Sauropedia

A tribute to the 1993-1998 'Dinosaurs!' collection by Orbis Publishing Ltd.

Lambeosaurus January 27, 2012

Filed under: Ornithopoda — muzillu @ 2:01 pm

Lambeosaurus had a toothless beak and a strange-looking crest on its head.

This herbivorous dinosaur had pebbly skin with scales that fitted together like a mosaic. Lambeosaurus usually walked on four feet, but when threatened it ran off on its powerful hind legs. It relied on its sharp eyes and good hearing to sense danger.

This is a well-known dinosaur, and gives its name to the lambeosaurine hadrosaurids (those with ornate hollow crests on their heads). Its remains were discovered in 1889, but it was not recognized as a distinct genus until 1923. More than 20 fossils have been found. The wide geographical range of the finds suggests that it lived all along the western shore of the late Cretaceous inland sea of North America.

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Name: Lambeosaurus, meaning ‘Lambe’s lizard’, after the Canadian palaeontologist Lawrence Lambe

Size: 15m long

Food: leaves and other parts of plants

Lived: 70-66 million years ago in the Late Cretaceous Period in Alberta, Canada; the USA and Mexico

The hollow crest on the top of the head is in the shape of an axe, with a squarish blade sticking up and a shaft pointing backwards. The square portion is the hollow part with the convoluted nasal passages, while the spike is solid. The crest of the larger species, L. magnicristatus, has a larger hollow portion, bigger than the skull itself, and a very small spike. The skin is thin and covered in small polygonal scales.

As males had larger crests, it may have been a way to tell them apart from females. Some experts think the crest was used as a ‘snorkel’ if Lambeosaurus went underwater. It is more likely that it was used to make sounds. One scientist discovered that, as air moved through the crest of a similar dinosaur, it sounded like a medieval horn. So, Lambeosaurus could have had its own distinctive call.

Inside its huge 2m-long skull, Lambeosaurus had hundreds of small, sharp teeth for crunching pine needles, woody twigs or seeds. When the teeth wore down, new ones grew to replace them.

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Maiasaura June 21, 2011

Filed under: Ornithopoda — muzillu @ 11:17 pm

Maiasaura was named ‘good mother lizard’ because scientists believe it cared for its young after they hatched.

This hadrosaurine is known from a nesting colony found in Montana in the 1970s. It lived in big herds and nested in groups, with possibly as many as 10,000 returning to the same area every year. They probably did so for protection. More than 200 skeletons, embryos, hatchlings, immature and mature adults were found.

 

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Name: Maiasaura, meaning ‘good mother lizard’

Size: about 9m long and 3m high

Food: plants, leaves, fruit and seeds

Lived: between about 90-66 million years ago in the Late Cretaceous in Montana, USA

Maiasaura was a large dinosaur, about as long as a double-decker bus. It usually walked on its long back legs and had a big, flat tail which it held out straight. When feeding on the ground it may have rested on its front legs then reared up on its back legs to reach the leaves of trees. The crest is a short, broad projection above the eyes, and is solid, distinguishing it from the hollow-crested lambeosaurines. The crest, and a pair of triangular projections on the cheekbones, form the basis for the definition of the Maiasaurini. They have batteries of self-sharpening teeth, and a jaw mechanism that allowed the surfaces to grind past each other to chew up tough vegetation.

The nests were hollows, scooped out of muddy ground, and were about the size of a big, round dining room table. The parents may have lined the nest with soft plants, before the female laid between 18 and 30 hard-shelled eggs in it.

Scientists think that Maiasaura mothers, and perhaps fathers as well, guarded the eggs in the nest, protecting them from any dinosaur that tried to steal them. The mothers may have sat on the eggs to keep them warm, going off to feed while other adults watched over them.

When the offspring hatched, the parents looked after them and brought them food. The young dinosaurs ate all sorts of plants as well as fruit and seeds. Maiasaura parents may have chewed up tough plants before giving them to the babies. Experts believe that parents fed the young until they were old enough to leave the nest and find their own food.

Before these offspring were found, scientists thought that female dinosaurs left their offspring to hatch out and take care of themselves alone.

So many nests with skeletons and pieces of eggshell have been found in one place in the USA that some palaeontologists have suggested huge herds of Maiasaura lived in North America. They roamed through the forests, but returned to the same nesting site each year. They probably used the same nests again and again. When the young had grown enough to look after themselves, they stayed with the herd. Eventually, the herd moved on in search of fresh plants to eat.

With no way of defending itself, Maiasaura probably escaped from the big carnivorous dinosaurs by running away and hiding in thick forests. It probably had good eyesight and hearing, which warned it of danger. If Maiasaura was very frightened, it may have plunged into the lakes or rivers. It swam along by waggling its tail and paddling with its front legs.

When palaeontologists discovered a single fossilised nest of Maiasaura in Montana, USA, they decided to excavate the site further. The following year, they returned to their dig and found so many nests, packed closely together, that they named the place ‘Egg Mountain’.

 

 

Tenontosaurus June 20, 2011

Filed under: Ornithopoda — muzillu @ 3:47 pm

Tenontosaurus was a bulky, powerful herbivore that weighed about the same as a large car and was about the same size as a double-decker bus. It had long, powerful limbs and a parrot-like beaked mouth.

Judging by the number of remains that have been found, including 25 skeletons and scattered bones and teeth, Tenontosaurus must have been one of the most abundant herbivores in early Cretaceous North America. It was certainly attractive to carnivores – one skeleton has been found surrounded by the bodies of several Deinonychus that had been killed while attacking it.

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Name: Tenontosaurus, meaning ‘tendon lizard’

Size: 6.5m long

Food: plants

Lived: 110 million years ago in the Middle Cretaceous Period in North America

Tenontosaurus is like a hypsilophodontid but lacks the teeth on the front part of its jaw. Otherwise it is like an iguanodontid, but the classification is still not clear. Its distinctive feature is its very long tail – longer than the rest of the body – and the network of tendons that support the spine. Its long forelimbs and strong finger bones suggest that it walked on all fours for most of the time.

A bulky dinosaur, Tenontosaurus could walk on all fours or pick its way across the landscape on its hind legs. At the end of its front limbs were stocky hands with five fingers on each. Tenontosaurus balanced on the four long toes on each back foot when it stretched into the treetops for a mouthful of leaves or twigs. When it ran, it gripped the ground with its toes, and raised its long, wide tail to balance the weight of its heavy chest and bulging stomach.

Tenontosaurus’ beak had no teeth, but it had ridged teeth running along the side of its beaked mouth. It used these to chew leaves it nipped off trees. When it was attacked, it would lash out with its tail.

 

Iguanodon May 17, 2011

Filed under: Ornithopoda — muzillu @ 10:20 pm

One of the first dinosaurs to be found, Iguanodon had strong back legs with three-toed feet and hoof-like nails.

Iguanodon usually walked on all fours but sometimes got about on just its hind legs. It weighed as much as an elephant.

Famed as being one of the first dinosaurs to be scientifically recognized, Iguanodon became something of a wastebasket taxon over the years. It was thought to have been a four-footed, rhinoceros-like animal until complete skeletons were found in a mine in Belgium in the 1880s. Thereafter, it was restored in a kangaroo-like pose. Now it is largely regarded as a four-footed animal once more.

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Name: Iguanodon, meaning ‘iguana tooth’

Size: up to 10m long and 5m high

Food: plants and leaves

Lived: about 120-110 million years ago in the Early Cretaceous Period in Europe, Mongolia, North Africa

Iguanodon is the archetypal ornithopod. Its head is narrow and beaked, with tough, grinding teeth. Its hands consist of three weight-bearing fingers with hooves. It has a massive spike on the first finger used for defence or gathering food, and a prehensile fifth finger that works like a thumb. The hind legs are heavy and the three toes are weight-bearing. The long, deep tail balanced the animal as it walked.

Although Iguanodon was found and named by Mantell in 1825, the description was based only on teeth. In 2000 the International Commission on Zoological Nomenclature ruled the type species to be I. bernissartensis described in 1881, based on complete skeletons from Belgium.

Scientists speculate that Iguanodon probably walked on its toes, like a cat or dog. When chased by a predator, it could run at speeds of 35km/h. Iguanodon’s tail was stiff and flat, and this helped it to keep its balance.

Several skeletons of Iguanodon have been found close together. This is a clue to the fact that they lived in groups or herds. Iguanodon was the second dinosaur to be named (after Megalosaurus), in 1825.

Iguanodon had very strange hands. These had four fingers and a pointed thumb that resembled a spike. Iguanodon could only move this spike from side to side and used it as a weapon to defend itself. Iguanodon was a herbivore and used its fourth finger to hook down branches for food.

Most of Iguanodon’s day was probably spent searching for food and then chewing it up. It had no teeth at the front of its jaws but used its bony beak to bite off leaves. its back teeth were like an iguana’s, but much larger. There were about a hundred of them.

In 1878, in the small town of Bernissart in Belgium, miners working 322m down a shaft struck a mass of fossil bones. They had dug right through the skeleton of an Iguanodon. Finally, the bones of 39 Iguanodon were discovered there, and were put together. The complete skeletons can still be seen in the Royal Institute of Natural Sciences in Belgium.

 

 

Saurolophus

Filed under: Ornithopoda — muzillu @ 9:30 pm

Despite rows of teeth and its crested head, Saurolophus was unable to defend itself against attack.

Saurolophus is one of the so-called duckbill dinosaurs, known as hadrosaurs. It used its toothless beak to nip off twigs, tough leaves and pine needles, which it ground up between its many rows of teeth.

Confusingly, Saurolophus is only very distantly related to the much more popular Parasaurolophus. The type species S. osborni is known from the remains of at least three individuals. Another species, S. angustirostris, is known from the Gobi desert. Some palaeontologists think it should be the same species as S. osborni, but others think it is a different genus altogether.

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Name: Saurolophus, meaning ‘lizard crest’

Size: 9-12m long and about 3m high

Food: tough plants and leaves, seeds, fruit

Lived: about 80-66 million years ago in western North America and eastern Asia in the Late Cretaceous Period

About as long as a bus, Saurolophus walked on its hind legs, but supported its body on its shorter front legs when feeding. It had no claws on it toes and no way of defending itself directly against carnivorous dinosaurs. However, Saurolophus, like other hadrosaurs, probably relied on keen senses of sight, hearing and smell, as well as their legs, to get out of trouble fast.

Scientists believe that Saurolophus had a pouch of skin on its face. It blew this up like a balloon to send warning signals to the herd or to attract a mate. It may also have used this pouch to increase the noises it made, just as frogs blow out their throats when croaking.

The distinguishing feature of Saurolophus is the prominent spine that rises above the eyes and projects backwards – the uniting feature between the species of Saurolophus is the presence of the backward-pointing spike above the eye. This is formed from the nasal bones that extend backwards and may have been associated with some sound-producing mechanism. The skull is quite narrow for a hadrosaurid, especially across the snout where we would expect to see the duck-like bill. The original species was the most complete to have been found in Canada at the time (1911). The Asian species is much larger.

 

Lesothosaurus May 16, 2011

Filed under: Ornithopoda — muzillu @ 5:53 pm

Lesothosaurus was one of the tiniest dinosaurs that ever lived, and a natural victim for predators.

Lesothosaurus was only about a metre long, which is no bigger than a labrador. This little dinosaur looked very much like a lizard with a long tail. It had a small head with a tough, beak-like mouth which it used to nip off leaves and plants for food. Inside its mouth, along its cheeks, were small teeth shaped like arrowheads. Lesothosaurus used these to chew up the tough and woody parts of plants before swallowing them.

The most primitive ornithischians, such as Lesothosaurus, had not evolved the complex chewing mechanism that was to characterise the later forms. Instead, they would have crushed their food by a simple up-and-down chopping action of the jaws. This is quite an unspecialised feeding method, and these animals may well have eaten carrion or insects as well as plants in order to survive.

 

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Name: Lesothosaurus, meaning ‘reptile from Lesotho’

Size: up to 1m long

Food: low-lying plants

Lived: about 190 million years ago in the Early Jurassic Period in Lesotho, southern Africa

Lesothosaurus is one of the most primitive of the ornithischians, and as such it is difficult to put into a strict classification. It is a small, two-footed herbivore, built for speed. The head, on the end of a flexible neck, is short, triangular in profile, with big eyes. The teeth are arranged in a simple row and, unlike all other ornithopods, the mouth does not seem to have cheeks. The jaw action is one of simple chopping. The snout ends with a horn-covered, vegetation-cropping beak.

Lesothosaurus is very similar to the earlier-discovered Fabrosaurus. However, the Fabrosaurus material is so poor it is impossible to make direct comparisons. If they are the same genus, then the name Fabrosaurus would have to take precedence, being applied first.

Lesothosaurus had a body that was built for speed. It was light and nimble with long, slender back legs. Always on the alert for danger, it could run very fast to escape from carnivorous dinosaurs which tried to capture and kill it.

This dinosaur had no weapons with which to defend itself. However, scientists believe it may have had a way of warning other Lesothosaurus, by a noise or signal, when a predator was on the prowl.

 

Camptosaurus May 13, 2011

Filed under: Ornithopoda — muzillu @ 7:10 pm

The original species of Camptosaurus is based on ten partial skeletons, ranging from juveniles to adults. The species is well-known from the mounted skeletons of a juvenile and an adult collected by Fred Brown and William H. Reed in the 1880s in Wyoming, USA, and put on display in the Smithsonian Institution in Washington DC. The English species is a nomen dubium and may not even be an ornithopod.

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Name: Camptosaurus, meaning ‘flexible lizard’

Size: 7m long and up to 6m tall

Food: plants

Lived: 155-140 million years ago, in the Late Jurassic and Early Cretaceous Periods in western Europe and North America

Camptosaurus is very similar to its cousin Iguanodon, a genus which was a characteristic feature of the landscape of the later early Cretaceous period in Europe. However, its head is longer and lower, and it has four toes on the back foot rather than three. Its heavy body can be carried on four legs or on two, both its front five-fingered feet and its hind feet carrying weight-bearing hooves. Its long mouth contains hundreds of grinding teeth and it has a beak at the front. Its food would be kept in cheek pouches while chewed.

The curved thigh bone of this dinosaur enabled it to run quite fast on its powerful hind legs. As it ran, Camptosaurus balanced its bulky body with its heavy tail. This peaceful dinosaur had no weapons, such as horns or sharp claws, and the only way it could escape larger carnivorous dinosaurs was to run away. The strong, agile rear legs were made for running. It needed to be able to escape from an Allosaurus that could easily overpower even the largest Camptosaurus. Its front legs were small but strong and were used for slow movement during feeding and grubbing around in the brush. It fed with its short front legs on the ground, and the tall hips and rounded curve of the tail gave Camptosaurus a curved or bent profile. This is how it got its name.

It is possible that the original species of Camptosaurus is the only true one. The others may be species of Iguanodon.