Acrocanthosaurus was a large, meat-eating dinosaur. Acrocanthosaurus means "high- spined lizard." No one knows what color this, or any dinosaur, was. Anatomy: Acrocanthosaurus was feet (9-12 m) long and weighed about 5,000 pounds (2300 kg). This theropod dinosaur had a big head, with a 4.5-foot (1.4 m) long skull and 68 thin, sharp, serrated teeth. It had 17-inch (43 cm) spikes extending from its vertebrae along the neck, back, and tail. These spikes may have been covered with skin, forming a thick, fleshy sail along its back. This predator had powerful arms; each hand had three fingers equipped with long, sickle-like claws. When it Lived: Acrocanthosaurus lived during the early Cretaceous period, about million years ago. Fossils: Acrocanthosaurus fossils have been found in Oklahoma, Texas, and Utah (in the USA). Many fossilized tracks have also been found.

Seismosaurus was an enormous, long-necked, whip-tailed, small- headed dinosaur. It measured about feet (39-52 m) long and was roughly 18 feet (5.5 m) tall (measured from the ground to the top of the shoulder). This giant may have weighed about 30 tons (roughly 60,000 pounds). It was among the longest land animals that ever lived. Seismosaurus lived during the late Jurassic Period, from million years ago. Diet: Seismosaurus was an herbivore (it ate only plants). Seismosaurus fossils have been found in New Mexico, USA.

ANATOMY Lambeosaurus was a crested, duck-billed dinosaur. Its forward-leaning, hollow, bony crest was as big or bigger than the rest of its skull and may have been used to produce sounds, enhance its sense of smell, and/or used in courtship displays. Lambeosaurus grew to be about feet long (9-15 m), weighing 5.6 tons. It is the largest-known duck-bill dinosaur. WHEN LAMBEOSAURUS LIVED Lambeosaurus lived during the Cretaceous period, about 83 to 65 million years ago, at the end of the Mesozoic, the Age of Reptiles. LOCOMOTION Hadrosaur footprint.Lambeosaurus walked and ran on two legs, and was a relatively fast dinosaur. It probably went on all fours to forage for plants.

Vulcanodon (pronounced vul-KAN-uh-don) was a long-necked dinosaur that lived during the early Jurassic period, about 208 to 201 million years ago. It was a very early sauropod (a vulcanodontid). Anatomy: Vulcanodon was about 20 feet (6.5 m) long. It was a long- necked, long-tailed plant-eater with a small head, thick legs, and a bulky body. It had nail-like claws on its feet and an enlarged claw on each big toe. Its front legs were relatively long. Name: Vulcanodon means "Vulcan tooth." [Vulcan was the Roman god of fire.]

Pentaceratops was a rhinoceros-like plant-eating dinosaur. It walked on four sturdy legs and had three horns on its face along with a large bony plate projecting from the back of its skull (a frill). Pentaceratops lived during the late Cretaceous period, about million years ago. Anatomy: Pentaceratops had a beak, a snout horn, and two long brow horns. It also had two enlarged, horn-like cheekbones that protruded from its face. It had a very large skull, 9.8 feet (3 m) long, with a very large, bony, scalloped, head frill. Pentaceratops was up to 28 feet (8 m) long.

Chasmosaurus was a horned, frilled, plant-eating dinosaur that lived during the late Cretaceous period, roughly 76 to 70 million years ago. Chasmosaurus means "chasm lizard," referring to holes in its frill. Anatomy: This ornithischian (bird-hipped) dinosaur had a bulky body, a very long skull with a frill (5 feet or 1.5 m long), a toothless beak, blunt cheek teeth, and a short tail. The openings in the bone of the frill were large, indicating that the frill was used more as a display than as a defense. Chasmosaurus was up to feet tall (5-8 m) long. It weighed roughly 3.5 tons (3220 kg). Fossils: Chasmosaurus was named in 1914 by Canadian paleontologist Lawrence Lambe. T

Megaraptor was a large, meat-eating dinosaur with a long, sickle-shaped claw on each foot. This fast-running predator lived during the late Cretaceous period, about million years ago. Anatomy: The second toe on each foot had a 14-inch (35 cm) sickle-like claw, and the other toes had smaller claws. When alive, this claw would have been sheathed in a horny, keratinous material much like our fingernails, making the claw even bigger, longer and sharper. The long tail was used for balance and for fast turning ability. It had a relatively large brain and large, keen eyes. Megaraptor was about feet (6-8 m) long.

Maiasaura was a large, plant-eating, duck-billed dinosaur. Maiasaura was the first dinosaur that was found alongside its young, eggs, and nests. This suggests that Maiasaura nurtured its young. The nests were holes scooped out of the ground, about 6-7 feet in diameter (1.8-2 m), and they contained up to 25 grapefruit-sized eggs each. Maiasaura lived during the late Cretaceous period, about 80 to 65 million years ago. A Maiasaura bone fragment and a piece of eggshell from Maiasaura flew with astronaut Loren Acton on an 8-day mission (Spacelab 2) in This was the first dinosaur in space. Fossils and Name: Maiasaura means "Good Mother Lizard". This dinosaur was first discovered in Montana, USA. Thousands of Maiasaura fossils have been found in western Canada and the United States. Adults, hatchlings, juveniles, nests, eggs and embryos have been found.