Reptiles
of the Past
There are many ways to study reptiles of the past.
But as we are geared for children you will find our views are not
like many other museums. We are not a collection of bones, we are
a way of looking at things. We are about fun and edutainment and
the wonder of a child's mind.
All dinosaurs are reptiles...
But all reptiles were not dinosaurs.
Click
on the stamp to read about the dinosaur
Ceratosaurus
This medium sized
carnivore measured around 20 feet long and weighed up to 1,200 pounds.
We do not know its exact range but fossils or indications seem to
place it in the Colorado, Wyoming, and Utah area during the Jurassic
at 150 million years or so ago.
What is unusual
about this dinosaur is that it had a distinctive horn and two bony
ridges on its skull that gave it a very fierce appearance. Its name
means "Horned reptile." We do not know the exact reason for these
horns, but it is somewhat likely that they served as displays to
impress the females and possibly acquire either a "harem" or better
breading rights through prime territories or some such much like
Elk do today. In the same unusual vein this ancient reptile also
was the only meat eater to have some armor. The exact function of
the smallish armored bumps is unknown and again may have been due
to a selection process of the females of the species who may have
simply "liked it."
Another unusual
feature is that unlike the T rex with two fingers or the Allosaurus
with three fingers the Ceratosaurus had four fingers. They do not
appear to be strong enough for grasping or tearing so they likely
had the same function that those of the T rex did.
The teeth were
very sharp and the structure of the jaws tells us this species likely
sliced off large sections of its victim and possibly let them bleed
to death before feeding.
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Camptosaurus
This early member
of the iguanodontids has only one recognized species from North
America, Camptosaurus dispar. It reached lengths over 20 feet and
maybe weighed up to 1 1/4 tons. Later relatives included the Iquanodon's
and Hadrosaur's.
It is highly likely
that this late Jurassic plant eater was a favorite prey of the carnivores
like Allosaurus. It's name means "bent lizard" which is referring
to the fact that the large thigh bone in the leg is curved in order
to keep its legs further apart so that they could clear the wide
rib cage. This dinosaur because of its anatomy and lifestyle probably
spent most of its life walking on two legs. Its shape was rather
bottom heavy but because of this the Camptosaurus was likely fairly
maneuverable.
The teeth were
much like grinders and likely preferred leafy vegetation which must
have been retained in the cheek pouches until it was well chewed.
They have often been found in the vicinity of Stegosaur and Camarasaur
fossils so likely did not compete for food with them but liked the
more sparsely available vegetation in this type of habitat so as
not to compete with the much larger sauropods.
Camarasaurus
A close relative
of the brachiosaurs and titanosaurs, this late Jurassic dinosaur
was apparently quite common in North America and some areas of Europe
and Africa. Never as big as its closest relatives this dinosaur
was 50 to 60 feet in length and weighed 30 or 40 tons. Its name
means "chambered lizard" which is referring to the hollowed chambers
found in the vertebrae, most likely to cut down on weight.
This sauropod was
very heavily built and its head looked a bit like a cross between
a bulldog and a horse. Its teeth were very unique in that they looked
like ivory spoons and this dinosaur was obviously adapted to eating
hard and fibrous plant materials. It likely bit off large portions
of trees and bushes and swallowed them hole. The stomach was adapted
to grinding up these large bites with the aid of stones. One prominent
paleontologist commented that the Camarasaurus should be likened
to an elephant but with its head on the end of its trunk and its
teeth in its stomach.
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Brachiosaurus
One of the largest
of all the sauropods was the Brachiosaurus. Who can forget that
moment in Jurassic park when they first saw these magnificent creatures
walk out of the water and stand up to browse from the top of a tall
tree. The name means "arm lizard" which refers to the fact that
its front legs or "arms" were longer than the rear legs. In size
we find a true giant with lengths to 30 feet and weights of up to
80 ton with heads as tall as 50 feet above the ground.
Like many other
large sauropods wherever weight could be saved it was. The head
of brachiosaurs were very light weight and had many hollow areas
throughout. This creature when full grow would have no competition
for food and it is unlikely any carnivore or even a pack of carnivores
would not even try and tackle this formidable plant eater.
The species were
undoubtedly restricted to areas where tall trees grew in profusion.
Fossil recorders from North America are scarce and no complete skeleton
has ever been recovered. It is likely that its range was restricted
to riverine areas of Utah and Colorado. A slightly more slender
species has been found in some numbers in Africa.
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Goniopholis
A late Jurassic
reptile closely related to the dinosaurs with relatives still living
today is the Goniopholis which means "angled scutes." This ancient
crocodilian looked very much like many of the crocs found today.
Many people think
only that various dinosaurs populate the Mesozoic, but this actually
a great distortion. As far as numbers and species count most of
the know ancient world was likely to be very much like today in
terms of turtles, tortoises, frogs, lizards, crocodilians, and their
prey which consisted of insects, salamanders, and even small dinosaurs.
The big boys of the dinosaurian persuasion were truly awesome and
terrifying, but they were a very small part of the total picture
ecological.
Ancient crocodiles
have been around as long as the dinosaurs and from their first beginnings
about 235 million years ago as long legged running archosaurs they
have evolved out into a myriad of forms.
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Stegosaurus
A Middle Jurassic to
late Cretaceous dinosaur that almost everyone knows is the Stegosaurus
who's name means "roof lizard" in mention of its plates running down
its back that actually grew right out of its skin. In size we find
a 20 to 30 foot length with body size similar to present day rhino's.
What a
traumatic but fascinating scene in Walt Disney's Fantasia scene
where the Stegesaurs gets killed to dramatic music by a Rex. Like
its close relatives the ankylsaurs, this was a veritable tank when
it came to defense. The plates on it's back likely served the function
of both heating & cooling as well as protection. They were apparently
covered only with skin and many blood vessels rather than the horny
protection originally thought. Around its throat were a network
of bony studs. And its sideways pointing spikes that were over 3
1/2 feet long served as a powerful deterrent to any would be predator
and may have been used as displays of dominance or courtship for
mate selection.
For food these
ornithischians most likely cropped low growing vegetation and possibly
reared up to get higher growth in trees. Likely they were like a
high lawn mower in that they ate everything within their reach before
moving in any other plane or direction. Their stomachs have been
described as being "moving fermentation vats that gave off enormous
amounts of heat. This may explain another use of its plates, "as
heat exchangers."
There were actually
two species of Stegosaurs found in North America and the Realm of
the Rattlesnake. This is the smaller of the two called Stegosaurus
stenops. The other was half again larger and called Stegosaurus
ungulatus. There other species found in other parts of the world
at different time periods and they were eventually replaced by their
relatives the Ankylosaurs.
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Allosaurus
Allosaurus was a very
successful and abundant theropod dinosaur found through out the world
from the middle Jurassic to late Cretaceous. In fact the largest carnivores
ever found have been Allosaurs. In North America this ferocious hunter
who's name means "different lizard" came in sizes between 30 and 40
feet in length and weighed 2 to 5 tons.
The fossils have been plentiful and South Dakota, Wyoming, Utah,
Montana, New Mexico, and Oklahoma have all weighed in with some.
One site in the Dinosaur Quarry from Utah contained 44 different
individuals from babies to adults. This and other evidence suggests
that these animals were highly social and possibly hunted in packs.
It is speculated
that the habitats frequented by North American Allosaurs was similar
the plains of Amboseli in Africa. These are hot with monsoons and
dry periods every year. There would be lots of prey species and
often herds would wander in search of water or foliage. this would
prompt the carnivores to follow the game. Likely this also meant
some established though seasonal home territories for the Allosaurs
family, but the ability to seasonally follow their prey if necessary.
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Opisthias
One of the most
unusual lizards left on this planet is the Tuatara of New Zeland.
Opisthias is an ancestor of this true "living fossil" and likely
looked very similar. The Sphenodon's are currently represented by
only the Tuatara, but that was not always the case. These "lizard-like"
reptiles are not true lizards but are in fact a side-path of evolution
that started in the Middle Triassic and continue down to the one
species left today. Some relatives took to the water and became
known as the pleurosaurs. Others were very similar to today's living
fossil, in fact the same basic body type and lifestyle has been
running virtually unchanged for nearly 200 million years.
Opisthias was a
late Jurassic reptile that likely lived on small creatures like
insects, worms, and small lizards in a lifestyle similar to modern
day New Zealand's last surviving member of the family.
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Edmontonia
A member of the
Nodosaurs (which lack tail clubs or spikes) the four ton and 20
plus feet Edmontonia, meaning near Edmonton, was the closest thing
to invulnerable in the Pacific Northwest dinosaur enclave that existed
in the late Cretaceous North America. With its flexible armor, long
and sharp shoulder spikes, and a two layer boney head it would be
surprising that these subgroup of the ankylosaur dinosaurs were
often preyed upon.
Climate and habitat
at this time favored certain species of dinosaurs over others. Temperatures
were up about 75 million years ago as was humidity. There were peat
bogs and bald cypress swamps. Just back from these areas and inland
were much flatter areas composed of river systems flowing to the
seas. Many feeder and tributary stream channels crisscrossed the
region and greatly effected the many dinosaurs in the area. Nearly
half the plants found in this region were flowering. Cycads, ferns,
katura trees, fern trees, and many types of conifers dominated the
flora. The lower and tough members of these plants were preferred
by Edmontonia and they were also likely to favor more open scrub
land closer to the sea. It would not have been all that usual for
them to occasionally see an elasmosaur far up the rivers looking
for a fishy meal.
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Einiosaurus
Among the strangest
looking of the ceretopsian dinosaurs was the Einiosaurus meaning
"buffalo lizard." This late Cretaceous horned dinosaur has only
been found in Northern Montana and in fact may have been relatively
rare and in an isolated population separated from its more common
contemporaries such as Triceratops or Styracosaurus. Not much is
known about this recently discovered dinosaur but it likely behaved
as did most of the other horned dinosaurs.
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Daspletosaurus
This coelurosaur,
a likely ancestor of T rex, was truly a "frightful lizard." At 3
tons and over 30 feet in length this fast meat eating dinosaur was
certainly the king of his late Cretaceous territory. In time Daspletosaurus
was earlier than the rex but likely hunted the same prey in much
the same manner. Another formidable carnivore at the same time and
place was the somewhat more slender tyrannosaurid Albertosaurus.
It is likely that little competition existed between these two species,
much like lions and leopards coexist on the same African plain.
Like all tyrannosaurids
this meat eating creature had only two arms, powerful jaws, and
thick sharp teeth able take very large bites out of its prey. The
size and depth of these bites may well have killed the victim from
shear shock rather than actual attach trauma or blood loss.
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Palaeosaniwa
A close relative
of monitor lizards Palaeosaniwa "before Saniwa" (another true lizard
form the start of the mammals reign) was roughly the size of the
more modern Komodo Dragon. This puts it in the 10 to 11 foot and
350 pound range. The varanoid lizards of the past included forms
like the ocean going mosasaurus which grew to lengths up to nearly
50 feet and Estesia which is believed to be venomous and related
to today's Gila Monsters. Some scientists believe that snakes evolved
from varanids like Palaeosaniwa but currently there is debate on
whether that is the case or not.
Monitor lizards
are true opportunists. They will usually eat almost anything from
worms and fish to mammals and carrion. Some like the Komodo are
ambush hunters and some are simply opportunists that will eat literally
anything that is edible and will fit in the mouth. It is very likely
that Palaeosaniwa lived a lifestyle very much like today's more
modern but not very much changed from their earlier ancestors.
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Corythosaurus
This hadrosaur
from the late has a crest much like Grecian warriors and thus its
name means "Corinthian helmet lizard." It is closely related to
Iguanodon and is called a duckbill dinosaur because it had no teeth
in the front of its mouth and instead had a horny duckbill look.
The teeth started way back in the jaw which is highly unusual as
plant eating dinosaurs as a whole just swallowed plants whole and
let the stomach digest the mass. In addition these teeth were self
sharpening and self renewing.
There has been
a little debate as to how much time the duckbill dinosaurs spent
walking on 2 legs versus all 4 and no real determination has been
made. But the shape of the front feet indicate that they certainly
could walk on all fours. There has also been much speculation on
exactly what the high crest on the head was for. Modern research
with catscan x rays seem to show that the hadrosaurs used these
unusual shaped head ornaments to produce various sounds for either
communicating or attracting mates or both. One can well imagine
that several herds of different hadrosaurs may well have sounded
like an unruly orchestra warming up with a clashing of different
sounds. It was likely to either attract or drive of the meat eaters
of the day depending on whether they were very hungry or music critics.
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Ornithomimus
Meaning "bird mimic"
this extremely fleet ostrich dinosaur was about the size of or slightly
larger than today's flightless ratite ostriches. At fifteen feet
or so in length and over 300 pounds of speed these Cretaceous omnivores
were perhaps the fastest family of dinosaurs ever seen on this planet.
Close relatives were Struthiomimus, and who can forget that scene
in the movie Jurassic Park where T rex grabbed the Gallimimus from
ambush. This was a very good idea of how an ostrich dinosaur could
become prey as they could easily outrun even the fast Tyrannosaurs.
Ornithomimus had
a toothless jaw and what can only be described as a horny bird like
beak. Because of their large brain size relative to other dinosaurs
and their large eyes it is thought that they were among the most
advanced dinosaurs ever to come onto the scene.
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Parasaurolophis
Truly one of the
most unusual looking of all dinosaurs this duckbill dinosaur's name
means "like or beside Saurolophus" and was a member of the hadrosaur
lambeosaurid family. Very few skeletons of this trombone crested
late Cretaceous dinosaur have been found and it may have been much
rarer than its more common cousins but was definitely in parts of
Western Canada, Utah, and New Mexico. This plant eating Ornithopod
ran on two legs but likely browsed on all four and was at least
33 feet long and a head crest of 5 to 6 feet that was possibly attached
to the neck or back with a skin frill.
It is highly likely
that the crests on all the hadrosaur family dinosaurs was used to
sound alarms, troll for mates, and generally communicate with each
other. It is thought that they were all very social animals and
possibly migrated together in large herds for protection from the
many hungry carnivores just waiting for an opportunity for a duckbill
steak.
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More Extict Reptiles
Troodon
The discovery of this small flesh eating
dinosaur Troodon and its relatives was really a milestone in changing
thinking about the behavior of dinosaurs. This fierce and intelligent
hunter is pronounced Troo-o-don and its name means "wound tooth."
This fascinating carnivore was likely
to be closely related in lifestyle to the more well known "raptors"
and were more or less of the same size category or slightly smaller.
They were likely to be ground-dwelling protobirds. Fossil remains
are still limited and we will know more as more are discovered.
It is likely that they were fast,
intelligent, pack hunters, and possibly nocturnal. The best approximation
is that of a pack of small wolves. Remains suggest that they were
social and raised their young in a family atmosphere. They had the
sickle-clawed toes found in the velociraptors and likely lived a
very similar life although they may have hunted different prey much
like coexisting leopards and cheetahs.
Euoplocephalus
It has been said that the herbivores
and carnivores forced each other to evolve in a rapidly escalating
battle of armor vs. firepower. If this is the case, and it seems
very likely it is, then a very successful biological armored vehicle
was Euoplocephalus.
Pronounced you-op-luh-SEF-uh-lus the name means "well
protected head. This tank-like creature was from the late Cretaceous
and is in the Ankylosaur family. It was believed to weigh in the
3 to 5 ton range and averaged 20 feet in length and maybe 8 or 9
feet in width.
What is unusual is that this heavily
armored dinosaur was very likely totally immune to the attack of
the large carnivores like T rex. It's strategy may well have been
to first try and use it's bony and spiked tail to dissuade its attacker
and then if that didn't work to simply hunker down in the sand or
earth, protect its head and just out-wait its adversary. As a side
note there have been T rex leg bones found that were fractured in
just the manner that Euop would have done if it connected.
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