Sauropedia

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

Kentrosaurus January 30, 2012

Filed under: Thyreophora — muzillu @ 5:42 pm

A sharp spike on each shoulder of this dinosaur gave it extra protection from large predators. Kentrosaurus grazed on low-growing plants with its small head close to the ground. It walked on four chunky legs that carried its heavy body. Kentrosaurus lived at the same time as Stegosaurus, but was only about a quarter of its size.

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Name: Kentrosaurus, meaning ‘pointed lizard’

Size: 2.5m long and about 1m high

Food: low-growing plants

Lived: 150-140 million years ago in the Late Jurassic Period in Tanzania, East Africa

The nine pairs of plates on the neck and back are very much narrower than those of Stegosaurus, and the five pairs of spines run in a double row right down the tail. Near the front of its back, the spikes were quite flat. They became more narrow and pointed from its middle to the end of its tail. Another pair of spines projects sideways from the shoulders.

Unlike more advanced stegosaurs, it seems Kentrosaurus did not have ossicles across its body embedded in the skin. Kentrosaurus may have used its sharp spikes to defend itself rather like today’s porcupines do. The little skull contains a tiny brain with well-developed olfactory bulbs. This suggests Kentrosaurus had a very good sense of smell, which would have aided food gathering.

Kentrosaurus lived among some of the largest dinosaurs, the gigantic Giraffatitan and Dicraeosaurus, in what is now Tanzania, East Africa.

This stegosaur was excavated between 1909 and 1912 from the Tendaguru site by a team from Germany. Several hundred Kentrosaurus bones were found, suggesting that something like 70 individuals died there. The group find suggests that it may have been a herding animal. Two mounted skeletons were prepared for the Humboldt Museum in Berlin, Germany, but one was destroyed by bombing during World War II.

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Diplodocus January 27, 2012

Filed under: Sauropoda — muzillu @ 2:54 pm

The familiar long, low sauropod is known as Diplodocus. It is well-known from the many casts of the graceful skeleton of D. carnegii, the second species to be found. The casts, which appear in museums throughout the world, were excavated, reproduced and donated with finance provided by the Scottish-American steel magnate Andrew Carnegie in the early years of the 20th century.

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Name: Diplodocus, meaning ‘double beam’

Size: 27m (up to 40m in the case of D. hallorum) long and 3.6m high

Food: plants and leaves from trees

Lived: 150-138 million years ago in the Late Jurassic Period in North America

When humans walk, the movement of the ankles make the body move up and down. For sauropods like Diplodocus, any movement of their heavy bodies used up a lot of energy. Fossilised footprints show that sauropods had broad, round feet like an elephant’s, with short stubby toes.

A sort of wedge may have raised Diplodocus’ toes from the ground, just like the heel of a shoe. This meant that muscles did not have to work so hard to support the dinosaur’s body as it walked.

From its tiny head to the tip of its enormous tail, Diplodocus had a long line of bones called vertebrae. Its neck had 15, its back 10, and its tail about 70.

The neck and tail are finely balanced and as a result, Diplodocus could probably have raised itself on to its hind legs to reach high into the trees. The wear on the teeth shows that it could browse high in the treetops or among the undergrowth. Finds in the 1990s have led American palaeontologist Steven Czerkas to suggest that there may have been a row of horny spines down the neck, back and tail.

Diplodocus was built rather like a suspension bridge, with its front and back legs acting like twin towers. On an actual bridge, cables support the road that runs between the towers. Diplodocus’ long backbone was supported by muscles. So that the neck and tail could move easily, a tendon probably ran along the length of its backbone.

Diplodocus could fight off predators with its powerful whiplash tail, or rear up on its back legs using its tail as support. This freed the dinosaur’s massive front legs for defence. A large, curved claw on the inner toe could also be used as a sharp weapon.

Diplodocus’ neck was not as long as that of its Chinese cousin, Mamenchisaurus. Compared to the latter’s neck, which was 11m long, Diplodocus’neck was ‘only’ 7.5m long and its enormous weight was balanced by a long tail, which stopped the giant from tipping over. The bones that were hidden beneath Diplodocus’ skin and muscle were designed for strength and support, rather than speed.

In 2004, a presentation at the annual conference of the Geological Society of America made a case for Seismosaurus being a junior synonym of Diplodocus. This was followed by a much more detailed publication in 2006, which not only renamed Seismosaurus as Diplodocus hallorum, but also speculated that it could prove to be the same as D. longus.

 

Lambeosaurus

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.

 

Massospondylus January 25, 2012

Filed under: Sauropoda — muzillu @ 12:04 pm

Massospondylus was one of the first herbivorous dinosaurs to appear on land. It had a small head and a long neck and tail. By tilting back on its hind legs, it could reach shoots and leaves at the top of tall trees.

The first Massospondylus specimen to be found consisted of a few broken vertebrae shipped to Sir Richard Owen, in London, from South Africa in 1854. Since then, the skeletons of more than 80 individuals have been found across southern Africa. There has even been a nest of six eggs found that have been attributed to Massospondylus. Another possible specimen has been found in Arizona, which may indicate that this was a very widespread animal.

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Name: Massospondylus, meaning ‘massive vertebra’

Size: 4m long

Food: plants and leaves from trees

Lived: about 200-180 million years ago in the Early Jurassic Period in southern Africa and North America

Massospondylus‘ teeth are large, some serrated and some flat. It is usually shown as a much more slender animal than other prosauropods of the same size. It has five fingers, but the fourth and fifth are very small. The huge, clawed first finger could be curved over, thumb-wise, across the second and third, making this a versatile hand.

When this dinosaur was discovered, small pebbles were found by its ribcage. Experts think Massospondylus may have swallowed these stones to help it digest its food. When food was swallowed, it was ground down by the stones. They worked like the blades of a food mixer to mash the leaves into a thick, mushy soup so that the dinosaur was able to absorb all the nutrients its large body needed.

To defend itself, Massospondylus had a huge thumb with a long, curved claw. Together with the second and third fingers, the thumb may also have been used for grasping things. The other two fingers were small and weak.

 

Carnotaurus

Filed under: Theropoda — muzillu @ 11:34 am

This large predatory dinosaur had a thick, powerful neck, a bull-shaped head and very short forearms for its size.

Carnotaurus was previously considered to be a member of the group of dinosaurs known as the carnosaurs. However, the group has since been defined to encompass only the allosaurs and their closest kin. It is now classified as an abelisaurid. Carnotaurus had a shorter and deeper skull than Tyrannosaurus and had hornlets over its eyes.

An almost complete skeleton of Carnotaurus was extracted with difficulty from the hard mineral nodule in which it was preserved in Argentina. The deep skull suggests that it may have had an acute sense of smell, but the strength of the jaws and neck implied by the muscle attachments seem at odds with the weakness of the lower jaw and teeth.

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Name: Carnotaurus, meaning ‘meat-eating bull’

Size: 7.5m long and 3.5m high

Food: meat, mainly other dinosaurs

Lived: 100-90 million years ago in the Middle to Late Cretaceous in South America

The head is very short and squashed-looking, with a shallow, hooked lower jaw. Two horns stick out sideways from above the eyes, probably being used for sparring with rivals. The arms are extremely short with no apparent forearms, even shorter than the tiny arms of Tyrannosaurus. They form mere stumps with four miniscule fingers. The skin texture, the best-known of any theropod, has a groundmass of small, pebbly scales but with large, conical scutes forming rows along the sides.

The skull of Carnotaurus has an enormous hole in front of the eye sockets – this is known as the antorbital fossa. All theropods possess this, but only in the abelisaurids is it so large.

Its long, muscular hind legs may have made Carnotaurus much more agile than some other theropods. It would have been able to rush up on its prey and take it by surprise, probably using its sharp claws to slash and grip, while its powerful jaws took out chunks of flesh.

Although Carnotaurus had a very strong skull, it also needed to be light enough to move easily. There were spaces in the sides of the skull to help make it lighter. By jerking its head back, Carnotaurus could tear its prey apart. The teeth in the upper jaw could slice through the flesh, which was held by the lower jaw. Carnotaurus had teeth about 4cm long which curved backwards to help it keep hold of its victim.

Carnotaurus was found in a vast area of grassland and semi-desert called Patagonia in Argentina in 1985. It was an exciting find because the remains gave scientists a very good idea of what this dinosaur’s skin looked like. Along the surface of the body, from head to tail, there were rows of cone-shaped bumps. Rows of big, raised sclaes stood out from the smaller bumps on Carnotaurus’ head, making a pattern around the eyes and on the upper part of its snout.

Carnotaurus was as heavy as a car, almost as tall as an elephant and ran on two legs. Its long backbone was like a big girder supporting the weight beneath. Long rib bones from shoulder to hip gave Carnotaurus extra protection and support.

When Carnotaurus was moving at top speed it would have been unstable without its tail. Carnotaurus used its long, muscular tail to help it keep its balance. This enabled it to push its head forward to seize hold of its struggling prey.

At the top of its short deep head, Carnotaurus had a pair of small, flat horns. These jutted forward over its eyes rather like little wings. Unlike the ceratopsians, such as Triceratops, Carnotaurus’ horns were too small to have been used for defence. Experts think that they may have been coated in extra layers of horn, which would have made them longer. Like stag deer, it is also possible that the male Carnotaurus had larger horns than the females.