Dinosaur Interactive - National Geographic Magazine

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Take a Closer Look at Bizarre Dinosaurs

Click on the dots for each of the 22 dinosaurs to find out more about what they are, where they come from, and what makes them "bizarre."

100 734 images/afrovenator_thumb.jpg images/afrovenator.jpg 734 550 16763904 13369344 Teeth Afrovenator's 60-plus sharp, blade-like teeth allow it to efficiently rip apart the flesh of other dinosaurs. The teeth raise questions about the evolution of dinosaurs after Pangaea split into two landmasses. There were two major classes of predatory dinosaurs as the Cretaceous dawned: the ceratosaurs and the tetanurans. The ceratosaurs are the main group of predatory dinosaurs in the "southern" continents. Afrovenator possesses anatomical features that ally it with Tetanurae, which are rare in the south but dominant in the north. The discovery of Afrovenator shows tetanurans achieved a wide cosmopolitan distribution before the southern continents split apart. 423 10 1 Teeth 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 157 171 -45 -13 16763904 13369344 Afrovenator Pronunciation: aff-ROW-ven-ah-tor Meaning: Hunter from Abaka, Africa (Abaka is the Tuareg name for the region of Niger where the fossils were found) Location: Niger Period: Early Cretaceous Fossil Date: About 135 million years ago Group Within Dinosauria: Theropoda Size: Up to 30 feet (nine meters) long Diet: Carnivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 6 images/amargasaurus_thumb.jpg images/amargasaurus.jpg 734 550 16763904 13369344 Amargasaurus Pronunciation: a-MARG-oh-sore-us Meaning: La Amarga lizard (La Amarga is a valley in Argentina where the fossils were found) Location: Argentina Period: Early Cretaceous Fossil Date: About 130 million years ago Group Within Dinosauria: Theropoda Size: Up to 33 feet (10 meters) long Diet: Herbivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 images/amargasaurus_spine.jpg Spines The long, double row of spines on the back of Amargasaurus were possibly used to hold up a sail-like fleshy flap. The exact purpose of the sail is unclear but temperature regulation, intimidation, and visual display are reasonable possibilities. Photograph by Ira Block 503 10 1 Spines 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 230 138 6 -15 images/carcharodontosaurus_thumn.jpg images/carcharodontosaurus.jpg 734 550 16763904 13369344 Carcharodontosaurus Pronunciation: kar-KAR-o-don-toe-sore-us Meaning: Shark-tooth lizard Location: North Africa (Morocco, Egypt) Period: Late Cretaceous Fossil Date: About 95-97 million years ago Group Within Dinosauria: Theropoda Size: Up to 49 feet (15 meters) long Diet: Carnivore Bizarre Fact: Carcharodontosaurus outsizes Tyrannosaurus by nine feet (2.7 meters), making it one of the largest carnivorous dinosaurs. 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Teeth Shark-like teeth are what give Carcharodontosaurus its name. The teeth are long with serrated edges and are bigger and stronger than the teeth of an actual shark, measuring around four inches (10 centimeters) in length. 423 10 1 Teeth 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 35 106 -30 5 16763904 13369344 Skull Measuring five feet (1.6 meters) long, the skull of Carcharodontosaurus is as long as some humans are tall. 423 10 1 Skull 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 121 114 4 -21 images/carnotaurus_thumb.jpg images/carnotaurus.jpg 734 734 16763904 13369344 Carnotaurus Pronunciation: kar-noh-TORE-us Meaning: Meat-eating bull Location: Argentina Period: Late Cretaceous Fossil Date: About 66-71 million years ago Group Within Dinosauria: Theropoda Size: Up to 24.5 feet (7.5 meters) long Diet: Carnivorous 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 images/carnotaurus_skull.jpg Horns Carnotaurus horns distinguish the dinosaur as an unusually large theropod in the abelisaurid group. Photograph by Ira Block 503 10 1 Horns 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 91 112 3 -26 16763904 13369344 Eyes The eyes of Carnotaurus look forward instead of sideways. Although small, the eyes give Carnotaurus binocular vision and heightened depth perception. 423 10 1 Eyes 0 13369344 10 Verdana 16777215 20 0.3 0 0 false 211 139 5 -17 16763904 13369344 Jaw While Carnotaurus's jaw muscles are very strong, its lower jaw is shallow and not very powerful. Its teeth are short for the size of the animal, but there is no evidence that they are weaker than those of any other dinosaur. These odd proportions leave the exact diet of Carnotaurus unknown. 423 10 1 Jaw 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 217 282 9 4 16763904 13369344 Arms The arms of Carnotaurus are not of much use as they are even smaller than those of Tyrannosaurus, which measure three feet (0.91 meter) in length. 423 10 1 Arms 0 13369344 10 Verdana 16777215 20 0.33 0 0 false 325 347 -47 -17 images/deinocheirus_thumb.jpg images/deinocheirus.jpg 734 500 16763904 13369344 images/deinocheirus_arms.jpg Arms Aside from a few bits of ribs and backbones, the forearms are the only other part of Deinocheirus paleontologists have discovered. Measuring eight feet long (2.4 meters) with ten-inch (25 centimeters) hooked claws, the forelimbs of Deinocheirus are similar to the so-called ostrich dinosaurs (ornithomimisaurs). Each limb has three digits and each is longer than a human arm. Photograph by Ira Block 10 10 1 Arms 0 13369344 10 Verdana 0 8 0 1 0 false 310 285 10 -12 16763904 13369344 Deinocheirus Pronunciation(s): dye-nuh-KYE-rus or day-noe-kye-russ Meaning: Terrible hand Location: Mongolia Period: Late Cretaceous Fossil Date: About 70 million years ago Group Within Dinosauria: Theropoda Size: Eight feet (2.4 meters) long Diet: Unknown Bizarre Fact: Deincoheirus, among the largest known theropods, is projected to be more than 40 feet long (12.2 meters). The size was determined by comparing the arms of Deinocheirus to the skeletons of ornithomimisaurs. 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 images/epidendrosaurus_thumb.jpg images/epidendrosaurus.jpg 734 550 16763904 13369344 Epidendrosaurus Pronunciation: epee-den-dro-sore-us Meaning: Upon the tree lizard Location: China Period: Late Jurassic Fossil Date: About 150 million years ago Group Within Dinosauria: Theropoda Size: Unknown Diet: Carnivore Bizarre Fact: Although the dinosaur's exact size is unknown, paleontologists speculate that Epidendrosaurus was about the size of a house sparrow. 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 images/epidendrosaurus_arms.jpg Hands Along with oversize hands, Epidendrosaurus's third digit is nearly twice as long as its other two digits. The closest modern comparison to the dinosaur's excessively long digit is the aye-aye. Lemurs from Madagascar, aye-ayes use their elongated finger to find grubs and insects in the holes of trees. Photograph by Ira Block 10 10 1 Hands 0 13369344 10 Verdana 0 8 0 1 0 false 164 343 3 5 images/erketu_thumb.jpg images/erketu.jpg 734 550 16763904 13369344 Erketu Pronunciation: er-kee-tu Meaning: The creator god Location: Mongolia Period: Early Cretaceous Fossil Date: About 100-130 million years ago Group Within Dinosauria: Sauropoda Size: 49.2 feet (15 meters) long Diet: Herbivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Neck At 25 feet (7.5 meters), the neck of Erketu is twice as long as its torso and tail. 423 10 1 Neck 0 13369344 10 Verdana 0 8 0 1 0 false 136 211 -14 12 16763904 13369344 Vertebrae Erketu vertebrae have air sacs in that help provide support for the dinosaur's extremely long neck. A single vertebra measures nearly two feet (0.6 meters), longer than any other sauropod vertebra, including Diplodocus, which measures a total length of 90 feet (27 meters). 423 10 1 Vertebrae 0 13369344 10 Verdana 0 8 0 1 0 false 273 195 -10 -24 images/gigantoraptor_thumb.jpg images/gigantoraptor.jpg 734 692 16763904 13369344 Gigantoraptor Pronunciation: jahy-GAN-toe-RAP-tore Meaning: Gigantic robber Location: Mongolia Period: Late Cretaceous Fossil Date: About 70-83 million years ago Group Within Dinosauria: Theropoda Size: Up to 16 feet (4.9 meters) tall and 26 feet (7.9 meters) long Diet: Unknown 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 18 16 -5 16763904 13369344 Legs Despite the size of Gigantoraptor, it has slender and lengthy legs like a bird. The legs are twice as long as the average human's legs. Gigantoraptor's legs suggest it might be a habitual runner, like an ostrich. 423 10 1 Legs 0 13369344 10 Verdana 0 8 0 1 0 false 540 426 11 -17 images/leaellynasaura_thumb.jpg images/leaellynasaura.jpg 734 505 16763904 13369344 Leaellynasaura Pronunciation: lee-ell-in-owe-sore-ah Meaning: Leaellyn's lizard (Leaellyn is name of the daughter of Patricia Vickers-Rich and Thomas Rich, the discoverers of Leaellynasaura) Location: Australia Period: Late Cretaceous Fossil Date: Between 105-110 million years ago Group Within Dinosauria: Ornithopoda Size: Up to ten feet (three meters) long Diet: Herbivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Brain and eyes Big optic lobes in the Leaellynasaura brain, along with huge eyes, provide for sharp vision in the dark, especially during long winters. During the time of Leaellynasaura, Australia was located further south than it is today and experienced long periods of winter darkness. 423 10 1 Brain and eyes 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 105 130 6 -20 16763904 13369344 Mouth Leaellynasaura uses its beak-like mouth to gather vegetation. Leaves, small shrubs, and ferns may have been among the vegetation. 423 10 1 Mouth 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 53 168 -33 8 images/majungasaurus_thumb.jpg images/majungasaurus.jpg 734 550 16763904 13369344 Majungasaurus Pronunciation: mah-jung-ah-SAWR-us Meaning: Majunga lizard Location: Mahajanga Basin, northwest Madagascar Period: Late Cretaceous Fossil Date: About 66-71 million years ago Group Within Dinosauria: Theropoda Size: Up to 20 feet (six meters) long Diet: Carnivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Horn Majungasaurus has a single rounded horn on the roof of its skull. 423 10 1 Horn 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 94 109 4 -18 images/mamenchisaurus_thumb.jpg images/mamenchisaurus.jpg 734 561 16763904 13369344 Mamenchisaurus Pronunciations: mah-MEN-chih-sawr-us or ma-men-chee-sore-uss Meaning: Mamenchi lizard (Mamenchi is the name of the ferry near the site where the fossil was discovered in China.) Location: China Period: Late Jurassic Fossil Date: About 155 to 161 million years ago Group Within Dinosauria: Sauropoda Size: 35 feet (10.7 meters) tall and 69 feet (21 meters) long Diet: Herbivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 13 140 12 8 16763904 13369344 Teeth Although Mamenchisaurus is similar to sauropods in the family Diplodocidae, the two dinosaur groups have different teeth. Mamenchisaurus teeth are spatula-like, as opposed to the pencil-like teeth of diplodocids. 423 10 1 Teeth 0 13369344 10 Verdana 0 8 0 1 0 false 98 44 -47 -2 16763904 13369344 Neck Measuring up to 36 feet long (11 meters), Mamenchisaurus has the longest neck of any known dinosaur. The neck is half of its total length. 423 10 1 Neck 0 13369344 10 Verdana 0 8 0 1 0 false 321 155 6 -23 16763904 13369344 Skull The skull of Mamenchisaurus is tiny compared with the rest of the dinosaur. The heads of sauropods, like Mamenchisaurus, are lightly constructed with lots of joints. When these dinosaurs died, their heads tended to come apart quickly. As a result, many sauropod skeletons lack skulls. 423 10 1 Skull 0 13369344 10 Verdana 0 8 0 1 0 false 155 31 8 -13 images/masiakasaurus_thumb.jpg images/masiakasaurus.jpg 734 734 16763904 13369344 Masiakasaurus Pronunciation: mah-shee-ah-kah-sore-us Meaning: Vicious lizard Location: Mahajanga Basin, northwest Madagascar Period: Late Cretaceous Fossil Date: About 66-71 million years ago Group Within Dinosauria: Theropoda Size: Up to seven feet (two meters) long Diet: Carnivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 images/masiakasaurus_jaw.jpg Teeth Unique among dinosaurs, the front teeth of Maskiakasaurus project forward rather than straight down. These horizontal dagger teeth might have made it easier to catch prey (invertebrates or small vertebrates). Photograph by Ira Block 10 10 1 Teeth 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 541 517 9 -21 images/mononykus_thumb.jpg images/mononykus.jpg 734 560 16763904 13369344 Mononykus Pronunciations: mo-NON-ih-kus or mono-NIKE-us Meaning: One claw Location: Mongolia Period: Late Cretaceous Fossil Date: About 72-74 million years ago Group Within Dinosauria: Therapoda Size: 3.5 feet (1.1 meters) and five feet (1.5 meters) Diet: Carnivore Bizarre Facts: One of the few dinosaurs to make the cover of Time magazine, Mononykus appeared front and center in 1993 as part of a larger story that discussed how new discoveries have dramatically altered previous perspectives on dinosaurs. Mononykus has many bird-like features, including a keeled sternum. A keeled sternum on modern day birds is where the flight muscles are attached. Mononykus also has fused wristbones, a bird-like characteristic that is a necessary flight adaptation. 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 17 168 17 5 16763904 13369344 Forelimb Mononykus has a wide, short forelimb with a single claw. The forelimb is perhaps used to dig insects out of underground burrows, like an anteater. 423 10 1 Forelimb 0 13369344 10 Verdana 0 20 0 20 0 false 300 282 -38 16 images/nigersaurus_thumb.jpg images/nigersaurus.jpg 734 550 16763904 13369344 Nigersaurus (size) Pronunciation: nee-zhayr-sore-us Meaning: Niger lizard Location: Niger Period: Early Cretaceous Fossil Date: About 110 million years ago Group Within Dinosauria: Sauropoda Size: Up to 49 feet (15 meters) long Diet: Herbivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Mouth Broad and flat, Nigersaurus's mouth resembles a vacuum cleaner. The shape allows the dinosaur to feed on plants close to the ground. 423 10 1 Mouth 0 13369344 10 Verdana 0 8 0 1 0 false 37 226 -1 4 16763904 13369344 Skull The skull bones of Nigersaurus are so thin they are almost translucent. The thin skull suggests Nigersaurus did not have strong jaw muscles. 423 10 1 Skull 0 13369344 10 Verdana 0 8 0 1 0 false 40 206 5 -19 16763904 13369344 Teeth An individual Nigersaurus has more than 500 teeth. Each tooth is equivalent in size to a human toddler's tooth. The teeth, located at the front of the jaw, are tightly aligned in three rows. A CT scan showed that behind each tooth are seven replacement teeth. Despite having so many teeth, Nigersaurus did not have a powerful bite. The teeth move against each other in a shearing action, a design better suited for nipping, rather than chomping. 423 10 1 Teeth 0 13369344 10 Verdana 0 8 0 1 0 false 13 232 -6 7 images/paralititan_thumb.jpg images/paralititan.jpg 734 551 16763904 13369344 Paralititan Pronunciation: pa-ral-i-tie-tuhn Meaning: Tidal giant (the skeleton was found in tidal deposits) Location: Bahariya Oasis, Egypt Period: Late Cretaceous Fossil Date: 97 million years ago Group Within Dinosauria: Sauropoda Size: Up to 98 feet (30 meters) from head to tail Diet: Herbivore Bizarre Fact: As long as three double-decker buses, the Paralititan is one of the largest dinosaurs ever discovered and may have served as prey for carnivorous dinosaurs like Carcharodontosaurus. 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Arm The six-foot (1.69 meter) humerus, or upper arm bone, of Paralititan is longer than any known Cretaceous sauropod. 423 10 1 Arm 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 341 325 13 -8 images/parasaurolophus_thumb.jpg images/parasaurolophus.jpg 734 651 16763904 13369344 Parasaurolophus Pronunciation: pa-ra-saw-ROL-off-us Meaning: Beside crested/ridged lizard Location: North America (New Mexico, United States) Period: Late Cretaceous Fossil Date: 70-73 million years ago Group Within Dinosauria: Lambeosaurinae Size: Up to 39 feet (12 meters) long Diet: Herbivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 images/parasaurolophus_crest.jpg Head crest Parasaurolophus possesses a hollow, bony head crest that measures around three feet (one meter) long--bigger than any other hadrosaur's crest. The crest is made up of a complex system of tubes and airways; when Parasaurolophus breathes it makes trombone-like sounds. The sounds most likely serve to find others of its kind when herding and courting, as well as to allow Parasaurolophus to alarm others of danger. Photograph by Ira Block 303 10 1 Head crest 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 215 92 -72 -23 images/sinosauropteryx_thumb.jpg images/Sinosauropteryx.jpg 734 600 16763904 13369344 Sinosauropteryx Pronunciations: sine-oh-sore-op-ter-iks or sye-no-saw-op-tur-icks Meaning: Chinese lizard wing Location: China Period: Early Cretaceous Fossil Date: About 125 to 121 million years ago Group Within Dinosauria: Theropoda Size: Up to three feet (one meter) long Diet: Carnivore Bizarre Fact: Sinosauropteryx's small feather structures provided the first evidence that animals other than birds had feather-like coverings. 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Feathers Along the neck, shoulder, and tail of Sinosauropteryx there is a fine covering of feather-like structures. The feathers are primitive and resemble the down of a baby bird. Each structure is about a quarter of an inch (0.5 centimeters) long. 10 10 1 Feathers 0 13369344 10 Verdana 0 8 0 1 0 false 344 147 12 -17 16763904 13369344 Tail The first Sinosauropteryx discovered was a juvenile, measuring 22 inches (55 centimeters) long. Half of its total length was its tail. 423 10 1 Tail 0 13369344 10 Verdana 0 8 0 1 0 false 66 113 -26 12 images/spinosaurus_thumb.jpg images/spinosaurus.jpg 734 600 16763904 13369344 Spinosaurus Pronunciation: spine-oh-SORE-us Meaning: Spiny lizard/thorn lizard Location: North Africa (Morocco, Egypt) Period: Late Cretaceous Fossil Date: 95-97 million years ago Group Within Dinosauria: Theropoda Size: Up to 46 feet (14 meters) long Diet: Carnivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 21 193 18 5 16763904 13369344 Spines Spines on its back probably supported a massive sail-like structure that rose to a height of almost six feet (two meters) above its hips. This feature makes Spinosaurus unique among large predatory dinosaurs. 10 10 1 Spines 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 438 46 9 -12 16763904 13369344 Teeth and snout Spinosaurids are the only large, carnivorous dinosaurs with crocodile-like snouts and teeth. A long snout may have been useful for catching fish, but Spinosaurus might also have eaten other dinosaurs. 423 10 1 Teeth and snout 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 39 138 0 10 images/styracosaurus_thumb.jpg images/styracosaurus.jpg 734 700 16763904 13369344 Styracosaurus Pronunciations: sty-RAK-oh-sore-us or stih-RAK-uh-sawr-us Meaning: Spiked lizard Location: Alberta, Canada, and United States Period: Late Cretaceous Fossil Date: About 75 million years ago Group Within Dinosauria: Ceratopsia Size: Nine feet (2.7 meters) tall and 17 feet (5.2 meters) long Diet: Herbivore Bizarre Fact: The blood circulation in the skin covering the frill may cause the frill to change colors. 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Horn on nose The large spike on Styracosaurus's nose measures up to two feet (0.6 meters), six inches (15.2 centimeters) long. More primitive members of the group containing Styracosaurus had only a small bump on their nose, but as the lineage evolved, the bump grew in size. The horns of ceratopsians likely proved to be useful in fighting predators. 423 10 1 Horn on nose 0 13369344 10 Verdana 0 8 0 1 0 false 121 427 3 -27 16763904 13369344 Neck The neck of Styracosaurus had sturdy joints that prevented the dinosaur from raising its head above the height of an average adult human. As a result, Styracosaurus spent its time browsing lower-lying plants. 10 10 1 Neck 0 13369344 10 Verdana 13421772 8 0.49 1 0 false 407 421 9 3 16763904 13369344 images/styracosaurus_skull.jpg Neck frills The frills on the neck are a common characteristic of ceratopsian. However, because of limited fossil evidence, the exact arrangement of the frills cannot be determined. Photograph by Ira Block 303 10 1 Neck frills 0 13369344 10 Verdana 0 8 0 1 0 false 434 199 8 -23 16763904 13369344 Snout The beak-like shape of Styracosaurus's snout allows the dinosaur to rip low plants to eat. 423 10 1 Snout 0 13369344 10 Verdana 0 8 0 1 0 false 220 550 -48 2 images/tuojiangosaurus_thumb.jpg images/tuojiangosaurus.jpg 734 734 16763904 13369344 Tuojiangosaurus Pronunciation(s): too-YANG-oh-sore-us or too-oh-jee-ang-oh-sore-uss Meaning: Tuojiang lizard (Tuojiang is a province in China.) Location: China Period: Late Jurassic Fossil Date: About 155-161 million years ago Group Within Dinosauria: Thyreophora Size: Up to 23 feet (seven meters) long Diet: Herbivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Back plates Pairs of bony plates on Tuojiangosaurus's back provide evidence of a continuing evolutionary pattern in the Stegosauria. Instead of being attached to bones, the back plates are embedded into the dinosaur's skin. From a distance the back plates make Tuojiangosaurus appear larger, perhaps helping to scare off potential predators. 10 10 1 Back plates 0 13369344 10 Verdana 0 8 0 1 0 false 352 100 -69 -19 16763904 13369344 images/tojiangosaurus_spike.jpg Shoulder spikes Tuojiangosaurus's protruding shoulder spikes help protect the dinosaur's vulnerable sides. Photograph by Ira Block 10 10 1 Shoulder spikes 0 13369344 10 Verdana 0 8 0 1 0 false 491 370 -5 13 16763904 13369344 Tail The tail of Tuojiangosaurus features four spikes, a typical feature of stegosaurids. The tail has strong muscles that allow the dinosaur to strike predators with great force. 423 10 1 Tail 0 13369344 10 Verdana 0 8 0 1 0 false 142 467 -34 -8 images/tyrannosaurus_thumb.jpg images/tyrannosaurus.jpg 734 651 16763904 13369344 Tyrannosaurus Pronunciation: tie-RAN-oh-sore-us Meaning: Tyrant lizard Location: Western North America (Canada, U.S.A.) Period: Late Cretaceous Fossil Date: Between 65-70 million years ago Group Within Dinosauria: Theropoda Size: Up to 40 feet (12 meters) long Diet: Carnivore 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 18 21 18 5 16763904 13369344 Head The bones in the 4.5-foot (1.4 meter) skull of Tyrannosaurus possess numerous holes that serve to lessen its weight. 423 10 1 Head 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 134 137 -49 -15 16763904 13369344 Mouth The jaw joint of Tyrannosaurus reaches far back into its mouth allowing the mouth to open extremely wide. This feature gives Tyrannosaurus the ability to swallow the equivalent of a human adult. 423 10 1 Mouth 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 138 403 5 -2 16763904 13369344 Teeth Almost 60 huge, sharp, serrated teeth can be found in the mouth of Tyrannosaurus, with some reaching seven inches (20 centimeters) long. 423 10 1 Teeth 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 76 335 -33 6 16763904 13369344 Arms While not comparable in size to the rest of Tyrannosaurus, its three-foot (0.91 meter) arms have two sharp claws and appear to have been relatively muscular. 423 10 1 Arms 0 13369344 10 Verdana 16777215 3 0.3 0 0 false 271 336 -47 -4 images/velociraptor_thumb.jpg images/velociraptor.jpg 734 600 16763904 13369344 Velociraptor Pronunciations: veh-loss-ih-RAP-tor or vel-OSS-ee-rap-tor Meaning: Quick plunderer Location: Mongolia Period: Late Cretaceous Fossil Date: About 80-84 million years ago Group Within Dinosauria: Theropoda Size: 2.5 feet tall (0.8 meters), 5.9 feet long (1.8 meters) Diet: Carnivore Bizarre Fact: In 1971 a group of fossils were discovered depicting the Velociraptor fighting a Protoceratops, a pig-size horned dinosaur. The Velociraptor is biting the Protocertaops, which has the Velociraptor's forelimb in its beak. 423 10 0.001 [Quick Facts] 13369344 16711680 10 Verdana 0 8 0 1 0 false 11 13 3 -3 16763904 13369344 Brain Velociraptor is part of the family Dromaeosauridae, a group that has relatively large brains compared with other dinosaurs. Using a ratio of an animal's brain size to its body size, some scientists believe dromaeosaurids are among the cleverest of dinosaurs. 423 10 1 Brain 0 13369344 10 Verdana 0 8 0 1 0 false 201 30 11 -26 16763904 13369344 Claw Located on both feet, the claw on the second digit of Velociraptor is sickle-shaped and retractable. Velociraptor probably uses the claws to kill its prey. 10 10 1 Claw 0 13369344 10 Verdana 0 8 0 1 0 false 438 487 -43 -17 16763904 13369344 Tail Stiff from rod-like tendons, the tail of Velociraptor could only flex at the base. Velociraptor in order to strike animals with its rear feet might prop itself up on its tail, like a kangaroo would. 14 10 1 Tail 0 13369344 10 Verdana 0 8 0 1 0 false 570 148 -2 -32