Types of Dinosaurs

The Paleozoic Era of our new born planet Earth, was about 542 to 248 million years ago. This era is today divided into the Cambrian, Ordovician, Silurian, Carboniferous and Permian periods. The fish, followed by amphibians, reptiles and mammal-like reptiles, first appeared as multicellular life forms on Earth. The Mesozoic Era was between 248 to 65 million years ago and was followed by the Paleozoic Era. This period is again divided into Triassic, Jurassic and Cretaceous periods. Dinosaurs were the animal group, that had come into existence during the Triassic period of the Mesozic era.

Dinosaurs evolved about 230 million years ago from primitive reptiles called the archosaurs, that were known as ruling lizards during the Mesozoic era.. These lizards were smaller than the dinosaurs and had features that were much different from dinosaurs. Then there is another theory which says there were therapsids may have been a hybrid of mammals and reptiles. So, these creatures could also have been the ancestors of dinosaurs. The early dinosaurs were fleet-footed bipeds. They were meat eaters and plant eaters. They were about 10 to 15 feet in height, according to the fossil remains found on Madagascar islands. The bipeds evolved into quadrupeds. These mammal like creatures, i.e. the therapsids, declined rapidly with the evolution of dinosaurs. The first birds appeared during the Jurassic period of the Mesozoic era. The body size of the dinosaurs also increased during these evolutionary four periods. About 65 million years ago, at the end of Mesozoic era, all dinosaurs and Pterosaurs suddenly disappeared. This end of the dino-era is known as the Cenozoic Era.

When we speak about dinosaurs, the most vivid images of these majestic creatures is created by Steven Spielberg, in the movie Jurassic Park. This movie was adapted from the fictional novel by Micheal Crichton, "The Lost World". People all over the world became fascinated by the creatures that once roamed freely on our planet. There were different types of dinosaurs that were herbivores, carnivores and omnivores. Let us travel back in time and know more about a few of the different types of dinosaurs.

Sir Richard Owen, the British paleontologist, defined the original taxon Dinosauria in 1842. He coined the word Dinosauria, which meant 'fearfully great lizards' in Greek, to refer to the group of extinct reptiles. The following different types of dinosaurs were named according to the different physical features of these 'terrible lizards'.

Type of Dinosaurs: Named According to Their Teeth	Description of Types of Dinosaurs
Astrodon	Astrodon meant 'star-tooth'. It had a long neck and was a herbivore. It was 9 meters long and lived during the Cretaceous period. This star toothed dinosaur was named by Johnston in 1859.
Deinodon	Deinodon means 'terrible tooth'. This carnivore was existed during the late Cretaceous period. This dinosaur is known from only by a dozen, large, fossilized teeth and was named by paleontologist J. Leidy in 1856.
Heterodontosaurus	These dinosaurs had three different kinds of teeth and hence the name. They had sharp cutting front, upper teeth, the cheek teeth for grinding food and two pairs of long canine-like teeth that were could fit into the sockets. Alan J. Charig and Alfred W. Crompton named this dinosaur in 1962.
Hypsilophodon	Hypsilophodon means 'high-crested tooth'. This herbivore was an Ornithopod and was a fast runner. Thomas Huxley was the first to describe a Hypsilophodon, in 1870.

Types of Dinosaurs: Named According to Unusual Head Features	Description of Types of Dinosaurs
Brachyceratops	Brachyceratops means 'short-horn faced'. This dinosaur was a ceratopsian, i.e. a horned, scallop-frilled herbivore with a crest. It was found in the late Cretaceous period and was named in 1914, by C.W. Gilmore.
Homalocephale	Homalocephale means ' level head'. It was a pachycephalosaurid, that is, thick skulled dinosaur. This herbivore walked on two legs and lived during the late Cretaceous period. It was named in 1974, by paleontologists Maryanska and Osmolska.
Pentaceratops	Pentaceratops means 'five-horned-face'. This herbivore had a large bony, scalloped, head frill, a snout horn, 2 large forward facing horns and 2 pointy horn-like cheek bones. It was named in 1923 by paleontologist Henry F. Osborn.
Triceratops	This rhinoceros-like dinosaur had one short horn above a parrot-like beak and two longer horns above its eyes. It was a late Ornithischian dinosaur, which was a bird-hipped, herbivorous dinosaur. It was named by paleontologist Othniel Marsh in 1889.

Types of Dinosaurs: Named According to their Feet	Description of Types of Dinosaurs
Brachylophosaurus	This short crested lizard was a duck-billed dinosaur. It lived during the late Cretaceous period. It was named by paleontologist Charles M. Sternberg, in 1953.
Deinonychus	Deinonychus antirrhopus means 'terrible claw'. This lightly built, fast moving, agile, bipedal, bird-like dinosaur lived in the Cretaceous period. This carnivore was built to kill. It had an IQ that was highest among the dinosaurs and it was named by Ostrum in 1969.
Saltopus	Saltopus means 'leaping foot'. This small, lightly built dinosaur was a bipedal. It had dozens of small sharp teeth and five fingers on its hand. But the fourth and fifth digits were very small. This carnivore was an insect eater and may have been a scavenger. It was named by paleontologist Friedrick von Huene, in 1910.
Velocipes	Velocipes means 'speedy foot'. This carnivore was from the late Triassic period. It was also named by paleontologist Friedrick von Huene, but in 1932.

Types of Dinosaurs: Named According to Unusual Body Features	Description of Types of Dinosaurs
Baryonyx	Baryonyx means 'heavy claw'. This dinosaur had long claws on its hand and long and narrow crocodile-like jaws. A small crest was present on its snout. This carnivore was present during the Cretaceous period. It had a higher IQ than the other dinosaurs and was named by paleontologists Angela C. Milner and Aln J. Charig.
Deinocheirus	Deinocherius means 'terrible hand'. This large, long-legged, bipedal was a carnivore. It was a Coelurosaurid ornithomimosaur theropod and was the fastest among the dinosaurs. It was named by Osmolska and Roniewicz in 1970.
Panoplosaurus	Panoplosaurus means 'totally armored lizard'. It lived during the late Cretaceous period and was named by paleontologist L. Lambe, in 1917.
Centrosaurus	Centrosaurus means 'pointed lizard'. It lived during the late Cretaceous period and was a herbivore. It had scalloped frills, with two hooked spikes near the center. It was also named by paleontologist L. Lambe, in 1904.

Types of Dinosaurs: Named After a Place	Description of Types of Dinosaurs
Andesaurus	Andesaurus means 'Andes mountain lizard'. This was a long Titanosaurid sauropod with an long neck, long tail, quadrupedal, herbivorous dinosaur. It lived during the Cretaceous period and named by Calvo and Jose Bonaparte in 1991.
Denversaurus	Denversaurus mwans 'Dencer lizard'. It was a plated, quadrupedal, herbivore and was named by Robert Bakker in 1988.
Lesothosaurus	Lesothosaurus means 'lizard from Lestho, South Africa'. It was a lightly built, early dinosaur. It was a agile runner and lived from the late Triassic to the early Jurassic period. It was named by paleontologist Peter M. Galton in 1978.
Szechuanosaurus	Szechuanosaurus means 'Szechuan province lizard'. This carnivore lived during the late Jurassic period. It was a Allosaurid theropod and wasnamed by paleontologist Young in 1942.

Types of Dinosaurs: Named in Honor of a Person	Description of Types of Dinosaurs
Drinker	Drinker was a small, herbivorous dinosaur and named in honor of paleontologist Edward Drinker Cope. This Ornithopod lived during the late Jurrasic period and was named by paleontologists Bakker, Galton , Siegwarth and Filla in 1990.
Lambeosaurus	Lambeosaurus means 'Lambe's lizard'. It was a crested, duck-billed dinosaur. It had a forward-leaning, hollow, bony crest that may have been used to produce sounds, enhanced smell or for display during courtship. It lived during the Cretaceous period and was named by Dr. William A. Parks, in honor of Lawrence Lambe.
Othnielia	Othniella was named in honor of paleontologist Charles Othniel Marsh. It was a ornithopod with a horny beak and small skull, with self sharpening cheek teeth. It lived during the late Jurassic Period and was named by Galton in 1977.

Types of Dinosaurs: Named According to their Assumed Behavior	Description of Types of Dinosaurs
Maiasaura	Maiasaura means 'good mother lizard'. This was a large, duck-billed, herbivorous dinosaur. It was the first dinosaur to be found alongside its young, eggs and nests. This should mean that it may have nurtured its offspring. It lived during the late Cretaceous period and was named by Jack R. Horner and Robert Makela in 1979.
Oviraptor	Oviraptor means 'Egg Robber'. It was a bipedal carnivore that had a 'S' shaped neck, arms with three fingered claws, long thin legs and four toe, clawed feet. It had a large brain compared to its body size and lived during the late Cretaceous period. It was described by iHenry F. Osborn in 1924.

These were just a few of the many different types of dinosaurs that once walked our planet. These were probably the most successful groups of animals that survived, evolved and formed diverse living habits. 'How did dinosaurs die?', is an enigmatic question with many hypothetical answers and theories, put forward by scientists, paleontologists and researchers. The mass extinction of dinosaurs marked an end of 'Age of Dinosaurs' and paved way for the 'Age of Mammals'. Mammals were pushed to extinction during the Age of Dinosaurs. Maybe the dinosaur extinction was mother nature's decision to allow the growth and survival of mammals. Whatever the reason, it is a game of 'survival of the fittest' and dinosaurs seemed to have lost the race, due to some unexplained phenomenon. Dinosaurs have always fascinated the survivors in the line of evolution, the Homo sapiens sapiens. There are many different types of dinosaur fossils discovered and many more to be discovered yet. This article has just tried to cover a few dinosaurs and burn a flame of curiosity in your minds, to know more about these lost creatures.