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Name: Stegosaurus

Pronounced: STEG-oh-SORE-us

Meaning: ‘Roof lizard’

Period: Late Jurassic (156 – 144 million years ago)

Group: Stegosaurs (covered lizards)

Size: It was between 8m – 9m long and 2.75m tall at the hips. It weighed around 3100kg.

Diet: Herbivore

Characteristics: The Stegosaurus walked on four legs but there has been much debate about this. It had seventeen bony plates embedded into the skin of its back and tail in two rows, alternating in alignment. These bony plates were not attached to the skeleton, which is why in most fossil finds the plates are detached from the body. The largest of these triangular plates was about 76 cm tall and just as wide. When Marsh described the first fossil of a Stegosaurus, he concluded the plates lay flat on its back. After finding a specimen preserved in mud, he realised the plates stood upright on either side of the spine. Palaeontologists do not agree what the plates were used for. They may have acted as a warning to predators, or helped them to identify each other. Another suggestion is that the plates were used to control the temperature of their body, as there were tiny grooves on the surface of the plates, which possibly contained veins. The amount of blood passing through these veins would determine the dinosaur’s temperature. The Stegosaurus also had spikes at the end of its flexible tail. Compared with the rest of its body, the Stegosaurus had a small head and its brain was around the size of a golf ball. They had flat and blade-like teeth and probably ate low-growing vegetation.

Named by: Othniel Charles Marsh in 1877

Discovery:
The first Stegosaurus fossil was found in Morrison, Colorado in 1876 by M. P. Felch. Others have been found since in Utah, and Wyoming, North America.

Name: Styracosaurus

Pronounced: sty-RAK-oh-sore-us

Meaning: ‘Spiked lizard’

Period: Late Cretaceous (76 – 70 million years ago)

Group: Ceratopsians (horn faces)

Size: It was 5.5m long and stood about 1.8 meters tall. It weighed nearly 3000kg.

Diet: Herbivore

Characteristics: The Styracosaurus walked on four short legs and had a short tail but a huge body. The most prominent feature was the four to six long horns extending from its neck frill. It also had a smaller horn on each of its cheeks and a single horn extending from its nose, which is believed to have been up to 15cm wide and 60 cm long. The function of these horns and frills are still a question of debate. The jaw was tipped with deep, narrow beak and contained shearing cheek teeth, which were believed to have been better at plucking and grasping, than they were at biting. This indicates it ate plants. It probably fed on low vegetation as suggested by the position of the head, but they may have been able to knock down trees due to their large weight. Like other ceratopsians, the Styracosaurus is believed to have been a herd animal, travelling in large groups, as many fossils have been found together.

Named by Lawrence Lambe in 1913

Discovery: The first fossil remains of Styracosaurus were collected in Alberta, Canada by Charles Mortram Sternberg from the Dinosaur Park Formation in 1913.

Name: Ceratosaurus

Pronounced: Keh-RAT-oh-sore-us

Meaning: ‘Horned lizard’

Period: Late Jurassic (150 – 144 million years ago)

Group: Theropods (beast feet)

Size: It was 6m long and 4m tall. It weighed approximately 524kg.

Diet: Carnivore

Characteristics: The Ceratosaurus walked on two legs. Its skull was quite large in proportion to the rest of its body. It had large jaws and blade-like teeth. The front legs were powerful but very short. It also had horns – one on its nose and a smaller pair over the eyes. There has been a lot of debate over what the Ceratosaurus used its horns for. In 1884, Othniel C. Marsh believed they were powerful weapons. Nowadays, this is considered unlikely. In 1985, Norman argued the horns were not used for protection against predators, but for butting contests with its male counterparts to impress females. In 1990, Rowe and Gauthier suggested the horns were probably for display purposes only and consequently would have been brightly coloured and not used for protection, or combat at all.

Named by: Othniel Charles Marsh in 1884

Discovery: Many Fossils have been found in the Dry Mesa Quarry of Colorado in North America and in the Cleveland Lloyd Dinosaur Quarry, central Utah also in North America.

Name: Spinosaurus

Pronounced: SPINE-oh-SORE-us

Meaning: ‘Thorn lizard’ or ‘Spine lizard’

Period: Late Cretaceous (95 – 70 million years ago)

Group: Theropods (beast feet)

Size: It was 18m long and 5m tall. It weighed about 4000kg.

Diet: Carnivore.

Characteristics: The Spinosaurus walked on two legs and had large bony spines coming out of its back vertebrae to form a sail. It is believed the upper spine was very flexible as the vertebrae consisted of ball-and-socket-joints meaning it could arch its back, perhaps to spread its sail, in a similar fashion to opening a fan. This has led palaeontologists to conclude the sail may have been for regulating body temperature. The sail may have also been used to attract mates or give the appearance it was larger than it was. The sail could have been brightly coloured, like the fins of some reptiles today.

Named by: Ernst Stromer von Reichenbach in 1915

Discovery: Fragmentary remains of the Spinosaurus aegyptiacus were found by Richard Markgraf in 1912, in the Bahariya Formation of western Egypt. These incomplete fossils included bony-sail spines up to 1.8m long. However the partial skeleton was unfortunately destroyed during WWII. A potential second species Spinosaurus maroccanushas has since been recovered from Morocco.

Name: Ankylosaurus

Pronounced: an-KIE-loh-sore-us

Meaning: ‘Stiff lizard’

Period: Late Cretaceous (74 – 67 million years ago)

Group: Ankylosaurs (curved lizards)

Size: It was 7m long and 2.5m tall. It weighed between 4000kg – 7000kg

Diet: Herbivore

Characteristics: The Ankylosaurus walked on four legs and is one of the largest armoured dinosaurs. It had a wide, triangular, heavily armoured skull, a gigantic tail-club and enormous chunks of bone embedded in its skin. A study in 2009 showed the larger tail-clubs could shatter bones on impact suggesting their tail-club could have been used for physical confrontations. The back legs were longer than the front legs and studies of fossils suggest it had five toes on each foot. It had a horny beak and small, leaf-shaped teeth suitable for eating plants. Palaeontologists have hypothesised its large stomach probably had a fermentation compartment to help digest more resilient vegetation. Consequently, they would have produced large amounts of smelly gas.

Named by: Barnum Brown in 1908

Discovery: Two skulls and three partial skeletons, including the armour, part of the shoulder girdle, ribs, vertebrae and a tail-club were discovered in the Hell Creek Formation of Montana, in 1906. Other specimens have been found in the Lance Formation along Cow Creek near Niobrara County, Wyoming and in the Scollard Formation, along the Red Deer River in Alberta, Canada. Ankylosaurus tracks have also been sighted near Sucre, Bolivia, South America.

Name: Tarbosaurus

Pronounced: TAR-bow-SORE-us

Meaning: ‘Alarming lizard’

Period: Late Cretaceous (74 – 70 million years ago)

Group: Theropods (beast feet)

Size: It was approximately 10m long and between 4.6m – 5.5m tall. It weighed approximately 6000kg.

Diet: Carnivore

Characteristics: The Tarbosaurus walked on two legs and is similar in size and shape to the Tyrannosaurus. Its front limbs have two fingers. The largest known Tarbosaurus skull is more than 1.3 meters long. Extensive studies of their skulls show they have a unique locking mechanism in the lower jaw and sixty large teeth. Making plaster casts of the insides of some of the skulls has enabled palaeontologists to observe the shape of this dinosaur’s brain. The position of some of the cranial nerve roots suggests it had a keen sense of smell and good hearing. The studies also showed it had a good sense of balance and coordination. Its skull was narrow and its eyes faced primarily sideways. This suggests it relied more on its senses of smell and hearing than on its eyesight.

Named by: Evgeny Maleev in 1955

Discovery: In 1946, a joint Soviet-Mongolian expedition to the Gobi Desert in the Mongolian Ömnögovi Province discovered the first Tarbosaurus skull and some vertebrae in the Nemegt Formation.

Name: Triceratops

Pronounced: tri-SERRA-tops

Meaning: ‘Three-horned face’ from the Greek language, with ‘tri’ meaning three and ‘ceratops’ meaning horned face.

Period: Late Cretaceous (67 – 65 million years ago)

Group: Ceratopsians (horn faces)

Size: It was 9m long and 3m tall. It weighed 5500kg.

Diet: Herbivore

Characteristics: The Triceratops walked on four legs and had three horns, a parrot-like beak and a large frill of about 1m radius. It is believed the horns could have been used to fend off attacks from Tyrannosaurus because in 1997 a partial Triceratops fossil was found, which had a horn that was bitten off, with bite marks that match the Tyrannosaurus. The fossil shows the horn healed after being bitten indicating the Triceratops survived the encounter. Puncture marks on fossil frills show that male Triceratops also used their horns to fight each other, probably to impress females. Triceratops remains are usually found individually, suggesting they may have spent most of their lives alone.

Named by: Othniel Charles Marsh in 1889

Discovery:
Even though the triceratops is one of the most recognisable dinosaurs today, when it was first discovered it was believed to be a type of bison. The first fossils now attributed to Triceratops was a pair of brow horns attached to a skull roof, found near Denver, Colorado in the spring of 1887. Another specimen, collected in 1888 by John Bell Hatcher from the Lance Formation of Wyoming, was at first simply described as another species of Ceratops. It took another year before the dinosaur was actually named.

Name: Dicraeosaurus

Pronounced: die-KRAY-oh-SORE-us

Meaning: ’Forked lizard’ due to the forked spines in its backbone.

Period: Late Jurassic (150 – 135 million years ago)

Group: Sauropods (lizard feet)

Size: There is contradictory information on the height and length of this dinosaur. It weighed approximately 10,000kg

Diet: Herbivore

Characteristics: The Dicraeosaurus walked on four legs and had a very large head with a short, wide neck. The neck contained twelve extraordinarily short vertebrae, each shaped like a ‘Y’ type fork. These forked vertebrae were muscle attachment points. The short vertebrae meant the Dicraeosaurus was not as tall as other sauropods and its tail was also much shorter. Many palaeontologists thought sauropods like the Dicraeosaurus, Brachiosaurus and Diplodocus had a second brain. However, further research has shown what they first believed to be a second brain, was an enlargement in the spinal cord in the hip area. This enlargement was actually larger than the dinosaur’s tiny brain.

Named by: Werner Janensch in 1914

Discovery: Partial Fossils have been discovered in the rocks of Tendaguru Hill in Tanzania, East Africa.

Name: Utahraptor

Pronounced: YOO-tah-RAP-tor

Meaning: Utah plunderer, as the first fossils were found in Utah, North America.

Period: Early Cretaceous (112 – 100 million years ago)

Group: Theropods (beast feet)

Size: It was 6m long and 2m tall. It weighed approximately 1000kg.

Diet: Carnivore

Characteristics: The Utahraptor walked on two legs and had a curved, flexible neck supporting a massive head. It is believed to have had the highest intelligence amongst all the dinosaurs because it had such a big head. Its long tail was excellent for making fast turns and for keeping balance because it had bony rods running along the spine to keep it stiff. There were three fingers on the front limbs which all had large, sharp, curved claws and four toes on its back feet. The second back toe on each foot had a 23cm – 38cm sickle-like claw, whilst the others had shorter claws. Some believe the Utahraptor may have had feathers because they have identified lumps on the skin where the feathers might have been anchored. It may have hunted in packs and probably ate anything it could slash and tear apart with its sharp, serrated teeth, even attacking very large animals.

Named by: James Kirkland, Robert Gaston, and Donald Burge in 1993

Discovery: The first specimens of Utahraptor were found in 1975 by Jim Jensen in the Dalton Wells Quarry in east-central Utah, near the town of Moab, but did not receive much attention. In October 1991, Carl Limoni found a large foot claw in the Cedar Mountain Formation, Gaston Quarry in Grand County, Utah. Further investigation of the Cedar Mountain Formation by James Kirkland, Robert Gaston, and Donald Burge uncovered a fragmentary skeleton, including several large, sharp, curved claws.

Name: Brachiosaurus

Pronounced: BRAK-ee-oh-sore-us

Meaning: ‘Arm lizard’ due to its very long neck that could reach into the tall vegetation like an arm.

Period: Late Jurassic (155 – 140 million years ago)

Group: Sauropods (lizard feet)

Size: It was 30m long and over 15m tall. It weighed between 3000kg – 8000kg

Diet: Herbivore

Characteristics: The Brachiosaurus walked on four legs and had a very small skull on an extremely long neck. They had strong, wide jaws with chisel-shaped teeth suitable for eating leaves off high branches. Large nasal openings have been identified in remains which suggest they had an excellent sense of smell. The Brachiosaurus had 52 teeth, twenty-six along its top jaw and twenty-six along the bottom. Its front legs were longer than its back legs, but its tail was relatively short in comparison to its neck. They probably travelled in herds and may have migrated when their food supply depleted. Brachiosaurus probably hatched out of eggs, in the same way as the other sauropods.

Named by: Elmer S. Riggs in 1903

Discovery: In 1900, Elmer S. Riggs discovered the first Brachiosaurus fossils along the Colorado River in North America. Werner Janensch found more fossils in Tanzania, Africa in 1909. More fossils have been identified by Lapparent & Zbyszewski in Portugal and Algeria in 1957.

Name: Achelousaurus

Pronounced: ah-KEL-oo-SORE-us

Meaning: ‘Achelous lizard’ after the Greek river god, Achelous who was a shape-shifter. During a battle with Hercules, Achelous shape-shifted into a bull and Hercules ripped off one of his horns. The three skulls discovered all have rough areas of bone where horns would normally be, giving the impression its horns were torn off.

Period: Late Cretaceous (83 – 70 million years ago)

Group: Ceratopsians (horn faces)

Size: It was 6m long and 2m tall. It weighed approximately 3000kg.

Diet: Herbivore

Characteristics: The Achelousaurus walked on four legs and had an enormous head, with a bird-like beak and giant, bony frills. They also had a large pair of horns protruding from the top of these giant frills. The male frills were notably larger than the females. The skull of a full-grown Achelousaurus, including the frill and horns, has been estimated to be over 1.5 meters long. Palaeontologists have suggested these large head displays could have evolved to scare away predators, attract a mate, keep cool or could simply be a means of identification.

Named by: Scott Sampson in 1995

Discovery: Fossils have been found predominantly in north-western Montana in North America, mainly in the Two Medicine Formation, which crops out to the east of the Rocky Mountain.

Name: Diceratops

Pronounced: die-ker-ah-tops

Meaning: ‘Two-horned face’

Period: Late Cretaceous (67 – 65 million years ago)

Group: Ceratopsians (horn faces)

Size: It was approximately 7m long and of undetermined height. It has been estimated to weigh between 2000kg – 3000kg

Diet: Herbivore

Characteristics: The Diceratops walked on four legs and had two very distinctive horns as well as an unusual hole in its skull. Many palaeontologists argue this dinosaur was actually a deformed Triceratops, and others claim the Diceratops should be re-assigned as a Nedoceratops (insufficient horned face). Further fossil discoveries are required to resolve this disagreement.

Named by: Richard Swann Lull in 1905

Discovery: The only partial Diceratops fossil to be discovered was a partial skull which was found in eastern Wyoming, in Niobrara County, near Lightning Creek in North Amercia.