From the smallest microraptor that was about 16 inches (40 cm long), to the biggest 35-40 m long sauropods; dinosaurs once roamed and ruled the Earth millions of years ago. More than hundreds of species known, they were the former masters of this planet. But how many of these “terrible lizards“ can you identify by their names? Your guess is as good as mine. Listed below are 10 dinosaurs that many considered as the most well-known dinosaur species that ever lived.

10. Iguanodon

http://en.wikipedia.org/wiki/File:Changing-image-of-Iguanodon.jpg

The Iguanodon meaning “Iguana tooth” is the best known, and most widespread of all the genus of the Ornithopods, the “duck-billed” dinosaurs. A large bipedal (two-legged) dinosaur and characterized by its large thumb spikes, used primarily for defense against enemies, they lived between 130 and 120 million years ago during the early Cretaceous period. A Herbivore (plant-eater), Iguanodon weighed between 4-5 tons, grew to about  20-33 ft (6-10 m) long and stood 9 ft (2.7 m) tall at the hips. In 1825,Gideon Mantell gave its name.

9. Pachycephalosaurus

http://farm4.static.flickr.com/3145/2312232111_ed4175fc89.jpg?v=0

Pachycephalosaurus, meaning “thick headed lizard”, is an omnivore dinosaur that walked on two feet. It lived during the latter part of the Cretaceous Period of what is now North America. Pachycephalosaurus had a very thick skull roof with bumps that served as protection for its small brain. Pachycephalosaurus measure nearly 9 ft (3 m) long and up to 250 lbs (115 kg) in weight.

8. Apatosaurus

http://upload.wikimedia.org/wikipedia/commons/4/40/Apatosaurus.gif

Apatosaurus meaning ‘deceptive lizard’, is a genus of sauropod dinosaur that lived about 156-140 million years ago, during the Jurassic Period. A well-known plant-eating dinosaur,  Apatosaurus was probably one of the biggest land animals that ever lived, with adults reaching  an average length of 70-90 feet (21-27 m) and weighed at 33-38 tons. A long-necked dinosaur with a long whip-like tail, Apatosaurus was a herbivore (plant-eater) animal. Though its posterior appendages were slightly longer than its hind limbs, it had the ability to walked on four feet. It was named by Othniel C. Marsh in 1877.

7. Stegosaurus

http://commons.wikimedia.org/wiki/File:Ba%C5%82t%C3%B3w_Park_Jurajski_001.jpg

Stegosaurus meaning “roof-lizard”  is a herbivorous, four-legged dinosaur that lived during the late Jurassic period approximately 156-140 million years ago. In 1876, M. P. Felch discovered the first Stegosaurus fossil in Colorado, USA, and since then other skeletons have been found. Stegosaurus can be easily identified by the two pairs of long spikes on its tail and its back that had large, double row of kite-shaped plates. Averaging around 26-30 feet long (8-9 m) long,  9 feet (2.75 m) tall at the hips and weighed 6,800 pounds (3100 kg), the four-legged Stegosaurus is one of the most easily identifiable dinosaurs. However, despite its overall size, Stegosaurus had a small head and a walnut-sized brain. It was named by Othniel Marsh in 1877.

6. Troodon

http://www.flickr.com/photos/67904692@N00/2504931076/

Troodon meaning “wounding tooth,” was a small, fast-moving, intelligent, meat-eating dinosaur  that inhabited the Earth during the late Cretaceous period. Troodon was discovered in 1855 in North America. Approximately around 6.5 ft (2 m) long  and weighed about 110 lbs (50 kg), it had very long, slender limbs that suggest that the dinosaur is an agile, reflexive hunter. Troodon had a long skull that cased a relatively large brain, and one obvious long toe claw. A known meat-eater, Troodon was believed to feast on other small mammals, lizards, and other invertebrates.

5. Velociraptor

http://en.wikipedia.org/wiki/File:Velociraptor_BW.jpg

Velociraptor meaning ’swift seizer’ is one of the popular small, predatory dinosaurs that lived about 70 million years ago during the Cretaceous Period . About the size of a turkey, Velociraptor were covered with feathers and walked on two legs. It has a extremely long tail and possessed a down-curved claws on each hind foot. Adults grew to about 2.07 m (6.8 ft) long, 0.5 m (1.6 ft) high at the hip, and weighing up to 15 kg (33 lb). Velociraptor can be distinguished from other dromaeosaurids by its long, uniquely up-curved and low skull, which grew up to 25 cm (9.8 in) long.

4. Parasaurolophus

http://www.flickr.com/photos/orinrobertjohn/234253488/

Parasaurolophus meaning “near crested lizard” is a duck-billed dinosaur that lived during late Cretaceous Period, about 76-73 million years ago. It was a herbivore that walked on either two legs or four. Parasaurolophus is known for its large, elaborate cranial crest, that extended out the back of its head. Scientists believe that this crest was used to aid its vision, for acoustic resonance, and for regulating temperature. Up to now, no complete skeleton of a Parasaurolophus has ever been found. However, one type of specimen, P. walkeri showed that the animal is estimated at 9.5 meters (31 ft) long. A skull found, including the crest is about 1.6 meters (5.2 ft) long.

3. Deinonychus

http://www.flickr.com/photos/aarongustafson/27464271/

During the early Cretaceous Period, or approximately 115-108 million years ago,    Deinonychus used to roamed the Earth. It got its name “Terrible claw” because the second toe of each rear foot had a big sickle-shaped claw. Though Deinonychus was small, it was a fast and swift animal capable of deadly attacks. The dinosaur used its huge claws to cut through its prey. One known species, Deinonychus antirrhopus, stood  about 8-10 feet (2.5-3 meters), about 73 kilograms (161 lb) in weight, and a hip height of 0.87 meters (2.85 ft). Recent findings have proven that, like its cousin the Velociraptor, the Deinonychus had feathers.

2. Triceratops

http://www.flickr.com/photos/mokaiwen/2297648342/

About 72-65 million years ago, during the end-part of the Cretaceous period, Triceratops roamed the earth. Triceratops possessed a muscular build, with strong legs and is Averaging about 30 feet (9 m) long, 30 feet long, 2.9 to 3.0 m (9.5–9.8 ft) in height, and weighs up to 6-12 tons, Triceratops possessed a muscular build. Triceratops main features included: a large bony frill that protects its head that has three long horns used to defend itself against enemies and used  all four limbs in walking.

1. Tyrannosaurus Rex

http://www.flickr.com/photos/currybet/35591553/

Tyrannosaurus, meaning ‘tyrant lizard’ was a genus of theropod dinosaur. Generally called T. Rex or Rex by many, it is one of the largest flesh-eating dinosaurs that ever lived. Adult Rex could reached 40 feet high, up to 4 meters (13 ft) tall at the hips, and averages more than 6 tons in weight. The tyrannosaurus is bipedal, making used of its two legs and tail to stabilize its enormous head. A remarkable feature of T. Rex has powerful legs and mouth and a relatively useless small front limbs. To date, about 30 specimens of Tyrannosaurus rex have been identified through fossilized remains.