From Sauropods to Tyrannosaurs: The 15 Main Dinosaur Types

01

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Tyrannosaurs

A Tyrannosaurus rex skeleton in a museum lobby — An impressive Tyrannosaurus rex skeleton in a museum lobby.
Mark Wilson / Newsmakers

Tyrannosaurs were the killing machines of the late Cretaceous period. These huge, powerful carnivores were all legs, trunk, and teeth, and they preyed relentlessly on smaller, herbivorous dinosaurs (not to mention other theropods). Of course, the most famous tyrannosaur was Tyrannosaurus rex, though less well-known genera (such as Albertosaurus and Daspletosaurus) were equally deadly. Technically, tyrannosaurs were theropods, placing them in the same larger group as dino-birds and raptors. Find out more in an in-depth article about tyrannosaur behavior and evolution.

02

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Sauropods

A Brachiosaurus, a typical sauropod, roams a desert — The Brachiosaurus is an example of a typical sauropod.
Nobu Tamura / Wikimedia Commons / CC BY 2.0

Along with titanosaurs, sauropods were the true giants of the dinosaur family, some species attaining lengths of more than 100 feet and weights of more than 100 tons. Most sauropods were characterized by their extremely long necks and tails and thick, squat bodies. They were the dominant herbivores of the Jurassic period, though an armored branch (known as the titanosaurs) flourished during the Cretaceous. Among the most well-known sauropods are dinosaurs in the genera Brachiosaurus, Apatosaurus, and Diplodocus. For more, see an in-depth article about sauropod evolution and behavior.

03

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Ceratopsians (Horned, Frilled Dinosaurs)

A group of young Hypacrosaurus dinosaurs approach a couple Rubeosaurus ovatus ceratopsians in the woods — A group of young Hypacrosaurus dinosaurs approach a couple Rubeosaurus ovatus ceratopsians.
Sergey Krasovskiy / Getty Images

Among the oddest-looking dinosaurs that ever lived, ceratopsians—"horned faces"—include such familiar dinosaurs as Triceratops and Pentaceratops, and are characterized by their huge, frilled, horned skulls, which were one-third the size of their entire bodies. Most ceratopsians were comparable in size to modern cattle or elephants, but those in one of the most common genera of the Cretaceous period, Protoceratops, weighed only a few hundred pounds. Earlier Asian varieties were only the size of house cats. Find out more in an in-depth article about ceratopsian evolution and behavior.

04

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Raptors

Velociraptor, the world's most famous raptor.
Leonello Calvetti / Stocktrek Images

Among the most feared dinosaurs of the Mesozoic Era, raptors (also called dromaeosaurs by paleontologists) were closely related to modern birds and are counted among the family of dinosaurs loosely known as dino-birds. Raptors are distinguished by their bipedal postures; grasping, three-fingered hands; larger-than-average brains; and the signature, curved claws on each of their feet. Most of them were also covered with feathers. Among the most famous raptors are those in the genera Deinonychus, Velociraptor, and the giant Utahraptor. For more, check out an in-depth article about raptor evolution and behavior.

05

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Theropods (Large, Meat-Eating Dinosaurs)

Ceratosaurus, a typical theropod dinosaur.
Elena Duvernay / Stocktrek Images

Tyrannosaurs and raptors made up only a small percentage of the bipedal, carnivorous dinosaurs known as theropods, which also included such exotic families as ceratosaurs, abelisaurs, megalosaurs, and allosaurs, as well as the earliest dinosaurs of the Triassic period. The exact evolutionary relationships among these theropods is still a matter of debate, but there's no doubt they were equally deadly to any herbivorous dinosaurs (or small mammals) that wandered across their path. Find out more in an in-depth article about the evolution and behavior of large theropod dinosaurs.

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Titanosaurs

The golden age of the sauropods was the end of the Jurassic period, when these multiton dinosaurs roamed all Earth's continents. By the beginning of the Cretaceous, sauropods such as those in the Brachiosaurus and Apatosaurus genera had gone extinct, to be replaced by the titanosaurs—equally large plant-eaters characterized by (in most cases) tough, armored scales and other rudimentary defensive features. As with sauropods, the frustratingly incomplete remains of titanosaurs have been found all over the world. See an in-depth article about titanosaur evolution and behavior.

07

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Ankylosaurs (Armored Dinosaurs)

Minmi, one of the smallest ankylosaurs yet identified.
Matt Martyniuk / Wikimedia Commons

Ankylosaurs were among the last dinosaurs standing 65 million years ago, before the K-T Extinction, and with good reason: These otherwise gentle, slow-witted herbivores were the Cretaceous equivalent of Sherman tanks, complete with armor plating, sharp spikes, and heavy clubs. Ankylosaurs (which were closely related to stegosaurs) seem to have evolved their armament mainly to ward off predators, though it's possible that males fought each other for dominance in the herd. See an in-depth article about ankylosaur evolution and behavior.

08

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Feathered Dinosaurs

Epidexipteryx, a dino-bird closely related to Archaeopteryx.
Nobu Tamura / Wikimedia Commons / CC BY 3.0

During the Mesozoic Era, there wasn't just one "missing link" that connected dinosaurs and birds but dozens of them: small, feathered theropods that possessed a tantalizing mixture of dinosaur-like and birdlike features. Exquisitely preserved feathered dinosaurs such as Sinornithosaurus and Sinosauropteryx have recently been unearthed in China, prompting paleontologists to revise their opinions about bird (and dinosaur) evolution. See an in-depth article about the evolution and behavior of feathered dinosaurs.

09

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Hadrosaurs (Duck-Billed Dinosaurs)

Parasaurolophus, one of the most famous duck-billed dinosaurs.
edenpictures / Flickr

Among the last—and most populous—dinosaurs to roam the Earth, hadrosaurs (commonly known as duck-billed dinosaurs) were large, oddly shaped, low-slung plant eaters with tough beaks on their snouts for shredding vegetation. They sometimes had distinctive head crests too. Most hadrosaurs are believed to have lived in herds and to have been capable of walking on two legs, and some genera (such as the North American Maiasaura and Hypacrosaurus) were especially good parents to their hatchlings and juveniles. See an in-depth article about hadrosaur evolution and behavior.

10

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Ornithomimids (Bird-Mimic Dinosaurs)

Ornithomimus, the prototypical bird-mimic dinosaur.
Tom Parker / Wikimedia Commons / CC BY-SA 4.0

Ornithomimids (bird mimics) didn't resemble flying birds but rather land-bound, wingless ratites such as modern ostriches and emus. These two-legged dinosaurs were the speed demons of the Cretaceous period; species of some genera (such as those in Dromiceiomimus) may have been capable of hitting top velocities of 50 miles per hour. Oddly, ornithomimids were among the few theropods to have omnivorous diets, feasting on meat and vegetation with equal gusto. For more, see an in-depth article about ornithomimid evolution and behavior.

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Ornithopods (Small, Plant-Eating Dinosaurs)

Muttaburrasaurus, an Australian ornithopod.
Matt Martyniuk / Wikimedia Commons

Ornithopods—small- to medium-sized, mostly bipedal plant eaters—were among the most common dinosaurs of the Mesozoic Era, roaming the plains and woodlands in vast herds. By an accident of history, ornithopods such as those in the genera Iguanodon and Mantellisaurus were among the first dinosaurs ever to be excavated, reconstructed, and named—putting this dinosaur family at the center of innumerable disputes. Technically, ornithopods include another type of plant-eating dinosaur, hadrosaurs. See an in-depth article about ornithopod evolution and behavior.

12

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Pachycephalosaurs (Bone-Headed Dinosaurs)

Skeleton of a Dracorex.
Valerie Everett / Wikimedia Commons / CC BY-SA 2.0

Twenty million years before the dinosaurs went extinct, a strange new breed evolved: small- to medium-sized, two-legged herbivores possessing unusually thick skulls. It's believed that pachycephalosaurs such as those in the genera Stegoceras and Colepiocephale (Greek for "knucklehead") used their thick noggins to battle each other for dominance in the herd, although it's possible their enlarged skulls also came in handy for butting the flanks of curious predators. For more, see an in-depth article about pachycephalosaur evolution and behavior.

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Prosauropods

Unaysaurus, a typical prosauropod.
Celso Abreu / Flickr

During the late Triassic period, a strange, ungainly race of small- to medium-sized herbivorous dinosaurs sprang up in the part of the world corresponding to South America. The prosauropods weren't directly ancestral to the huge sauropods of the late Jurassic period but occupied an earlier, parallel branch in dinosaur evolution. Oddly enough, most prosauropods seem to have been capable of walking on two as well as four legs, and there's some evidence that they supplemented their vegetarian diets with small servings of meat. See an in-depth article about prosauropod evolution and behavior.

14

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Stegosaurs (Spiked, Plated Dinosaurs)

Stegosaurus, the world's most famous spiked, plated dinosaur.
EvaK / Wikimedia Commons / CC BY-SA 2.5

Stegosaurus is far and away the most famous example, but at least a dozen genera of stegosaurs (spiked, plated, plant-eating dinosaurs closely related to the armored ankylosaurs) lived during the late Jurassic and early Cretaceous periods. The function and arrangement of these stegosaurs' famous plates is still a matter of dispute—they may have been used for mating displays, as a way to dissipate excess heat, or possibly both. See an in-depth article about stegosaur evolution and behavior.

15

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Therizinosaurs

Therizinosaurus, the eponymous therizinosaur.
Wikimedia Commons / Public Domain

Technically part of the theropod family—the bipedal, carnivorous dinosaurs also represented by raptors, tyrannosaurs, dino-birds, and ornithomimids—therizinosaurs stood out thanks to their unusually goofy appearance, with feathers, potbellies, gangly limbs, and long, scythe-like claws on their front hands. Even more bizarrely, these dinosaurs seem to have pursued a herbivorous (or at least omnivorous) diet, in sharp contrast to their strictly meat-eating cousins. To find out more, see an in-depth article about therizinosaur evolution and behavior.