It is known from several
skeletons. The animal had a large head with a pointed crest
runnig backward. The snout was broad, and the top of the head
sloped backward as a flat surface. The skull bones above eyes
continued backward as a spike which stuck out behind the head.
There were two species of Saurolophus: the North American
and Asian. They were very similar, except the fact that the Asian
one had longer skull and crest.
Little shield reptile
Scutellosaurus is an interesting early ornithopod that
was named in 1981. Scutellosaurus had a short skull with
ridged teeth for eating plants. Its hind legs were longer than
the arms, but by a smaller amount than in most ornithopods. Scutellosaurus
had a very long tail about one-and-a-half times its
total length of 4ft (1.2m). Scutellosaurus was armored
with hundreds of small bony knobs set in the skin of its back.
This kind of armor as not been found in its relatives, such as
Secernosaurus is one of the few duck.billed dinosaurus
known from South America. Most duck bills lived in North America
and Asiam and this South American duck-bill shows that there was
a land connection which dinosaurs could cross. Secernosaurus
probably had a flat head like edmontosaurus or shantungosaurus.
The skeleton, named in 1979, shows that Secernosaurus was
a small duck-bill, probably only 10ft (3m) long.
Shantung (where found) reptile
Shantungosaurus was an advanced, duck-billed dinosaur
with a flat head. It was the largest of this group, being over 40ft.
(12m) long. Shantungosaurus had a long, low skull, with a
flat, duck-shaped beak and no crest. A nearly complete skeleton
of Shantungosaurus was discovered in the 1970s. A grown
man standing beside it just reaches its knee.
Alberta, Canada, and Montana, USA
Tro÷don is a poorly known but very unusual animal. A
pointed saw-edged tooth named Tro÷don in 1856, and in the
1940s more fossils seemed to show that it was the same as the
bone-head stegoceras. Discoveries in 1979 and 1980 show that Tro÷don
may have been related to hypsilophodon and parksosaurus. However,
its teeth were sharp and like those of a heat-eater. If Tro÷don
did eat meat, it would be the only ornithischian dinosaur to do
Reptile from Tsintao
Tsintaosaurus was a very strange duck-billed dinosaur.
It had a tall horn on the top of its head, just between the eyes.
The horn pointed forward and was hollow. The breathing tubes ran
up the horn. Tsintaosaurus was large about 33ft. (10m)
long. It may be related to saurolophus or to parasaurolophus.
Zephyrosaurus was rather like hypsilophodon, and is
one of the few dinosaurs whose name begins with the letter Z.
It was named in 1980 from a skull and a few vertebrae. Zephyrosaurus
had small ridged teeth which were adapted for efficient chewing
of plants. Zephyrosaurus was a two-legged animal, about 6ft.