BRAINS AND INTELLIGENCE

The EQ or Encephalization Quotient is a simple way of measuring an animal's intelligence. EQ is the ratio of the brain weight of the animal to the brain weight of a "typical" animal of the same body weight.

Assuming that smarter animals have larger brains to body ratios than less intelligent ones, this helps determine the relative intelligence of extinct animals. In general, warm-blooded animals (like mammals) have a higher EQ than cold-blooded ones (like reptiles and fish). Birds and mammals have brains that are about 10 times bigger than those of bony fish, amphibians, and reptiles of the same body size.

The Least Intelligent Dinosaurs: The primitive dinosaurs belonging to the group sauropodomorpha (which included Massospondylus, Riojasaurus, and others) were among the least intelligent of the dinosaurs, with an EQ of about 0.05 (Hopson, 1980).

Smartest Dinosaurs: The Troodontids (like Troödon) were probably the smartest dinosaurs, followed by the dromaeosaurid dinosaurs (the "raptors," which included Dromeosaurus, Velociraptor, Deinonychus, and others) had the highest EQ among the dinosaurs, about 5.8 (Hopson, 1980).

The Encephalization Quotient was developed by the psychologist Harry J. Jerison in the 1970's. J. A. Hopson (a paleontologist from the University of Chicago) did further development of the EQ concept using brain casts of many dinosaurs. Hopson found that theropods (especially Troodontids) had higher EQ's than plant-eating dinosaurs. The lowest EQ's belonged to sauropods, ankylosaurs, and stegosaurids. A SECOND BRAIN?

It used to be thought that the large sauropods (like Brachiosaurus and Apatosaurus) and the ornithischian Stegosaurus had a second brain. Paleontologists now realize that what they thought was a second brain was an enlargement in the spinal cord in the hip area, perhaps containing fat and nerve tissue. This nerve center may have controlled the animal's hind legs and tail and was larger than the animal's tiny brain.

DINOSAUR DEFENSIVE WEAPONS AND MANEUVERS

Dinosaurs were armed with built-in defensive weapons and behaviors that were used for dealing with interspecies rivalry or as protection from carnivores (meat eaters). These included:

Horns, Claws, and Spikes - Many dinosaurs had deadly, knife-like protuberances that were excellent protection from being eaten (for

example, Triceratops and

Kentrosaurus ). Some sauropods had large thumb claws; these were especially prominent in the young and in juveniles.

Large size - Some adult diplodocids (like Apatosaurus, Diplodocus, Supersaurus, etc.) and other dinosaurs were so large that only the hugest carnivores or packs of carnivores were a danger. Armored plating (bony plates fused into leathery skin) -

Ankylosaurids (like Euoplocephalus, Ankylosaurus, and Sauropelta) were plated all over the tops and sides of their bodies. Even their eyelids had armor plating. Only their underbellies were unprotected. To kill an Ankylosaurid, a predator would have had to flip over a terribly heavy animal over - not an easy job. Thick, leathery skin - This would provide only a little bit of protection from predators with sharp, strong teeth like T. rex, Giganotosaurus, and Utahraptor.

Head butting - Pachycephalosaurs (like Pachycephalosaurus, Stegoceras, Wannanosaurus, etc.) and other thick-skulled dinosaurs may used head butting to repel predators.

It had long been thought that Pachycephalosaur's thick domes may have been used for ramming rivals during mating and dominance combat, for attracting mates, and as a last-ditch self-defense against predators. Paleontologist Mark Goodwin of the University of California at Berkeley has analyzed many pachycephalosaur skulls (including those of Pachycephalosaurus), finding no evidence of healed scars. Also, under close analysis, the thick skull bone is not rigid and solid, but porous and fragile when put under extreme pressure. ``It's time to kill the myth ... It certainly wouldn't be in their own best interests to ram heads in a fight,'' said Goodwin ``They would have killed each other, and a couple of bowling balls would hardly make good targets.''

Speed - Leaving a fight can be easier and safer than fighting.

Bludgeon-like tail clubs - Ankylosaurids (like Euoplocephalus and Ankylosaurus) had bony tail-clubs that could easily have been used for defense, which would have been useful for these lumbering, plated grazers. Also, some theropods, like Shunosaurus, Omeisaurus and maybe Mamenchisaurus had tail clubs for protection. Whip-like tail - Some people believe that sauropods may have used their massive tails as a whip to lash at their attackers. This theory seems unlikely given the amount of physiological damage to tail tissue that would be caused by the sudden acceleration near the end of the tail (and the deceleration upon impact). Also, the large sauropods probably grazed on tree leaves, giving them no room to whip their tail around without hitting tree trunks and getting severe tail damage.

SEXUAL DIMORPHISM

It is very difficult to determine which fossils were male and which were female. Some paleontologists have theorized that the males of some species may have had larger crests, frills, or other showy structures that were used in courtship displays, mating rituals, and/or intraspecies rivalry (contests among members of the same species, like territorial disputes and mating competition), very much like many modern-day animals. The development of these structures occurs with sexual maturity, so example of juvenile fossils would have little or none of these structures.

Hadrosaurs Originally, fossils very similar to Parasaurolophus but with smaller crests were thought to belong to a separate species of Parasaurolophus. A similar situation existed for Lambeosaurus and many other crested dinosaurs (the lambeosaurine duck-bills) and dome-headed dinosaurs (Pachycephalosaurs). In 1975, the Canadian paleontologist Peter Dodson showed that many of the supposedly separate species of frilled/crested dinosaurs were the females and juveniles of the species. The anatomist James A. Hopson also interpreted the crest and dome sizes as differing in males and females within a species.

Ceratopsians - Many paleontologists believe that the ceratopsians (like Triceratops and Protoceratops) used their horns and frills in territorial disputes, in mating competitions and for attracting females.

Pachycephalosaurs, the dome-headed hadrosaurid dinosaurs, also exhibit sexual dimorphism. The anatomist James A. Hopson realized that crest and dome size differs in the male and female of the species.

DINOSAUR OFFENSIVE WEAPONS AND MANEUVERS

Many dinosaurs were armed with built-in weapons that were used for killing and eating prey, for dealing with interspecies rivalry, or as protection from fellow carnivores (meat eaters). These included:

Big, sharp, pointed teeth - Largest, sharp teeth of most carnivores are for tearing flesh from prey.

Clawed feet - Many dinosaurs claws on feet and/or hands. Dromaeosaurids and Megaraptor had a huge retractible sickle-like claws on each foot. Grasping hands with clawed fingers - good for catching and slashing prey. Large size - Some dinosaurs, like Giganotosaurus and T. rex were so large that they were at the top of the food chain, and could eat any animal that they could catch. Speed and agility- In order to eat, a predator must catch its prey. The only surviving dinosaurs, the birds, evolved from the speedy, bird-like theropods.

Modern-day birds have excellent good color vision; it is likely that the bird-like dinosaurs (advanced theropods like the coelurosaurs) also had color vision. This would have helped them find and catch their prey (just as hawks use their acute vision to spot prey).

DINOSAUR REPRODUCTION

Very little is known about dinosaur courtship, rivalry, pairing and mating.

EGGS Dinosaurs hatched from eggs laid by females after sexual reproduction. The eggs were round or elongated and had hard, brittle shells. Internally, these eggs were similar to those of reptiles, birds and primitive mammals; they contained a membrane (called the amnion) that kept the embryo moist. Some dinosaurs cared for their eggs, others simply laid them and then abandoned them.

The first fossilized dinosaur eggs found (and the biggest yet to be found) were football-shaped Hypselosaurus eggs found in France in 1869. These eggs were 1 foot (30 cm) long, 10 inches (25 cm) wide, had a volume of about half a gallon (2 liters), and may have weighed up to 15.5 pounds (7 kg). The smallest dinosaur eggs are about 1 inch across; they are from Mussaurus.

Many fossilized dinosaur eggs have been found, at over 200 sites in the USA, France, Spain, Mongolia, China, Argentina, and India. Very rarely, the eggs have preserved parts of embryos in them, which can help to match an egg with a species of dinosaur. Without an embryo, it it difficult to match an egg to a dinosaur species. The embryo in an egg sheds light on dinosaur development.

FOSSIL OR ORIGINAL SHELL? According to Dr. Kenneth Carpenter of the Denver Museum, most dinosaur eggshells still have the original shell, not a fossilized replica, "The slightest change in the calcite making up the shell destroys the very fine detail that can be seen with the scanning electron microscope. Amino acids have also been recovered that are very similar to those found in modern bird eggshell."

RECENT FINDS About 10 large dinosaur eggs (plus 3 egg impressions) were found 1999 in southwestern France (near Albas, in the foothills of the Pyrenee Mountains). No bone fossils were found. The eggs had been buried in two layers in the sand. No one knows what type of dinosaur the eggs were.

Much larger egg sites have been found nearby, in northeastern Spain near Tremp, where hundreds of thousands of eggs (of both sauropods and theropods) have been found. Other huge dinosaur eggs sites have been found in Argentina and China.

NESTS

Fossils of dinosaurs' burrows and nests can reveal a lot about their behavior. Nests vary from simple pits dug into the Many Maiasaura nests have been earth or sand to more complicated nests found in Montana, USA; nests, eggs, constructed with mud rims. They may hatchinglings, juveniles, and adults were found in one area. This fossil appear in large groups or all alone. The evidence indicates a high level of nests and the clutches of eggs reveal parental care and a very social information about the dinosaur's dinosaur. nurturing behavior.

HOW DID THE GIANT SAUROPOD LAY THEIR EGGS One of the many unanswered questions about dinosaur reproduction is how the giant sauropods (like Apatosaurus, Diplodocus, and Brachiosaurus) laid their eggs without breaking them. Even if the sauropod squatted while laying eggs, the eggs would be dropped from a height of roughly 8 feet (2.5 m). Some scientists have theorized that females may have had tube that extended from the body for laying eggs (some modern-day turtles have a tube like this).

SIZE OF THE DINOSAURS

Dinosaurs ranged in size from the size of a chicken to well over 100 feet long. Most dinosaurs were somewhere in the middle. The modern-day blue whale is the largest animal that ever lived - it is larger than any dinosaur was.

No one knows why some of the dinosaurs (and some other Mesozoic Era reptiles) got so huge and none do today. This is one of the most interesting unanswered questions in paleontology. There are a lot of theories, but some of them are pretty bizarre; none are generally accepted

LONGEST The longest dinosaurs were sauropods; they were gigantic, slow-moving, tiny-headed, cow-like plant-eaters from the late Jurassic and the Cretaceous period. They had very long necks which were useful for reaching wide (and tall) swatches of vegetation. The lengthy neck was counterbalanced by a massive tail. These sauropods are the largest land animals ever discovered: Supersaurus - 134 feet long (41 m) Argentinosaurus - 115-130 feet long (35-40 m); 80-100 metric tons Seismosaurus ("Earth-shaking lizard") - 120+ feet long (37 m); +80 tons Ultrasauros - 100+ feet long (30 m), +80 tons

Diplodocus - grew up to 90 feet long (28 m). Brachiosaurus - about 85 feet long (26 m), 40 feet tall, and weighed 70-80 tons.

The biggest carnivores were theropods from the Cretaceous period: Giganotosaurus carolinii - found in Patagonia, Argentina. 47 feet long (14 m), 8 tons in weight, and 12 feet tall (4 m). Tyrannosaurus rex - found in North America - 40- 50 feet long (12-15 m), 6 tons in weight. Carcharodontosaurus saharicus - (meaning shark- toothed lizard) found in in Morocco, Africa, by Paul Sereno. It was probably about 45 feet long and had 5 inch long teeth. Its skull (5 feet 4 inches) is larger than T. rex's, but it had a tiny brain cavity (half the size of T. rex's).

TALLEST The tallest dinosaurs were brachiosaurid sauropods; they had front legs that were longer than their back legs and had a giraffe-like stance. They were gigantic, slow moving, tiny-headed, cow-like plant-eaters from the late Jurassic and the Cretaceous period. They had very long necks which were held upright and were useful for reaching wide (and tall) swatches of vegetation. The lengthy neck was counterbalanced by a massive tail. These sauropods are among the largest land animals ever discovered: Sauroposeidon, a newly-found brachiosaurid from Oklahoma, +60 tons, 60 feet tall. Ultrasauros - 100+ feet long (30 m), +80 tons, +40 ft tall Brachiosaurus - about 85 feet long (26 m), 40 feet tall, and weighed 70-80 tons.

SMALLEST Small fossils are found less easily than large fossils. Also, when small animals die, they are likely to be eaten, perhaps whole, by larger animals. The smallest dinosaurs yet discovered are: Compsognathus, a theropod (meat-eater) 2 feet (60 cm) long, from 145 million years ago. It was the size of a chicken and weighed about 6.5 pounds (3 kg). Saltopus - a 2 feet (60 cm) long insectivore (insect-eater) from about 200 million years ago. Lesothosaurus - a 3 feet (90 cm) long, fast running, plant-eater from Africa, 200 million years ago. INFRA- DINOSAUR TIME SIZE ORDER SUBORDER SOME GENERA ORDER FAMILY RANGE RANGE 2-3 feet Saltopodidae (leaping late Saltopus, Eoraptor (0.7-1 m) feet) Triassic long Staurikosaurids 6.5-10 feet late (Southern Cross Staurikosaurus (2-3 m) Herrerasauria Triassic lizards) long late 7-10 feet Herrerasaurids Triassic to (2-3 m) Herrerasaurus (Herrera lizards) early long or Jurassic more late 2-10 feet Coelophysids Triassic to Coelophysis, Saltopus (0.6-3 m) (hollow form) early long Jurassic 11.5-20 Ceratosaurids Early-Late CeratosaurusSyntarsus feet (3.5-6 (horned lizards) Cretaceous m) long 3-10 feet Podokesaurids (swift- Podokesaurus, Early-Late (1-3 m) footed lizards) Syntarsus Jurassic Ceratosauria long up to 36 Abelisaurids (Abel's Abelisaurus, Early-Late feet (11 m) lizard) Indosaurus Cretaceous long Noasaurids (lizards Late 8 feet (2.4 Noasaurus from NW Argentina) Cretaceous m) long late Segisauridae (Segi Segisaurus, Triassic to 20 feet (6 Canyon Arizona Dilophosaurus Early m) long lizards) Jurassic Late 4-8 feet Coelurids (hollow Coelurus, Jurassic to (1.2-2.4 tails) Ornitholestes Late m) long Cretaceous Dryptosaurids Late +20 feet (6 Dryptosaurus (wounding lizards) Cretaceous m) long late 2-3 feet Compsognathids Jurassic to Compsognathus (0.6-0.9 (pretty jaw) early m) long Cretaceous Oviraptors (egg Late 6 feet (1.8 Oviraptor thieves) Cretaceous m) long Late Caenagnathids Caenagnathus, Jurassic to 7 feet (2 (recent jawless) Microvenator Late m) long Cretaceous Avimimids (bird Late 5 feet (1.5 Avimimus mimics) Cretaceous m) long Late 11.5-19.5 Ornithomimids (bird Jurassic to Ornithomimus feet (3.5-6 mimics) Late m) long Cretaceous 11.6 feet Garudimimids Garudimimus, Mid-Late (3.5 m) (Garuda mimics) Harpymimus Cretaceous long Dinosaur Skeleton

SKELETAL FEATURES

Anatomically, dinosaurs have skeletal features that distinguish them from other archosaurs (crocodilians and pterosaurs). Dinosaurs have reduced fourth and fifth digits on their hands, their feet have three large toes, they have three or more vertebrae composing the sacrum (fused vertebrae by the hip), and have an open hip socket (a three-bone structure). This hip structure gives dinosaurs a posture that positions their legs under their bodies, unlike other reptiles, which have legs that sprawl out to the sides. For more information on T. rex's bones, click here.

HIPS Dinosaurs are classified by their hip structure, into the Order Saurischia (meaning lizard-hipped) and the Order Ornithischia (meaning bird-hipped). This division by pelvic (hip) structure is based on their evolutionary tree; early in the Triassic period, dinosaurs branched into these two groups from their ancestor, thecodonts. Saurischians

Ornithischians

SKULL The dinosaurs were diapsids (as are all reptiles except turtles), animals that had two extra holes in the sides of their skulls.

Some Dinosaur Skeletons:

Tyrannosaurus Triceratops Stegosaurus Skeleton rex Skeleton Brachiosaurus Skeleton A plant-eating The king of the Skeleton See the bones of this dinosaur with dinosaurs; a huge huge, plated plant- three horns and a meat-eater. Brachiosaurus was frill on its head. a tall, long-necked eater. plant-eater.

DINOSAUR TAILS

Most dinosaurs had large tails that probably had multiple uses, including acting as a:

Counterbalance - most dinosaur tails counterbalanced a long neck or a large, heavy head. Until a few years ago, people thought that dinosaurs dragged their tails on the ground, serving to do little but making locomotion difficult. This seemed pointless and ignored the fact that the large mass at the front of the dinosaur's body (neck and head) had to be counterbalanced or else the animal would tip over!

Tripod leg - The tails of some dinosaurs could be useful in attaining a tripod stance, which was probably used to forage very tall vegetation and for mating.

Help in turning quickly - Some dinosaurs needed to run speedily and to be able to turn quickly, either to catch prey or avoid predators. In order to turn quickly while running, the tail's movement can shift the runner's direction, allowing swift turns.

Bludgeon for protection - Ankylosaurids (like Euoplocephalus and Ankylosaurus) had bony nodules at the end of their tails that could easily have been used for defense, which would have been useful for these lumbering, plated grazers. Also, some theropods, like Shunosaurus, Omeisaurus and maybe Mamenchisaurus had tail clubs for protection. Whip for protection - In 1961, the British zoologist R. McNeill Alexander proposed the idea that some sauropods may have used their massive tails as a whip to lash at their attackers. This theory seems unlikely given the amount of physiological damage to tail tissue that would be caused by the sudden acceleration near the end of the tail (and the deceleration upon impact). Also, the large sauropods probably grazed on tree leaves, giving them no room to whip their tail around without hitting tree trunks and getting severe tail damage. In addition, the amount of time to get a nerve message from the head to the base of the tail (a distance of up to 50 feet, 15 m) would delay the attack considerably. Nerve impulses in humans travel at around 3 - 4 meters/second. If dinosaurs could match this rate of transmission, the time for a nerve impulse to travel from the head to the base of the tail would be about 4 - 5 seconds. Add to this the time to start the whip-like motion and the swift meat-eater would probably already have taken a big bite of Diplodocus. Prehensile appendage - Some people theorize that some dinosaur tails may have been prehensile, able to manipulate objects. The tails may have been used to build nests, move vegetation, etc., much as an elephant's trunk works.

DINOSAUR TEETH

Looking at an animal's teeth can give you a lot of information on how it lived. Dinosaur teeth can tell you a lot about the animal, including the type of food that it ate, how it obtained that food, and how much further digestion was required (did it chew its food, crush it, or just wolf it down?).

Teeth are harder than bone and therefore fossilize more readily than bones. Many fossilized dinosaur teeth have been found. Some species of dinosaurs (like Cardiodon, Deinodon, and Trachodon) are known only from fossilized teeth.

The number of teeth that dinosaurs had varied widely. Some, like Gallimimus and Ornithomimus, had no teeth. T. rex had 50 to 60 thick, conical teeth. The dinosaurs with the most teeth were the hadrosaurs (the duck-billed dinosaurs), which had up to 960 cheek teeth.

Dinosaurs had replaceable teeth; when a tooth was lost or broken, another one grew in to take its place.

SAURISCHIANS:

•Sauropods: The plant-eating sauropods (like Apatosaurus, Brachiosaurus, Diplodocus, Supersaurus, etc.) had peg-like or spoon-shaped teeth for stripping foliage but not for chewing. The tough plant material was digested in their huge guts, possibly in fermentation chambers, and frequently with the aid of gastroliths (gizzard stones, which were stones that the animal swallowed) that helped to grind up the leaves and twigs.

•Theropods: Theropods (like T. rex, Giganotosaurus, Carcharodontosaurus, Allosaurus, Spinosaurus, etc.) were meat-eaters that had sharp, pointed teeth for tearing flesh and/or crushing bones. A recent discovery of a Tyrannosaurus rex coprolite (fossilized feces) containing crushed bone indicates that T. rex did indeed crush its food with its strong teeth and powerful jaws.

ORNITHISCHIANS: The herbivorous (plant-eating) Ornithischians and some prosauropods had varied teeth, but mostly had horny beaks and many blunt, leaf-like cheek teeth for nipping and sometimes chewing tough vegetation.

•Stegosaurids: Stegosaurids (like Stegosaurus and Kentrosaurus) had leaf-shaped teeth.

•Hadrosaurs (the duck-billed dinosaurs which included Maiasaura, Parasaurolophus, Edmontosaurus, Lambeosaurus, etc.) had about 960 self-sharpening cheek teeth. They had more teeth than any other dinosaurs.

•Iguanodontids: (like Iguanodon, Ouranosaurus, and Probactrosaurus) had teeth similar to those of modern-day iguanas. The rounded, notched crown of the teeth were curved.

•Heterodontosaurus was a small Ornithischian dinosaur that had three different kinds of teeth (hence its name) and a beak. The sharp, cutting front, upper teeth were used for biting against the horny beak, the cheek teeth were for grinding food, and it also had two pairs of long, canine-like teeth that fit into sockets.

•Ceratopsians , like Triceratops, Styracosaurus, Monoclonius, and others, had toothless beaks that were used to gather their food and many flat cheek teeth which were used to chew tough, fibrous plant material.

•Most dinosaurs, like the Ankylosaurs (which included Ankylosaurus, Sauropelta, Euoplocephalus, etc.), could not chew their food and might have had large fermentation chambers in which the tough plant fibers were digested. Ankylosaurs had teeth that were shaped like a hand with the fingers together.

•Ornithomimids (like Ornithomimus, Ansermimus, Gallimimus, and Struthiomimus) had no teeth, only beaks, with which they ate plants, insects, and small animals.

First Dinosaur Fossil Discoveries Go to a printable version of this page

The first 3 dinosaur fossils led to the recognition of a new group of animals, the dinosaurs. The first nearly-complete dinosaur skeleton in New Jersey spurs modern paleontology.

People have been finding dinosaur fossils for hundreds of years, probably even thousands of years. The Greeks and Romans may have found fossils, giving rise to their many ogre and griffin legends. There are references to "dragon" bones found in Wucheng, Sichuan, China (written by Chang Qu) over 2,000 years ago; these were probably dinosaur fossils.

Much later, in 1676, a huge thigh bone (femur) was found in England by Reverend Plot. It was thought that the bone belonged to a "giant," but was probably from a dinosaur. A report of this find was published by R. Brookes in 1763.

The First Dinosaur Fossil Scientifically Described The first dinosaur to be described scientifically was Megalosaurus. This genus was named in 1824, by William Buckland; Gideon Mantell (not Ferdinand August von Ritgen) assigned the scientific type species name, Megalosaurus bucklandii. Buckland (1784-1856) was a British fossil hunter and clergyman who discovered collected fossils. (Note: the first dinosaur found was Iguanodon, but it was named and described later than Megalodon.)

It was the first dinosaur ever described scientifically and first theropod dinosaur discovered (this is all in hindsight, because the dinosaurs had not yet been recognized as a separate taxonomic group - the word dinosaur hadn't even been invented yet).

The first dinosaur models (life size and made of concrete) were made by Benjamin Waterhouse Hawkins of England in 1854. The first dinosaur used for amusement was a life-size model of an Iguanodon (made by Hawkins) that was used to house a dinner party for scientists (including Richard Owen) at a major exhibition. The invitations to the party were sent on fake pterodactyl wings. The party took place in London, England, in 1854

Other Early Dinosaur Finds

Gideon A. Mantell (1790-1852) was another early British fossil hunter. He described and named Iguanodon, a duck- billed plant-eater (1825); Iguanodon's teeth and a few bones were found in 1822,

IGUANODON perhaps by his wife, Mrs. Mary Mantell in HYLAEOSAURUS Sussex, (southern) England. Gideon Mantell also named Hylaeosaurus, an armoured plant-eater (1833) , and others.

The Name "Dinosauria" Sir Richard Owen (1804-1892) was a pioneering British comparative anatomist who coined the term dinosauria (from the Greek "deinos" meaning fearfully great, and "sauros" meaning lizard), recognizing them as a suborder of large, extinct reptiles in 1842.

He had noticed that a group of fossils (which included remains of Megalosaurus, Iguanodon, and Hylaeosaurus) had certain characteristics in common, including:

Column-like legs (instead of the sprawling legs that other reptiles have) Five fused vertebrae fused to the pelvic girdle.

Owen presented dinosaurs as a separate taxonomic group in order to bolster his arguments against the newly proposed theory of evolution (although Darwin's "Origin of the Species" wasn't published until 1859, the basic ideas of evolution were known, but its mechanisms, including natural selection, were not). Ironically, his work actually helped support the evolutionists arguments.

This new taxonomic name, Dinosauria, and new group of reptiles was only the beginning of a great scientific exploration. Since Owen's time, about 330 dinosaur genera have been described. Every few months (sometimes every few weeks), a new species is unearthed (for recent finds, see Dino News). Paleontologists have varying estimates of how many dinosaur genera existed during the Mesozoic Era; estimates range from about 1,000 to over 10,000. Whatever this number really is, there are a lot of new dinosaurs left to discover! The First Nearly-Complete Dinosaur Skeleton and First American Dinosaur The first dinosaur fossil found in the US was a thigh bone found by Dr. Caspar Wistar, in Gloucester County, New Jersey, in 1787 (it has since been lost, but more fossils were later found in the area).

In 1800 in Massachusetts, USA, Pliny Moody found 1-foot (31 cm) long fossilized footprints at his farm that were thought by Harvard and Yale scholars to be from "Noah's Raven." Many other dinosaur footprints were been found in New England stone quarries in the early 1800's, but they were thought to be unimportant and were blown up in the quarrying process. Other A Hadrosaur footprint. fragmentary dinosaur bones and tracks were unearthed at this time in Connecticut Valley, Massachusetts. The first nearly-complete dinosaur skeleton was discovered by William Parker Foulke. Foulke had heard of a discovery made by workmen in a Cretaceous marl (a crumbly type of soil) pit on the John E. Hopkins farm in Haddonfield, New Jersey beginning in 1838. Foulke heard of the discovery and recognized its importance in 1858. Unfortunately, some of the bones had already been removed by workmen. The skull-less dinosaur was excavated and named by US anatomist Joseph Leidy who named it Hadrosaurus fouki (meaning "Foulke's big lizard"). It was a duck-billed dinosaur (but it is now a doubtful genus because there is so little fossil information about it). The "Haddonfield Hadrosaurus" is on display at the Philadelphia Academy of Natural Sciences.

Leidy's analysis of this Hadrosaur skeleton was thorough; from its anatomy, he wrote imaginitively about the dinosaur's way of life and its death. Leidy wrote, "Hadrosaurus was most probably amphibious; and though its remains were obtained from a marine deposit, the rarity of them in the latter leads us to suppose that those in our possession had been carried down the current of a river, upon whose banks the animals lived." (Quoted from J. Leidy, Account of the Remains of a Fossil Reptile Recently Discovered at Haddonfield, New Jersey. Proceedings Academy of Natural Sciences, Philadelphia, Dec. 14, 1858 pp.1-16.)

This study influenced the popular image of dinosaurs and dinosaur science for years. This beautiful skeleton made dinosaurs come to life in peoples' imaginations and spurred generations of paleontologists.

Tyrannosaurus rex the "Tyrant lizard king"

T. rex was a huge meat-eating dinosaur that lived during the late Cretaceous period, about 85 million to 65 million years ago. T. rex lived in a humid, semi-tropical environment, in open forests with nearby rivers and in coastal forested swamps. The seasons were mild.

Until recently, Tyrannosaurus rex was the biggest known carnivorous dinosaur; Giganotosaurus and Carcharodontosaurus are slightly bigger.

ANATOMY Tyrannosaurus rex was a fierce predator that walked on two powerful legs. This meat-eater had a huge head with large, pointed, replaceable teeth and well-developed jaw muscles. It had tiny arms, each with two fingers. Each bird-like foot had three large toes, all equipped with claws (plus a little dewclaw on a tiny, vestigial fourth toe). T. rex had a slim, stiff, pointed tail that provided balance and allowed quick turns while running. T. rex's neck was short and muscular. Its body was solidly built but its bones were hollow.

SIZE Tyrannosaurus rex was up to 40 feet (12.4 m) long, about 15 to 20 feet (4.6 to 6 m) tall. The arms were only about 3 feet (1 m) long. Tyrannosaurus rex was roughly 5 to 7 tons in weight.

The enormous skull was about 5 feet (1.5 m) long. The eye sockets in the skull are 4 inches (10.2 cm) across; the eyeballs would have been about 3 inches (7.6 cm) in diameter.

T. rex left footprints 1.55 feet (46 cm) long (although its feet were much longer, about 3.3 feet (1 m) long; T. rex, like other dinosaurs, walked on its toes). It had a stride length of up to 12 to 15 feet (3.7- 4.6 m). T. rex may have run at up to 15 mph (24 kph).

TEETH AND JAWS

T. rex's jaws were up to 4 feet (1.2 m) long and had 50 to 60 thick, conical, bone-crunching teeth that ranged in size from very small to over 9 inches (23 cm) long. Adult had a variety of sizes of teeth in their jaws at one time, as teeth were broken and new (smaller) ones grew in to replace them. One T. rex was found with some teeth up to 13 inch (33 cm) long. T. rex could eat up to 500 pounds (230 kg) of meat and bones in one bite!

Tyrannosaurus rex had a wrap-around overbite; when T. rex closed its mouth, the upper parts of the lower jaw's teeth fit inside the upper teeth.

SKIN Fossilized specimens of T. rex's rough, scaly skin have been found. It was bumpy, like an alligator's skin, and has been described as a "lightly pebbled skin."

HABITAT AND DISTRIBUTION Tyrannosaurus rex probably lived in forests, where its prey (plant- eating dinosaurs) could find plenty of food. T. rex fossils have been found in western North America and Mongolia.

SENSES Sight: T. rex had large visual lobes in its brain that processed visual information. T. rex also had depth perception (since both eyes faced forwards on the front of its skull, and not placed on the sides), but it was not the only dinosaur that had depth perception. In general, predators (hunters) ofter have depth perception to help them hunt their prey. Animals that are hunted (like the plant-eating dinosaurs) usually have eyes located on the sides of their head (having no depth perception); this lets them see predators approaching from both sides.

Smell: T. rex's brain had a very large area in the brain for processing odors.

TAIL Tyrannosaurus had a stiff, pointed tail (like other Tetanurans [meaning "stiff tail"]). The tail was used as a counterbalance for its enormous head, for agility and for making quick turns.

The rear part of the tail was stiffened by interlocking vertebral zygopophyses (interlocking bony structures projecting forwards and backwards from the neural arches, interlocking one vertebra into another).

OTHER HUGE MEAT-EATING DINOSAURS Although not the biggest meat-eating dinosaur ever discovered, Tyrannosaurus rex was certainly one of the largest terrestrial carnivores of all time. The recently discovered Giganotosaurus carolinii and Carcharodontosaurus may have been even more enormous. SIZE COMPARISONS

Why T. rex's weren't great boxers.

K-3 level Triceratops Printout to Color Labeled Triceratops Printout Triceratops Triceratops Skeleton Printout Color Triceratops Online horridus Triceratops Questions and "Horrible Three-horned Face" Answers Triceratops Fact Sheet

ANATOMY Triceratops was a rhinoceros-like 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). One short horn above its parrot-like beak and two longer horns (over 3 feet or 1 m long) above its eyes probably provided protection from predators. The horns were possibly used in mating rivalry and rituals. It had a large skull, up to 10 feet (3 m) long, one of the largest skulls of any land animal ever discovered. Its head was nearly one-third as long as its body. Triceratops hatched from eggs.

Triceratops was about 30 feet long (9 m), 10 feet tall (3 m), and weighed up to 6-12 tons. It had a short, pointed tail, a bulky body, column-like legs with hoof-like claws, and a bony neck frill rimmed with bony bumps. It had a parrot-like beak, many cheek teeth, and powerful jaws.

WHEN TRICERATOPS LIVED Triceratops lived in the late Cretaceous period, about 72 to 65 million years ago, toward the end of the Mesozoic, the Age of Reptiles. It was among the last of the dinosaur species to evolve before the Cretaceous-Tertiary extinction 65 million years ago. Among the contemporaries of Triceratops were Tyrannosaurus rex (which probably preyed upon Triceratops), Ankylosaurus (an armoured herbivore), Corythosaurus (a crested dinosaur), and Dryptosaurus (a meat-eating dinosaur).

BEHAVIOR Triceratops was probably a herding animal, like the other Ceratopsians. This hypothesis is supported by the finding of bone beds, large deposits of bones of the same species in an area.

When threatened by predators, Triceratops probably charged into its enemy like the modern-day rhinoceros does. This was probably a very effective defense.

REPRODUCTION No one knows how Triceratops reproduced or raised their young, except that they probably hatched from eggs.

INTELLIGENCE Triceratops was a ceratopsian, whose intelligence (as measured by its relative brain to body weight, or EQ) was intermediate among the dinosaurs.

DIET, TEETH, AND ITS POSITION IN THE FOOD CHAIN

Triceratops was an herbivore, a plant eater (a primary consumer). It probably ate cycads and other low-lying plants with its tough beak. Triceratops could chew well with its cheek teeth (like other Ceratopsians, but unlike most other dinosaurs). Triceratops was hunted and eaten by T. rex. Coprolite (fossilized feces) from a T. rex was recently found in Saskatchewan, Canada by a team led by Karen Chin. This 65 million year old specimen contains chunks of bones from an herbivorous (plant-eating) dinosaur which was eaten by the T. rex. This bone fragment is perhaps part of the head frill of aTriceratops.

LOCOMOTION Triceratops walked on four short legs; it was a relatively slow dinosaur. Dinosaur speeds are estimated using their morphology (characteristics like leg length and estimated body mass) and fossilized trackways.

LOCATIONS AND DISCOVERY OF FOSSILS Many Triceratops fossils have been found, mostly in western Canada and the western United States. Paleontologist Othniel Marsh named Triceratops in 1889 - from a fossil found near Denver, Colorado, USA. At first this fossil was mistakenly identified as an extinct species of buffalo. The first Triceratops skull was found in 1888 by John Bell Hatcher. About about 50 Triceratops skulls and some partial skeletons have been found.

CLASSIFICATION Triceratops was a late Ornithischian dinosaur, the order of bird-hipped, herbivorous dinosaurs. It was a member of the suborder Marginocephalia, and the family of large, horned, herding herbivores, the Ceratopsians. The ceratopsians were one of the last major group of dinosaurs to evolve, and include Psittacosaurus, Leptoceratops, Pachyrhinosaurus, Montanoceratops, Chasmosaurus, Centrosaurus, Triceratops, Styracosaurus, Protoceratops, and others.

Kingdom Animalia (animals) Phylum Chordata (having a hollow nerve chord ending in a brain) Class Archosauria (diapsids with socket-set teeth, etc.) Order Ornithischia - bird-hipped dinosaurs (plant-eaters) Suborder Marginocephalia - Infraorder Ceratopsia (also called Ceratopia) Family Ceratopsidae Genus Triceratops SpeciesT. horridus (type species: Marsh, 1889)

There is some disagreement about how many species of Triceratops have been found. Some paleontologists (notably Ostrom and Welnhoffer, 1990) believe there is one species, Triceratops horridus. Others believe that there are two (C. Forster, 1996) or more species, including: Triceratops horridus, Triceratops prorsus, Triceratops albertensis, Triceratops ingens, Triceratops alticornis, and perhaps others.

TRICERATOPS ACTIVITIES AND PRINTOUTS

Print out a K-3 level Triceratops info page to color! A Triceratops printout with information and a labelled diagram. A Triceratops skeleton printout. A first-grade level Triceratops addition activity print-out. Triceratops Find It! Quiz to print out for grades 2 to 3. A print-out quiz about Triceratops - Unscramble the answers and see how much you know about Triceratops! For grades 2-3. A Triceratops math/coloring activity - For second graders. Do 1-digit addition problems to color a Triceratops scene. A T. rex and Triceratops Activity print-out for beginning readers (advanced first graders to second graders). Students read and follow the directions to complete a Cretaceous scene. An on-line quiz about Triceratops - answer the questions and you will unscramble the picture of Triceratops! On-line for grades 2-4. Triceratops Fact Sheet with a printable version.

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AGE An age is a unit of geological time which is distinguished by AGATHAUMAS some feature (like an Ice Age). (pronounced ag-ah-THAW-mas ) Agathaumas An age is shorter than epoch, (meaning "great wonder") was a ceratopsid usually lasting from a few resembling Triceratops. This horned plant-eater millions of years to about a dates from the late Cretaceous period. Fossils (only hundred million years. a few bones from the hip area) have been found in western North America. It was named by paleontologist Cope in 1872. The type species is A. sylvestris. This genus is a nomen dubium. AGROSAURUS (pronounced AG-roh-SAWR-us) Agrosaurus (meaning "wild country AGILISAURUS lizard") was an ornithischian dinosaur, a (pronounced AJ-il-eh-SAWR-us) primitive prosauropod about 6.5-10 feet Agilisaurus (meaning "agile lizard") was a (2-3 m) long, weighing perhaps 18-30 lightly-built dinosaur that was about 3.5-4 pounds (40-70 kg). This small bipedal feet (1.2-1.7 m) long and weighed roughly plant-eater had a long tail, short arms, and 40 kg. This plant-eater lived during the lived during the late Triassic period, about middle Jurassic period, about 170 million 225-213 million years ago. It was thought years ago. It was perhaps a to be the first fossil found in Australia, but hypsilophodontid. A nearly complete has since been found to a mislabeled fossil skeleton was found in China. Agilisaurus from Britain (Wales). Only a few bones was named by Peng in 1990. The type were found. Agrosaurus was named by species is A. louderbecki. Seeley in 1891. The type species is A. macgillvrayi, but Agrosaurus is a nomen dubium and is probably the same as Thecodontosaurus antiquus.

ALAMOSAURUS (pronounced Al-uh-moe-SAWR-us) Alamosaurus (meaning "Ojo Alamo [New ALBERTOSAURUS Mexico] lizard" ) was a long-necked, whip- (pronounced al-BUR-toh-SAWR-us) tailed dinosaur about 69 feet (21 m) long Albertosaurus was a large, meat-eating and weighed perhaps 33 tons (30000 kg). It dinosaur from the late Cretaceous period. was a quadrupedal, plant-eater from New It was a theropod related to T. rex. Mexico, Texas, and Utah, USA during the Albertosaurus was about 8.6 m long and late Cretaceous period, about 73 million to weighed about 2500 kg. The type species 65 million years ago. It was a sauropod and is A. sarcophagus. a Titanosaurid that may have had some body armor. It was named by Gilmore in 1922. The type species is A. sanjuanensis. ALGOASAURUS (pronounced al-GOH-a-SAWR-us) Algoasaurus (meaning "Algoa Bay ALECTROSAURUS (South Africa) lizard") is doubtful genus (pronounced ah-LECK-troh-SAWR-us) of dinosaurs; it is known from only a Alectrosaurus [meaning "Alectra's lizard," few bones found in Africa. This long- Alectra was one of the furies in classical necked, long-tailed plant-eater (a mythology] was a huge, bipedal, meat- neosauropod and perhaps a titanosaurid) eating dinosaur from the late Cretaceous was about 30 ft (9 m) long. It lived period, about 98 million to 88 million years during the early Cretaceous period, ago. It was a tyrannosaurid, a theropod about 145-135 million years ago. The related to T. rex, but it had larger arms and type species is A. bauri. Algoasaurus claws and very long jaws with many teeth. was named by the paleontologist Broom Unlike most tyrannosaurids, its skull was in 1904. smooth on top. It was about 25-30 feet (8-9 m) long and weighed perhaps 1.5 tons. It had powerful legs, tiny arms, and a stiff, pointed tail. Partial skeletons have been found in the Gobi Desert in Mongolia. Alectrosaurus was named by paleontologist C. W. Gilmore in 1933. The type species is A. olseni.

ALIORAMUS (pronounced AL-ee-uh-RAY-mus) ALIWALIA Alioramus, meaning "different branch," (pronounced ahl-ih-WAHL-ee-ah) was a large, bipedal, meat-eating dinosaur Aliwalia (named for Aliwal North, South from the late Cretaceous period, about 73 Africa) was a carnivorous dinosaur million to 65 million years ago. It was a known from only a few bones found in tyrannosaurid theropod about 16-20 feet (5- south Africa. This meat-eater (a 6 m) long, perhaps weighing up to 1 ton. It theropod) was about 25 ft (8 m) long and had 6 tiny horns on its snout; four in a row weighed about 1500 kg. It lived during on the lower snout plus a horizontal pair the late Triassic period, about 145-135 near the eyes. It had powerful legs, tiny million years ago. The type species is A. arms, and a stiff, pointed tail. It had more rex. Aliwalia was named by the teeth and a longer skull than other paleontologist Galton in 1985. The type tyrannosaurids. A single, fragmentary species is A. rex. skeleton was found in Mongolia. Alioramus was named by Kurzanov in 1976. The type species is A. remotus.

ALLOPATRIC SPECIATION ALLIGATOR Allopatric speciation is the formation of new species after Alligators are large a population has been separated geographically. Over reptiles. Primitive time, the two isolated populations diverge genetically. alligators evolved during Allopatric speciation is probably the major mode of the late Triassic period. speciation (the formation of new species). Compare with parapatric speciation and sympatry.

ALLOPATRY ALLOSAURUS Allopatry means occupying (pronounced Al-oh-SAWR-us) Allosaurus, meaning different geographic "different lizard," was a huge, meat-eating dinosaur from locations. Compare with the late Jurassic period, about 154 million to 144 million parapatry and sympatry. years ago. It was a theropod that lived in what is now the western United States. It was about 10.5 m long. The type species is A. fragilis. ALPHADON (pronounced AL-fa-don) Alphadon (meaning "first tooth") was a metatherian, ALOCODON primitive marsupial. It was not a dinosaur, (pronounced a-LOK-oh-don) Alocodon but lived with the dinosaurs. Alphadon (meaning "furrowed tooth") is doubtful was a small omnivore, eating fruit, genus of dinosaurs; it is known from only insects, and small animals. It was about 1 a single tooth. Alocodon was a small, feet (30 cm) long. This tree-dweller had plant-eating dinosaur of unknown length, opposable toes and a prehensile tail which perhaps about about 3 feet (1 m) long. It it may have used to climb trees. It lived in was an ornithischian from Europe North America (Alberta, Canada to New (Portugal) during the late Jurassic period, Mexico, USA) during the late Cretaceous about 164 million years ago. The type period, about 70 million years ago. The species is A. kuehni. Alocodon was named type species is A. marshi. Alphadon was by the paleontologist Thulborn in 1973. named by the paleontologist Simpson in 1929. Classification: Subclass Prototheria, Order Pantotheria, Infraclass Metatheria, Genus Alphadon. ALTIRHINUS (pronounced al-ti-RINE-us) Altirhinus (meaning "high snout") was an iguanodontid, a plant-eating dinosaur about about 23-26 feet (7-8 m) long. Altirhinus had a tall beak on its rounded snout and a spiked thumb on each hand. ALTICAMELUS This big-nosed dinosaur may have had a Alticamelus (meaning "tall camel") is the good sense of smell. It walked on two old name of Aepycamelus. It was a long legs but could also eat on all four prehistoric camel that lived from the middle imbs - the arms were a bit smaller than through late Miocene. This giraffe-like the legs. It was an ornithischian from early camel was about 10 ft (3 m) tall at the Mongolia during the early Cretaceous head; it had a small back hump and a short period. The type species is A. kurzanovi. tail. It had very long legs, and small hooves Altirhinus was named by the on its two toes and broad pads. It probably paleontologist David Norman in 1998. moved in a manner similar to modern-day Altirhinus used to be known as camels. Fossils of this mammal have been Iguanodon bernissartensis, found in Colorado, USA. (Rozhdestvensky, 1952). ALTISPINAX ALVAREZ, LUIS (pronounced AL-tee-SPY-nax) Altispinax Luis Alvarez (1911-1988) was a (meaning "high spine") is doubtful genus of physicist who, with his son Walter dinosaurs; it is known from only a single Alvarez (a geologist), hypothesized that tooth. The vertebral material originally the a huge asteroid hit Earth the Earth 65 found (which gave this dinosaur its name) million years ago, causing a mass has been assigned the name Becklespinax. extinction. The Alvarez Theory of Altispinax was a large meat-eating dinosaur Extinction is widely accepted. Luis of unknown length, perhaps about about 30 Alvarez received a Nobel Prize in feet (9 m) long, weighing roughly 1000 kg. physics (1968) for his work on It was a theropod, a bipedal, meat-eating, subatomic particles. stiff-tailed predator from Europe (England) during the early Cretaceous period, about 123-119 million years ago. The type species is A. dunkeri. Altispinax was named by the paleontologist von Huene in 1923. ALVAREZSAURUS (pronounced Al-vuh-rez-SAWR-us) Alvarezsaurus was a small, lightly-built, bird-like, bipedal theropod (a meat-eating dinosaur) that ALVAREZ THEORY OF was about 6 feet (2 m) long, weighing roughly 20 EXTINCTION kg. This fast runner had very long legs, long feet, This theory is that a large asteroid, very short arms, a long, s-shaped neck, and an meteor, or comet hit the Earth 65 extremely long, thin, flat tail. The tail was over million years ago, causing huge half of the dinosaur's length. It had no ridges on atmospheric and geologic its back, like most other theropods. It lived during disruptions, leading to a mass the late Cretaceous period, 80 million years ago, extinction which killed the in what is now Argentina. It and the family of dinosaurs and many other species. Alvarezsaurids were named for the historian Don Gregorio Alvarez by José Bonaparte in 1991. The type species is A. calvoi.

ALXASAURUS ALWALKERIA (pronounced AWL-shah-SAWR-us) (pronounced al-wah-KEER-ee-a) Alxasaurus (meaning "Alxa [Desert of Alwalkeria was a small, early theropod (a Inner Mongolia] lizard") was an advanced bipedal, meat-eating dinosaur). It lived theropod (a meat-eating dinosaur) that was during the late Triassic period, roughly about 11.5-13 feet (3.5-4 m) long and 220 million years ago. An incomplete weighed about 800-900 pounds (350 to fossil was found in what is now India. It 400 kg). This bipedal carnivore had long was named by Chatterjee and Creisler in legs with clawed feet, relatively long 1994, honoring the British vertebrate arms, a long, s-shaped neck, a toothless paleontologist Alick D. Walker. The type beak, and a short tail. Alxasaurus was the species is A. maleriensis. most primitive therizinosauroid (bird-like asian theropods with unusual feet). It lived during the Cretaceous period, about 99 million years ago, in what is now Mongolia. It was named by paleontologists D. A. Russell and Dong in 1995. The type species is A. elesitaiensis.

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ANASAZISAURUS (pronounced ahn-ah-SAH-zee-SAWR-us) Anasazisaurus ANAPSID (meaning "Anasazi lizard") was a plant-eating dinosaur (pronounced an-AP-sid) very similar to Kritosaurus. This hadrosaur was about 33 Anapsids include the turtles ft (10 m) long and lived during the late Cretaceous and their extinct kin. They period. Only a skull was found, in New Mexico, USA. are distinguished by having Anasazisaurus was named by Hunt and Lucas in 1993. no holes in the sides of The type species is A. horneri. their skulls.

ANATOMY Anatomy is the study of ANATOSAURUS structure of organisms. (pronounced uh-NAT-uh-SAWR-us) Anatosaurus (meaning Anatomists are scientists "duck lizard") is an obsolete name for Edmontosaurus, a who study anatomy. duck-billed dinosaur from the Cretaceous period. Anatosaurus was named by Lull and Wright in 1942; the type species is A. annectens. A. longiceps = Anatotitan longiceps.

ANCHICERATOPS (pronounced AN-key-SER-ah-tops) Anchiceratops (meaning "horn-near-face") ANATOTITAN was a Ceratopsid dinosaur from the late (pronounced un-NAT-uh-TYE-tan) Cretaceous period, about 73 million to 70 Anatotitan (meaning "giant duck") was million years ago. This plant-eater was 15-20 a large, duck-billed dinosaur up to 40 ft (4.5-6 m) long and weighed roughly 2470 feet (12 m) long, weighing roughly kg. Anchiceratops was a quadruped. It had a 7300 kg. This plant-eater lived during long, rectangular-shaped frill with scalloped the late-Cretaceous period, 70 million- edges and a big skull with two long, pointed 65 million years ago in what is now brow horns and a stubby snout horn. It is western North America. The type only known from 6 skulls found in Alberta, species is A. copei. Canada. This dinosaur was named by fossil hunter B. Brown in 1914. The type species is A. ornatus.

ANCHISAURIPUS (pronounced AN-key-SAWR-ip-us) ANCHISAURUS Anchisauripus is an ichnogenus of (pronounced AN-key-SAWR-us) dinosaur, a theropod dinosaur only known Anchisaurus (meaning "near lizard") was from fossilized, bipedal, three-toed a prosauropod from the early Jurassic footprints (roughly 4 to 7 inches long). This period, about 200 million to 188 million ichnogenus lived in what is now years ago. This plant-eater was 6.5 to 8 Connecticut, USA during the late Triassic feet (2 to 2.5 m) long and probably to early Jurassic period. It was named by R. weighed from 65-150 pounds (30-70 kg). S. Lull in 1904. It was a quadruped that could also walk on two legs. It had serrated, leaf-shaped teeth, a small head, a long neck, a long body, long, thin feet, and a long tail. Almost complete fossils have been found in Connecticut and Massachusetts, USA. This dinosaur was named by paleontologist O. Marsh in 1885. The type species is A. polyzelus. It is also known as Yaleosaurus.

ANDESAURUS (pronounced AN-di-SAWR-us) Andesaurus delgadoi was a 60-130? feet (18-40 m) long Titanosaurid sauropod that weighed roughly 12500 kg. It was an enormous, long-necked, ANDREWS, ROY C. long-tailed, quadrupedal, plant-eater from Roy Chapman Andrews (1884-1960) Argentina, South America during the was a US fossil hunter and director of the Cretaceous period, about 113 million to 91 American Museum of Natural History. million years ago. Its tail vertebrae, which Andrews led four expeditions to the were ever 2 feet (0.6 m) long, had ball and Mongolia's Gobi desert between 1922 socket joints (the same type of joint we and 1925. Many important finds were have in our hips). Andesaurus, meaning made on these expeditions, including "Andes mountain Lizard," was named by Protoceratops bones and eggs (the first Calvo & José Bonaparte in 1991. It is dinosaur eggs found!), and the new known from vertebrae, arm, and hip bones. dinosaurs Oviraptor, Pinacosaurus, Saurornithoides, and Velociraptor.

ANDREWSARCHUS (pronounced ANN-drew-SARK-us) Andrewsarchus (named for paleontologist Roy Chapman Andrews, who led the ANGATURAMA expedition on which it was found) was a (pronounced AHN-gah-two-RAH-ma) primitive, carnivorous mammal that lived Angaturama (meaning "noble one") was during the early Eocene Epoch, roughly 45 a meat-eating dinosaur, a spinosaurid million years ago. This giant creodont was theropod. It lived during the early heavily-built and wolf-like. It was about 13 Cretaceous period. Only a partial skull feet (4 m) long and had a skull over three was found, in N.E. Brazil. It was named feet (1 m) long; it was the largest creodont. It by Kellner and Campos in 1996. The walked on four short legs and had a long type species is A. limai. Angaturama be body, a long tail, and a long snout. It had the same as Irritator. large, sharp teeth and clawed feet. Flat cheek teeth were perhaps used to crush bones. Fossils have been found in Mongolia; they were first found in 1923 by Kan Chuen Pao. Andrewsarchus may be an ancestor of the whales.

ANGIOSPERMS ANHANGUERA (pronounced AN-gee-oh-sperms) Anhanguera santanae (meaning "old Angiosperms (meaning "covered seed") devil") was a pterosaur (not a dinosaur). are flowering plants. They produce seeds This Pterodactyloid had a skull 1.6 ft (50 enclosed in fruit (an ovary). They are the cm) long with a small crest on top of the dominant type of plant today; there are snout. It had small, widely-spaced teeth in over 250,000 species. Their flowers are the long, sturdy jaws. Anhanguera had an used in reproduction. Angiosperms estimated wingspan 13.6 feet (4.1 m). evolved about 140 million years ago, Fossils of this flying reptile were found in during the late Jurassic period, and were northeastern Brazil . This carnivore lived eaten by dinosaurs. They became the during the early Cretaceous period. dominant land plants about 100 million years ago (edging out conifers, a type of gymnosperm). Angiosperms are divided into the monocots (like corn) and dicots (like beans).

ANKYLOSAURS (pronounced AN-kye-loh-sawrs or ang-

ANKYLOSAURIDS KY-loh-sawrs) The ankylosaurs (pronounced AN-kye-loh-SAWR-ids or (ankylosauria) were a group (family) of ang-KY-loh-SAWR-ids) Ankylosaurids armoured, plant-eating, ornithischian were one division of the ankylosaurs, a dinosaurs from the mid-Jurassic to the late group of armoured, plant-eating, Cretaceous periods. The ankylosaurs are ornithischian dinosaurs with tail clubs divided into the Nodosaurids (having no and massive legs. Ankylosaurus and tail clubs, like Sauropelta) and Euoplocephalus were ankylosaurids. Ankylosaurids (with tail clubs, like Euoplocephalus).

ANKYLOSAURUS ANNING, MARY (pronounced AN-kye-loh-SAWR-us or ang- Mary Anning (1799-1847) was a British KY-loh-SAWR-us) Ankylosaurus (meaning fossil hunter who began finding fossils "fused lizard") was a heavily armoured as a child, and supported herself and her plant-eating, ornithischian dinosaur from the family by finding and selling fossils. late Cretaceous period. It was named by She lived on the southern coast of Barnum Brown in 1908. The type species is England, in Lyme Regis. Anning found A. magniventris. the first fossilized plesiosaur and Ichthyosaurus. She found many important fossils, including Pterodactylus, sharks, and many other reptiles and fish.

ANOMOEPUS ANODONTOSAURUS Anomoepus intermedius is a dinosaur (pronounced an-oh-DONT-oh-SAWR-us) known only from its fossilized tail Anodontosaurus (meaning "toothless lizard" prints; these prints are only a few was a small plant-eating dinosaur that actually inches long. This ichnogenus lived had teeth, but only in the back of the mouth. It during the Triassic period. is actually an ankylosaurid, Euoplocephalus Anomoepus was named by E. B. acutosquameus. It dates from the late Hitchcock in 1848. Fossils have been Cretaceous period, about 76-70 million years found in Holyoke, Massachusetts, ago. The type species is A. lambei. This and New Jersey, USA. doubtful genus was named by Sternberg in 1929.

ANOPLOSAURUS ANORBITA (pronounced an-OP-loh-SAWR-us) Anoplosaurus FENESTRA (meaning "no-weapon lizard" was a small iguanodontid An antorbital fenestra is a dinosaur from the early Cretaceous period, about 98 hole in the skull million years ago. This plant-eater had thumb spikes. A immediately in front of an very incomplete fossil was found in England. The type eye. This fenestra is species is A. curtonotus. This doubtful genus was named marks the diapsids. by British scientist Harry Govier Seeley in 1879.

ANSERIMIMUS (pronounced AN-ser-i-MIEM-us) Anserimimus (meaning "goose mimic" was an ornithomimid theropod dinosaur from the late Cretaceous period, about 75-70 million years ago. ANTARCTICA This 3 ft (1 m) long meat-eater was lightly built (weighing Antarctica is an icy about 62 kg), had long legs, short arms with long claws, a continent around the long tail, a long neck, and very few teeth. One skeleton South Pole. (without a skull) was found in Mongolia. The type species is A. planinychus. Anserimimus was named by Barsold in 1988.

ANTARCTOSAURUS Antarctosaurus (meaning "opposite-of-northern lizard") was a giant, long-necked, long-tailed, very ANTHOPHYTA small-headed, quadrupedal, plant-eating titanosaurid Anthophyta are flowering plants, sauropod from the late Cretaceous period, about 83 the largest group of plants million to 65 million years ago. It had a bulky body, (which includes the grasses). weak jaws, and had teeth only at the front of the The flowers are used in mouth. It was 60-100 feet (19-30 m) long and reproduction. They evolved weighed roughly 57900 kg. Its rear legs were much during the Cretaceous period. longer than the front legs. Incomplete fossils have been found in Argentina, Uruguay, and Chile, South America. Antarctosaurus was found in 1916 and named by paleontologist von Huene in 1929.

ANTIARCHI Antiarchs (the Antiarchi) were a type of (mosty) small placoderms that were abundant during mid- to late-Devonian. These armoured fish ranged from 8-12 inches (20-30 cm) long. Instead of the pectoral fins that other fish have, these unusual tetrapods had segmented "arms" that were covered by hard dermal bone, but these arms lacked an internal skeleton. Arm ANTRODEMUS muscles were attached to the interior of the (pronounced AN-truh-DEE-mus) dermal plates. The "arms" had two joints, at Antrodemus is an invalid name for the shoulder and at the elbow (2/3 the way Allosaurus. It was a huge, meat-eating down from the shoulder) and may have dinosaur from the late Jurassic period, allowed the fish to move in shallow water about 156 million to 135 million years or perhaps on land briefly. Antiarchi also ago. It was a theropod that lived in what differed from other placoderms in that most is now the western United States. placoderms had a flexible joint between the head and thorasic shields, but antiarchs lacked this joint, and the head and thorasic shield were fused together. Bothriolepis, which fed on organic-rich sediment, was a 20-30 cm long antiarch with auxillary lungs. Pterichthyodes was a 15 cm Antiarch from the mid-Devonian.

ANUROGNATHUS

(pronounced uh-NUR-ugh-NATH-us) Anurgnathus was a pterosaur, a flying reptile that ANURA had a 1 foot (30 cm) wide wingspan, deep, wide, Anura (or Salienta) is the clade of puffin-like jaws and a short tail. It probably ate frogs, toads, and their close fossil insects with its peg-like teeth. It lived during the relatives. Anura means "no tail," late Jurassic period in what is now Germany. It since these amphibians lose their was not a dinosaur, but a closely related reptile. It tail as an adult. The earliest anuran was named by Doederline in 1923. is Triadobatrachus, from the early Triassic period.

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APATODON (pronounced uh-PAT-uh-don) Apatodon APATOSAURUS is a doubtful genus; it is probably an (pronounced uh-PAT-uh-SAWR-us) Allosaurus. It was a huge, meat-eating Apatosaurus was a huge sauropod from the dinosaur from the late Jurassic period, Jurassic period. It was about 70 to 90 ft about 156 million to 135 million years (21-27 m) long and weighed roughly ago. It was a theropod that lived in what is 42500 kg. This quadrupedal plant-eater now the western United States. used to be known as Brontosaurus

AQUATILAVIPES APOMORPHY Aquatilavipes is an early bird known only from its An apomorphy is a new footprints, which are modern looking (not reptilian like genetic characteristic to a Archaeopteryx). It lived during the early Cretaceous clade. Feathers are an period, about 130 million years ago; these are the oldest- apomorphy for birds. known bird tracks. Fossil footprints have been found in Canada.

ARAGOSAURUS (pronounced AHR-ah-go-SAWR-us) ARALOSAURUS Aragosaurus (meaning "Aragón (Spain) (pronounced AR-a-lo-SAWR-us) lizard") was a large, quadrupedal plant- Aralosaurus (meaning "Aral Sea lizard") eating dinosaur that lived during the early was a plant-eating dinosaur that lived Cretaceous period, about 130-120 million during the late Cretaceous period, about years ago. This sauropod was about 60 ft 95-80 million years ago. This sauropod (18 m) long and weighed about 28000 kg. was about 30 ft (9 m) long, and weighed It had a long neck, a long powerful tail, a roughly 5000 kg. It had a toothless beak, a small head, and a bulky body. It was stiff tail, and a bulky body. A partial fossil similar to Camarasaurus. A partial fossil was found in Kazakhstan. It was named was found in Spain. It was named by Sanz, by Rozhdestvensky in 1968. The type Buscalioni, Casanovi and Santafe in 1987. species is A. tuberiferus. The type species is A. ischiatus. ARAUCANORAPTOR ARARIPEDACTYLUS Araucanoraptor (which means Araripedactylus was a pterosaur (not a "Argentinian Araucan thief") was a meat- dinosaur). This Pterodactyloid had a skull eating dinosaur with sickle-like toe claws. 1.6 ft (50 cm) long and an estimated It was about 8 ft (2.5 m) long. Fossils of wingspan 16 feet (4.8 m). Fossils of this this coelurosauris theropod were found in flying reptile were found in northeastern Argentina . Araucanoraptor lived during Brazil . This carnivore lived during the the late Cretaceous period, roughly 90 early Cretaceous period. Araripedactylus million years ago. Araucanoraptor was was described in 1971 by L.I. Price. named in 1997 by paleontologist F. Novas. The type species is A. argentinus.

ARCHAEOCETE ARCHAEOCERATOPS (pronounced AHR-kee-oh-SEAT) (pronounced AHR-kee-oh-SER-a-tops) Archaeocetes (meaning "ancient Archaeoceratops (meaning "ancient horned- whales") are early whales - whales that face") is the oldest-known ceratopsian lived during the Eocene period dinosaur. It lived during the early Cretaceous (roughly 55-34 million years ago) . period, about 95-80 million years ago. A Some archaeocetes include Pakicetus, partial skeleton was found in China. It was Ambulocetus, Basilosaurus, named by Dong and Azuma in 1996. The type Remingtonocetus, Dorudon, and other species is A. shimai. early whales, some of which had hind limbs.

ARCHAEORAPTOR Archaeoraptor liaoningensis (meaning "ancient robber from Liaoning [China]") is a newly-discovered dinosaur, which was recently found to be a fradulent fossil created by combining two separate fossils. ARCHAEOPTERYX This turkey-sized theropod was said to have (pronounced ark-ee-OP-ter-icks) lived about 120-140 million years ago. It Archaeopteryx (meaning "ancient supposedly had hollow bones, feathers, a wing") is a very old prehistoric bird long tail, and its shoulder girdle and breast dating from the Jurassic period, about bone were similar to those of modern birds, 150 million years ago. It had teeth, indicating that it may have been able to fly. feathers, three claws on each wing, a flat Fossils of this bipedal meat-eater were sternum (breastbone), and a long, bony found in Liaoning Province, China. tail.

ARCHAEORNITHOIDES (pronounced AHR-kee-OR-nith-OI-deez) ARCHAEORNIS Archaeornithoides (meaning "Archaeornis-like Archaeornis (meaning [dinosaur]") was a Coelurosaurid dinosaur about 3 ft (1 "ancient bird"), named in m) long, weighing roughly 2 kg. This bird-like, meat- 1917 by Petronievics and eating dinosaur had unserrated teeth. A partial skull of Woodward, is actually a juvenile Archaeornithoides was found in Mongolia. It Archaeopteryx (the Berlin dates from the late Cretaceous period. This advanced specimen). theropod was named by Elzanowski and Wellnhofer in 1992. The type species is A. deinosauricus.

ARCHAEORNITHOMIMUS ARCHAEOZAOIC or (pronounced AHR-kee-or-NITH-oh-MIME-us) ARCHEAN Archaeornithomimus (meaning "ancient bird The Archaeozoic (also called the mimic") was a small Coelurosaurid dinosaur Archean) was an eon of geologic about 3 ft (1 m) long, weighing roughly 20 kg. time during which the earliest life This bird-like, meat-eating dinosaur had three forms evolved. One celled fingers, which leads to questions about its being organisms, including blue-green an ornithomimid. A partial skull of a juvenile algae, archaeans, and bacteria appear Archaeornithoides was found in China. It dates in the sea. This began to free oxygen from the late Cretaceous period. This advanced into the atmosphere.The theropod was named by Russell in 1972. The Archaeozoic lasted from 3.9 to 2.5 type species of this doubtful genus is A. billion years ago. Archaeozoic asiaticus. means "ancient life."

ARCHAEOTHYRIS

Archaeothyris is the oldest-known ARCHELON pelycosaur. This long-tailed quadruped lived Archelon was huge marine turtle (a in warm, humid forests of the early-mid chelonian) that lived during the late Pennsylvanian period, about 300 million Cretaceous period. It was not a years ago. Archaeothyris looked sperficially dinosaur. Archelon had a wide, like a lizard and was about 20 inches (50 cm) flattened shell, paddle-like legs, a long, long. This carnivore (meat-eater) had strong narrow head, weak jaws, and a pointed jaws and sharp, pointed teeth; it may have tail. It may have eaten jellyfish. eaten small reptiles like Hylonomus. Fossils Archelon's back probably had a have been found in Nova Scotia, North leathery covering or horny plates over America. Clasification: Subclass Synapsida, a bony framework on its back. This Order Pelycosauris, Family Ophicodontia. carnivore was about 10-13 feet (3-4 m) long. Fossils have been found in Kansas and South Dakota, USA.

ARCHIMEDES Archimedes was a corkscrew-shaped colonial genus of bryozoan named for ARCHILLOBATOR the ancient Greek Archimedes, who Achillobator (Achilles was a Greek hero with invented the water screw (the bryozoan a vulnerable heel tendon and bator is looks like the water screw). The marine Mongolian for hero) was an advanced meat- bryozoan Archimedes were tubular- eating dinosaur that was about 16 ft (5 m) shaped zooids with calcified walls. long. This large dromaeosaur They lived in colonies during the (deinonychosaur) has a sickle-shaped claw Carboniferous, roughly 360 to 280 on each foot. This theropod lived during the million years ago. Classification: late Cretaceous periodA. giganticus. Kingdom Animalia, Phylum Bryozoa, Class Stenolaemata, Order Fenestrida, Family Fenestellidae, Genus Archimedes, many species.

ARCHOSAUR ARCHITEUTHIS (pronounced ARK-uh-sawr) (pronounced ark-ee-TOO-this) Architeuthis is the Archosaurs (meaning "ruling giant squid. It is the largest squid and the largest lizard") were reptiles that invertebrate (animal without a backbone), but it dominated the Mesozoic Era. has never been seen since it lives very deep in the They included the crocodilians, oceans. The largest-known Architeuthis was 57 pterosaurs, thecodonts, dinosaurs feet (17.5 m) long. It has eight arms, two longer (and birds). feeding tentacles, a beak, a large head, and two eyes larger than basketballs! These soft-bodied cephalopods are fast-moving carnivores that catch prey with their tentacles, then poison it with a bite from beak-like jaws. They move by squirting water through a siphon, a type of jet propulsion. Only dead examples of Architeuthis have been found. Its only enemy is the sperm whale who hunts it deep in the ocean.

ARCTOSAURUS

(pronounced ARK-toh-SAWR-us) Arctosaurus meaning "arctic lizard" was a meat-eating dinosaur that lived ARGENTINOSAURUS (pronounced ahr-gen-TEEN-oh-SAWR-us) during the late Triassic period. This Argentinosaurus huinculensis was a 130-140 theropod was about 10 feet (3 m) long. feet (40-42 m) long titanosaurid sauropod. It Fossils of Arctosaurus were found in was an enormous, long-necked, long-tailed, Canada . Arctosaurus was described in quadrupedal, plant-eater from Argentina, 1875 by Adams. The type species is A. South America during the Cretaceous period. osborni, but Arctosaurus is nomen Argentinosaurus, meaning "Argentina dubium (only neck vertebrae have been Lizard," was named by paleontologists Coria found and it may or may not even be a & José Bonaparte in 1993. It is known from theropod). fossilized back vertebrae, tibia, ribs and sacrum. It may be the largest dinosaur.

ARGYROSAURUS (pronounced AHR-ji-ro-SAWR-us) Argyrosaurus (meaning "silver lizard") was a large plant-eating dinosaur about 70 ft (21 m) long weighing roughly ARISTOSAURUS 20000 kg. This massive quadruped. Some limbs (pronounced uh-RIST-uh-SAWR- have been found in Argentina and Uruguay. It us) Aristosaurus is an invalid dates from the late Cretaceous period, about 73-65 name for Massospondylus, an million years ago. This sauropod, perhaps an herbivorous Saurischian dinosaur armoured titanosaurid, was named by Lydekker in from the late Triassic period. 1893. The type species of this doubtful genus is A. superbus. ARISTOSUCHUS ARKANSAURUS (pronounced uh-RIST-uh-SUE-kus) (pronounced AHR-kan-SAWR-us) Aristosuchus (meaning "best lizard") is an Arkansaurus (meaning "Arkansas lizard") old (invalid) name for Calamospondylus. was a bird-like, bipedal, meat-eating It was a bipedal, meat-eating theropod dinosaur (a theropod) that lived during the dinosaur with large hand claws. This late Cretaceous period. (It is a coelurosaur coelurosaur dates from the early and perhaps an ornothimimid.) This Cretaceous period, about 125 million dinosaur is known from foot bones found years old. This predator was perhaps 6.5 ft in Arkansas, USA. Fossilized foot bones (2 m) long, weighing about 65 pounds (30 and claws were found in 1972 by J. B. kg). Friday while looking for a lost cow on his farm near Lockesburg, Arkansas, USA. Arkansaurus was informally named and described by the geologist James Harrison Quinn in 1973, but this dinosaur has not been formally described (hence it is a nomen nudum). The type species is A. fridayi (the species name honors J.B. Friday, who found the fossil and donated it to the University of Arkansas).

ARSINOITHERIUM Arsinoitherium was an early, rhinoceros- ARRHINOCERATOPS like mammal that lived during the early (pronounced aye-RYE-no-SER-uh-tops) Oligocene (about 38 to 23 million years Arrhinoceratops (meaning "without nose- ago). Although it looked like a horn face") was a ceratopsian dinosaur rhinoceros, it is more closely related to about 20 feet (6 m) long, weighing roughly elephants. This large quadruped had 5- 3540 kg. It was a frilled, horned, plant-eater toed legs. It had 2 huge, conical, hollow from the late Cretaceous period, about 72 horns made of bone on its snout. It was million-68 million years ago. It is known about 11.5 feet (3.5 m) long and about 6 from a skull found in Alberta, Canada. It ft (1.8 m) tall at the shoulder. This plant was named by paleontologist Wm. A. Parks eater may have lived in forests near in 1925. The type species is A. brachyops. rivers. Fossils of Arsinoitherium have been found in Faiyum, Egypt. Classification: Class Mammalia (mammals), Subclass Theria, Infraclass Eutheria (placental mammals) Order Embrithopoda, Genus Arsinoitherium. ARSTANOSAURUS (pronounced ahr-stahn-oh-SAWR-us) Arstanosaurus (meaning "Arstan ARTHROPLEURA (Kazakhstan) lizard" ) was a lambeosaurine (pronounced AHR-throw-PLOOR-ah) hadrosaur dinosaur (it was originally though Arthropleura was a six-foot long to be a ceratopsian) roughly 50 feet (15 m) myriapod (related to millipedes), an long. It was a beaked plant-eater from the arthropod with spines jutting out all late Cretaceous period, about 87.5 million- along the sides of its exoskeleton. This 73 million years ago. It is known from a jointed animal lived in damp forests very incomplete skeleton found in during the Carboniferous (roughly 300 Kazakhstan. Arstanosaurus was named by million years ago). paleontologists Suslov and Shilin in 1982. The type species is A. akkurganensis. ARTHURDACTYLUS Arthurdactylus conan-doylensis (named for Sir Arthur Conan Doyle, who wrote "The Lost ARTHROPODS World") was a pterosaur (not a dinosaur). This (pronounced AHR-throw-pods) Pterodactyloid had an estimated wingspan 15 feet Arthropods are a group of animals (4.6 m); this pterodactyl has wings that were with exoskeletons made of chitin, proportionately longer than any other pterosaur. segmented bodies, and jointed Fossils of this flying reptile were found in limbs. Insects, arachnids, northeastern Brazil . This carnivore lived during trilobites, crustaceans, and others the early Cretaceous period. Arthurdactylus was are arthropods. described in 1994 by E. Frey and D. Martill.

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ASIACERATOPS (pronounced AY-zha-SER-ah-tops) ASIATOSAURUS Asiaceratops (meaning "Asian horned (pronounced AYE-see-at-tuh-SAWR-us) face") was a primitive ceratopsian, a Asiatosaurus (meaning "Asian lizard") quadrupedal, beaked, horned, frilled, was a large sauropod, a quadrupedal plant-eater from Kazakhstan during the plant-eater from Mongolia during the late Cretaceous period, about 97.5 to 90 early Cretaceous period. Only million years ago. It was about 6-7 ft (2 m) fragmentary fossils of Asiatosaurus have long and weighed about 180 kg. It was been found. It was named by similar to Montanoceratops. Only paleontologist Henry Osborn in 1924. The fragmentary fossils of Asiaceratops have type species is A. mongoliensis. been found. It was named by paleontologists Nessov and Kaznyshkina in 1989. The type species is A. salsopaludalis. ASTRODON (pronounced AS-troh-don) Astrodon (meaning "star-tooth") was a long-necked plant-eating ASTEROID dinosaur, a brachiosaurid sauropod that was about An asteroid is a large rock or 30? feet (9 m) long (which is small for a small planet from the belt that brachiosaurid). It lived during the early Cretaceous orbits the sun between Mars and period, about 130 million-120 million years ago. Jupiter. An asteroid impact with Astrodon is known only from fossilized teeth the Earth may have caused the found in Maryland, USA (Astrodon is the state extinction of the dinosaurs. dinosaur of Maryland). Astrodon was named by Johnston in 1859. The type species is A. johnstoni. Astrodon may be the same as Pleurocoelus. ATLASCOPCOSAURUS (pronounced AT-las-KOP-kuh-SAWR-us) Atlascopcosaurus (named for the company Atlas Copco [Compagnie Pneumatique Commerciale], that donated some of the equipment for the dig) ATLANTOSAURUS was an ornithopod about 6.5 to 10 feet (2 to 3 m) (pronounced at-LAN-tuh-SAWR- long and weighed roughly 125 kg. It was a plant- us) Atlantosaurus ("Atlanta eater that lived during the early Cretaceous period. lizard") is a doubtful genus and is It is known only from fossilized jaws and teeth probably Apatosaurus. It was found in Australia. It was named by T. Rich & P. named by Marsh in 1877. Rich in 1989. The type species is A. loadsi ATREIPUS (pronounced ah-TREE-ih-pus) Atreipus is a poorly-known ornithischian (bird-hipped) dinosaur known only from its fossilized tracks. No fossilized bones have been attributed to this ichnogenus. Two sizes of footprints (4.5 and 1 cm ATOM long) have been found in conjunction, indicating that this Everything is made up of small dinosaur walked on four legs and its rear legs were tiny atoms. An atom is the much larger and longer than the front legs. Atreipus was smallest part of an roughly 6 feet (1.8 m) long. Trackways were found in element that has the Pennsylvania, USA Mike Szajna and Brian Hartline. It properties of that element. lived during the late Triassic period, about 220 million years ago. The type species is Atreipus milfordensis

AUBLYSODON AULAPODUS (pronounced ah-BLEECE-oh-don) Aulapodus icels is an ichnogenus, a Aublysodon (meaning "backwards tooth") dicynodont known from its human-sized is a poorly-known theropod dinosaur footprints, which were made during the (perhaps a tyrannosaurid) about 15 feet (4.5 Permian period, roughly 255 years ago. m) long, weighing about 80 kg. It was a According to paleontologist James meat-eater from the western USA during Kitching, Aulapodus is Aulacephaledon, the late Cretaceous period, about 76 a relatively common dicynodont known million-65 million years ago. Its front teeth from the area. The tracks of this plant- were long and sharp but not serrated. It was eating, tusked therapsid were found in named by paleontologist J. Leidy in 1868. the Karoo near Grahamstown, Eastern It is only known from teeth and partial Cape, South Africam which was a marsh skulls. The type species is A. mirandus during the Permian period. Aulapodus was named by geologist Billy de Klerk in 1998. The tracks were found by IC ''Ice'' Els, a very perceptive road builder.

AUROCHS AUSKTRIBOSPHENOS (pronounced OR-rox) Aurochs Ausktribosphenos nyktos (meaning "Australian was a large, wild ox that lived in Cretaceous tribosphenic mammal that lived during Europe. This hoofed mammal (an the night") was a small mammal that lived during artiodactyl) went extinct in 1627. the Cretaceous period, about 115 million years It was black and had forward- ago. This insect-eater was not a dinosaur, but it curving horns; it stood about 6 feet lived during the time of the dinosaurs. Its (1.8 m) tall at the shoulder. The fossilized jaw was found by Nicola Barton in aurochs was the ancestor of 1997 at Flat Rocks, southeast of Melbourne, domestic cattle. The genus and Australia. Ausktribosphenos may have been species are Bos primigenius. nocturnal. It is the oldest-known mammal from Australia, and was neither a marsupial nor a monotreme (it may have been a placental mammal or a new type of mammal). Ausktribosphenos was named by Tom Rich and Pat Vickers-Rich. AUSTROSAURUS (pronounced AW-stroh-SAWR-us) Austrosaurus (meaning "southern lizard") is a poorly-known sauropod (perhaps a AUTOTROPH cetiosaurid) dinosaur about 50 feet (15 m) (pronounced AW-toh-trofe) An long, weighing roughly 20000 kg. It was a autotroph (or producer) is an organism plant-eater during the early Cretaceous that makes its own food from light period, about 113 million-98 million years energy or chemical energy (inorganic ago. Incomplete fossils were found in matter) without eating. Most green Queensland, Australia. It was named by plants, many protists (one-celled paleontologist J. Longman in 1933. It is only organisms like slime molds) and most known from teeth and partial skulls. The bacteria are autotrophs. Autotrophs are type species is A. mckillopi the base of the food chain.

AVACERATOPS AVIMIMUS (pronounced AY-vuh-SUR-uh-tops) (pronounced AH-vee-MIME-us) Avaceratops was a small, horned, frilled Avimimus (meaning "bird mimic") was ceratopsian dinosaur about 7-14 feet (2-4 m) a very fast moving, long-legged, bird- long, weighing roughly 1200 kg. It was a like theropod dinosaur about 5 feet (1.5 beaked plant-eater from Montana during the m) long, weighing about 14 kg. It was a late Cretaceous period, about 77 million-73 long-beaked carnivore from Mongolia million years ago. It was named by Canadian during the late Cretaceous period, about paleontologist Peter Dodson in 1986. It is 85 million-75 million years ago. It may known from partial skulls. The type species have had feathers. It was named by is A. lammersi Russian paleontologist Sergei Mikhailovich Kurzanov in 1981. The type species is A. portentosus

AZHDARCHO AVIPES (pronounced as-DAR-choh) Azhdarcho (pronounced AH-vee-MIM-us) Avipes (meaning "dragon") was a pterosaur, a (meaning "bird foot") was a small theropod flying reptile, not a dinosaur. It was a dinosaur or lagosuchian (reptiles that led to carnivore that lived during the late the dinosaurs) with bird-like feet (hence its Cretaceous period. It is known from name). It was a long-beaked carnivore from fossils found in Uzbekhistan. It was Germany during the middle Triassic period. named by Nessov in 1984. It was named by paleontologist von Huene in 1932. The type species is A. dillstedtianus

AZENDOHSAURUS (pronounced ah-ZEN-doh-SAWR-us) Azendohsaurus (meaning "Azendoh [Morocco] lizard") was an early plant-eating dinosaur, a prosauropod about 6 ft (1.8 m) long. It is known only from a partial jaw and some teeth found in Morocco. It lived during the late Triassic period, about 228 million years ago. It was named by paleontologist Dutuit in 1972. The type species is A. laaroussii

Ta Ta Te Th Ti To Tr Ts-Tu Ty TANGVAYOSAURUS TALIRURUS Tangvayosaurus (meaning "Tang Vay lizard") (pronounced TAL-a-RU-rus) was a large, long-necked, quadrupedal, plant- Talarurus (meaning "wicker [basket] eating dinosaur (an titanosaurid). This tank-like tail") was a large, armoured, dinosaur was about 6 m long. Talarurus lived quadrupedal, plant-eating dinosaur during the late Cretaceous period, about 120 to (an ankylosaurid). This tank-like 99 million years ago. Fossils have been found dinosaur was about 6 m long. in Laos, Asia. Talarurus was named by Talarurus lived during the middle paleontologists Allian, Taquet, Battail, Dejax, Cretaceous period, about 99 to 90 Richir, Veran, Limon-Duparcmeur, Vacant, million years ago. Fossils have been Mateus, Sayarath, Khenthavong and found in Mongolia, Asia. Talarurus Phouyavong in 1999; the type species is T. was named by Maleev in 1952; the hoffeti. may be the same as Titanosaurus type species is T. plicatospineus. falloti. TANYSTROPHEUS TANIUS (pronounced TAN-ee-STRO-fee-us) (pronounced TAN-ee-us) Tanius Tanystropheus was a long-necked reptile (not a was a large, crestless Hadrosaurid dinosaur) that dates from the middle Triassic from China. These heavily-built period. It looked like a lizard with a plant-eaters were duck-bills that had ridiculously long neck. Its neck was 10 feet (3 a bony protuberance between the m) long, longer than its body and tail put eyes on their flat head. Tanius had a together. Some of the 10 neck vertebrae (neck toothless beak and strong jaws with bones) were over 1 foot (30 cm) wide. It had 4 self-sharpening cheek teeth (for legs, a tail, and was about 20 feet (6 m) long. chewing tough plant material). It had This fish-eater had peg-like teeth. four-fingered hands and could walk Tanystropheus may have spent a lot of time on on 2 or 4 legs. Tanius dates from the the water, but it was neither well adapted for late Cretaceous period, about 88.5 to swimming nor walking. It may have lived on 65 million years ago. Tanius was the shore and fished with its long neck and named by Carl Wiman in 1929, after head! Fossils of Tanystropheus have been found the "Tanka" people of southern in Europe and the Middle East. It may have China. been related to the Nothosaurs. Classification: Order Squamata (lizards and snakes). TAPEJARA (pronounced TAP-ah-JAR-ah) Tapejara (meaning "old being" in Tupi) was a pterosaur that dates from the early Cretaceous period, about 132 to 100 million years ago. TAPHONOMY This flying reptile ate fish and lived near the Taphonomy (which means 'laws of sea. A Pterodactyloid, it had a wingspan of burial') is the science that studies the about 16.5 feet (5 m) and a short tail. It had a process of decay and fossilization. The large head crest formed by skin stretched Russian paleontologist Ivan A. between two bony crests on its head, one Efremov coined the term taphonomy above the nostrils, the other behind and above and founded the study of taphonomy in the eyes. The tip of its lower jaw turned 1940. downward. Fossils have been found in Northeast Brazil. Tapejara was named by Kellner in 1989. The type species is T. wellnhoferi. TARCHIA (pronounced TAHR-key-ah) Tarchia (meaning "brainy one") was an armoured, plant-eating dinosaur that dates from the late Cretaceous period, TARBOSAURUS about 78-69 million years ago. This (pronounced TAR-bow-SAWR-us) ankylosaurid ankylosaur was about 18 Tarbosaurus is an invalid name for feet (5.5 m) long and weighed roughly Tyrannosaurus bataar or T. efremovi, Asian 10,000 pounds (4500 kg). It had theropods smaller than Tyrannosaurus rex. T. spikes running along its sides and at bataar was about 30 to 40 feet (9 to 12 m) the corners of its mouth. This long and weighed 4 to 5 tons. T. efremovi was lumbering quadruped had a large tail about 23 to 26 feet (7 to 8 m) long and club and a large braincase. Seven weighed 2 to 3 tons. Both adult and juvenile fossils have been found in Mongolia. skeletons have been found. It was named by Tarchia was named by Maryanska in Maleev in 1955. 1977. The type species is T. gigantea. TAR PIT A tar pit is a pool of gooey asphalt. It is created when crude oil seeps up from deep inside the Earth through a crack (called a fissure) - millions of years of time and intense pressure convert ancient organisms, like plankton, into oil. The less dense elements of the crude TARSAL oil evaporate, leaving asphalt (a very sticky mess). Water pools on the A tarsal is an tar, attracting thirsty animals. As an animal gets stuck in the tar, it ankle bone. attracts predators, who also get stuck. The animals' bones, teeth, and other hard parts are well-preserved in this environment (but they turn brown from the asphalt). Tar pits are located around the world. A famous tar pit is the Rancho La Brea Tar Pits (in southern California, USA). TAXON A taxon is category in the classification of living organisms. The taxa (the plural of taxon) in the Linnean system are kingdom, phylum, class, TAXONOMY order, family, genus, and species. Taxonomy is the science of classifying organisms into groups by structure, origin, common ancestor, etc.

Tr Ta Te Th Ti To Tr Ts-Tu Ty

TRACE FOSSILS Also known as ichnofossils, these are fossilized footprints, nests, dung, gastroliths, etc., TRACHODON but not actual body parts. (pronounced TRACK-oh-don) Trachodon (meaning They record the movement "rough tooth") is a plant-eating dinosaur that is known and behavior of animals. only from a few teeth and parts of the jaw that were found in Montana, USA. It dates from the late Cretaceous period, about 77-73 million years ago. From the teeth, it has been surmised that it was probably a duck-billed dinosaur (a lambeosaurine hadrosaur). Trachodon was named in 1856 by Joseph Leidy; the typs species is T. mirabilis. This is a dubious genus due to the sparsity of fossils.

TRANSGRESSION Transgression is the flooding of a continent as TRACKWAYS the sea level increases, usually caused by Many animal track fossils (fossilized melting polar ice. Another cause is sea floor footprints) have been found. They spreading and underwater volcanism, in which can indicate the animal's speed, large amounts of underwater lava cause water weight, and herding behavior. to be displaced onto land. Determining which animal made the tracks can be difficult.

TREE FERN Tree ferns are tall vascular plants that live in warm climates. These ferns have a clump of fronds on T. rex top of a fibrous trunk. (pronounced TEE recks) Tyrannosaurus rex (meaning "tyrant lizard king") was a huge, meat- eating theropod dinosaur from the late Cretaceous period.

TRIADOBATRACHUS Triadobatrachus massinoti is the earliest-known salientian, a proto-frog. Morphologically, it is between a salamander and a frog. This 4 inch (10 TRIASSIC PERIOD cm) long amphibian lived during the early Triassic (pronounced tri-ASS-ik PEER- period, about 250 million years ago. A single fossils ee-ud) Dinosaurs and mammals was found in Madagascar. Triadobatrachus had long evolved during the Triassic jumping hind legs and a well-developed eardrum. It period, 248 - 208 million years had a short body, a short tail, and 14 back vertebrae ago. (compared to 5 to 9 vertebrae in modern frogs). Classification: Order Proanura.

TRICONODONT Triconodonts (meaning "three-coned teeth") were small, early mammals that lived from the Triassic period until the Cretaceous period (from about 200-100 million years ago). These long- tailed, quadrupedal mammals had three-cusped TRICERATOPS teeth (hence their name) and ranged from a just a (pronounced tri-SER-uh-tops) few inches long to the size of a cat. They had Triceratops was a frilled dinosaur, a relatively advanced, grasping hands, but a ceratopsian, from the late primitive pelvis and hind limbs. These Cretaceous period that had three insectivores may have had large eyes, and may horns on its head. This plant-eater have been nocturnal (most active at night). The was about 25 feet (8 m) long. most complete triconodont, the 5 inch long, 125 million-year-old Jeholodens jenkinsi, was recently found in Lianong, China.

TRIGONIAS TRILOBITE (pronounced tri-GO-nee-us) Trigonias was one of (pronounced TRI-low-bite) the earliest rhinoceroses. It lived during the early Trilobites were early Oligocene Epoch, about 35 million years ago. This invertebrates with a segmented large, plant-eating mammal was about 8 ft (2.5 m) body and an exoskeleton. long, had five-toed front feet, and had more teeth Trilobites dominated the than modern-day rhinos. It did not have a snout environment during the "horn," as modern-day rhinos do. Fossils have been Cambrian Period (540 to 500 found in Europe (France) and western North mya). America (Montana). The type species is Trigonias osborni. Classification: Order Perissodactyla (odd- toed ungulates), Suborder Ceratomorpha (tapirs, rhinos), Family Rhinocerotidae, Genus Trigonas. Photo courtesy of Jim Puckett.

TRIOLOPHODON Trilophodon (meaning "three crested tooth") was an ancient mammal that lived during the Miocene - it is sometimes called Tetrabelodon. This large Gomphothere was an ancestor of mastodons.

TRIMUCRODON Trilophodon was about 5 m long and 2.5 m Trimucrodon (meaning "triply-pointed high. It was a heavy, plant-eating animal tooth"), Trimucrodon was a small plant- that walked on four column-like legs. It eating dinosaur that lived during the late had a large skull, and elephant-like Jurassic period, roughly 150 million years proboscis, four parallel tusks (two on the ago. A fossilized tooth of this top jaw, two smaller ones on the bottom ornithischian dinosaur have been found in jaw), high-ridged grinding teeth, and a Provincia do Estremadura, Portugal. The short tail. Fossils have been found in type species of this genus is T. cuneatus, Europe (France), Africa (Kenya), Asia named by Thulborn in 1973. Due to the (Pakistan), and North America (Nebraska, lack of fossil information, this genus is a South Dakota). Classification: Kingdom nomen dubium. Animalia, Phylum Chordata, Class Mammalia (mammals), Order Proboscidea, Suborder Elephantiodea (elephants, mastodonts, mammoths), Family Gomphotheriidae, Genus Gomphothere.

TRIOPS (pronounced TRI-ops) Triops (Triops longicaudatus) are TRIONYX small, freshwater crustaceans (often found in rice fields) (pronounced triI-ON-iks) that look a little like trilobites. Also called tadpole shrimp, Trionyx is a genus of soft- they are branchiopods with a hard exoskeleton, and sturdy shelled turtles that first mandibles (jaws). They eat animals and plants, and are appeared during the sometimes cannibalistic. Their life span is about 20 to 40 Jurassic period. days. Triops evolved during the Devonian period, about 350 million years ago (long before the dinosaurs appeared).

TROCHANTER TROÖDON The trochanter is a bony (pronounced TROH-oh-don) Troodon was a very bump on the femur (the thigh smart, human-sized, meat-eating theropod dinosaur bone) to which large muscles from the late Cretaceous period, about 76 to 70 million are attached. years ago. Fossils of Troodon have been found in Montana, Wyoming (USA) and Alberta (Canada). The type species is T. formosus. TROPEOGNATHUS Tropeognathus (meaning "keel jaw") was a pterosaur that lived during the middle Cretaceous period, about 122 to 112 million years ago. This flying reptile ate fish and lived near the sea. A Pterodactyloid, it had a TROPHIC LEVEL wingspan of about 20 feet (6.2 m) and a short tail. The A trophic level is a level of skull was 2.2 feet (67 cm) long. Tropeognathus had a the grazing food chain. For large beak that was enlarged at the tip; it had many example, plant-eaters are sharp teeth. Fossils have been found in the Santana primary consumers; they Formation in norteastern Brazil. Tropeognathus was occupy the second trophic named by Wellnhofer in 1987. The type species is T. level in the grazing food mesembrinus. chain.

TSINTAOSAURUS (pronounced sin-tau-SAWR-us) Tsintaosaurus is a genus of plant-eating, duck-billed dinosaurs (hadrosaurs) of which little is known. Tsintaosaurus TSUNAMI was roughly 33 ft (10 m) long. It may have had a thin, (pronounced sue-NAHM-ee) A hollow bony crest on its head (jutting forwards, or tsunami is a huge wave, caused maybe backwards) but some paleontologists think by undersea earthquakes, that this crest may in fact be an artifact of the volcanic eruptions, or, more fossilization process (Tsintaosaurus may be a rarely, by asteroid or lambeosaurine, a crested hadrodaur). Tsintaosaurus meteoroid impact (as in the lived during the late Cretaceous period. Tsintaosaurus case of the K-T extinction). was named by Young Chung Chien in 1958. Tsintaosaurus means "Tsintao lizard", named for the city of Tsingtao (Ch'ing-tao or Qingdao, which means "green island") near where the fossil was found in the Wangshi Formation, Shandong Province, China. Tsintaosaurus may be the same as Tanius (which was named earlier and therefore retains its name), which was a crestless Hadrosaurid from China. Tanius was named by Carl Wiman in 1929. TULLY MONSTER The Tully monster (Tullimonstrum TUOJIANGOSAURUS gregarium) was a soft-bodied sea (pronounced Too-oh-gee-ANG-oh-SAWR-us) animal with a long proboscis that A stegosaurid, a quadrupedal, plant-eating ended in a "jaw" with eight small, dinosaur about 23 feet (7 m) long with double sharp teeth. Tullimonstrum was an rows of plates along its back, a toothless beak, a active swimmer that was a carnivore long, low-hanging head, spoon-shaped teeth, 2 (meat-eater). It lived roughly 280 to shoulder spikes, and a 4-spiked tail. It was from 340 million years ago, during the the late Jurassic period, about 163-150 million Carboniferous period. Fossils of this years ago in China. It was named in 1977 by unusual organism were first found Shiwu Zhou, Dong, Zhang, and Li. by Francis Tully in Illinois, USA, in 1958. It was named and described scientifically by Dr. Eugene Richardson.

TURTLE Turtles are anapsids, having no extra holes in the sides of their heads. Turtles evolved during the late Triassic period, roughly 220 million years ago, about the same time the dinosaurs and mammals evolved. Proganochelys is the oldest known turtle. Other early turtles include Proterocheris, Saurischiocomes, Chelytherium, Dermoschelys, Notoemys, Platychelys, Trionyx, Baena, Chisternon, and Meiolania

DINOSAUR INFORMATION PAGES: A A B-C D-G H-L M N-O P-R S T U-Z Non-Dinos

There are about 1,000 described dinosaur genera. Below is a sampling of dinosaurs. Just click on a dinosaur to go to an information sheet. The drawings are not to scale. For a page on how to write a great dinosaur report, click here. If the dinosaur (or other prehistoric animal) you're interested in isn't here, check the Dinosaur Dictionary for information.

ACANTHOPHOLIS ALBERTOSAURUS

ACROCANTHOSAURUS

ALLOSAURUS ANATOTITAN AMARGASAURUS

ANKYLOSAURUS APATOSAURUS AVIMIMUS

Dinosaur Coloring/Information Printouts: A

A B C D E-H I-K L-M N-O P-R S T U-Z Non-Dinos Also see our detailed dinosaur information pages and our brief dinosaur fact sheets (with printable versions).

Click on a dinosaur's name to go to a black-and-white print-out. These activities are designed as academic print-outs, for making a dinosaur book, for cut-outs used in dinosaur crafts, for coloring, for stencils, and other uses. For a long version with all the dinosaurs on one page, click here.

Alamosaurus Alamosaurus A huge, long-tailed, long- (Simple Version) Acrocanthosaurus necked, armoured, plant- A long-tailed, long- A huge, spine-backed eating dinosaur. necked, armoured plant- meat-eater. eater.

Allosaurus Albertosaurus The biggest meat- eating dinosaur from Alxasaurus A meat-eating dinosaur, a the late Jurassic A meat-eating tyrannosaurid from the late period. dinosaur found in Cretaceous period. Mongolia.

Ankylosaurus Anchisaurus Ankylosaurus A plant-eating dinosaur, A heavily armoured (Simple Version) a late prosauropod, from plant-eater with a club- A heavily armoured plant-eater with a club- the early Jurassic period. like tail and spikes. like tail and spikes.

Apatosaurus Apatosaurus A huge, long-necked, whip-tailed plant- (Simple version) eating dinosaur; it used to be known as A long-necked plant-eater; it Brontosaurus. used to be known as Brontosaurus

Dinosaur Coloring/Information Print-outs: B

A B C D E-H I-K L-M N-O P-R S T U-Z Non-Dinos Also see our detailed dinosaur information pages and our brief dinosaur fact sheets (with printable versions).

Click on a dinosaur's name to go to a black-and-white print-out. These activities are designed as academic print-outs, for making a dinosaur book, for cut-outs used in dinosaur crafts, for coloring, for stencils, and other uses.

Bagaceratops Barosaurus Printout A huge, long-necked, Baryonyx A plant-eating whip-tailed plant-eater A large meat-eater from the early Cretaceous dinosaur with an from the Jurassic period. armoured head. period.

Brachiosaurus Brachiosaurus A huge, long-necked, plant- (Simple Brachiosaurus eating dinosaur with a giraffe-like stance. version) Skeleton A tall, long-necked Brachiosaurus was a tall, plant-eater. long-necked plant-eater.

SHARKS

SHARK AND RAY INFORMATION SHEETS

There are about 350 different species of sharks, which are divided into 8 orders and 30 families. Below is a sampling of shark species.

Just click on a shark to go to that information sheet. The drawings are not to scale.

BASKING SHARK ANGELSHARK BLACKTIP REEF SHARK

BLUNTNOSE SIXGILL BLUE SHARK SHARK BONNETHEAD SHARK

DOGFISH SHARK BROADNOSE SEVENGILL SHARK BULL SHARK

GALAPAGOS SHARK GOBLIN SHARK GREAT WHITE SHARK

HAMMERHEAD SHARK LEMON SHARK MANTA RAY

MAKO SHARK NURSE SHARK PORBEAGLE SHARK

SPINED PYGMY SHARK

THRESHER SHARK

TIGER SHARK WHALE SHARK

Shark and Ray Print-outs

Click on a shark's name to go to a simple black-and-white print-out. These activities are designed as simple academic print-outs, for making a shark book, for cut-outs used in shark crafts, for coloring, for stencils, etc.

Atlantic Angelsharks Sharpnose Shark Basking Shark A huge filter feeder Bottom-dwelling, relatively A harmless requiem and the second harmless sharks with shark with a sharp flattened bodies and a blunt largest fish. snout. snout.

Basking Shark (Simple Bull Shark Blue Shark A blunt-nosed, dangerous, version) A sleek, fast-swimming gray shark that can also live A huge filter feeder shark with blue skin. in fresh water rivers and and the second lakes. largest fish.

Bull Shark Cookiecutter Shark Dogfish Shark (Simple version) A small shark that takes Small, very common, A blunt-nosed, circular bites out of its prey. relatively harmless dangerous, gray shark Also known as the sharks found can live in fresh water luminous or cigar shark. worldwide. rivers and lakes.

Galapagos Shark Great A large predator found Goblin Shark Hammerhead near islands in warm A bottom-dweller with a Shark water. long, flattened snout. Large predators with a hammer-shaped head.

Great White Great White Shark Greenland Shark Shark A large, slow-swimming An enormous, Simple Version shark with glow-in-the-dark Enormous, ferocious ferocious predator eyes. found worldwide. predators found worldwide.

Lemon Shark Luminous Shark Large, yellowish A small shark that takes Mako Shark circular bites out of its predators found near the Large predators that prey. Also known as the surface and at are the fastest fish!. intermediate depths. cookiecutter or cigar shark.

Megalodon Megamouth Nurse Shark A huge, extinct A large, filter-feeding shark that Large bottom-dwellers shark. was only discovered in 1976. with rounded fins.

Sandtiger Shark Orthacanthus Port Jackson Shark A spined, extinct A shark from waters off (Sand Shark) shark. southern Australia. A shark that is cannibalistic before birth.

Shark Tiger Shark Anatomy Thresher Shark Large predators Label the shark The Thresher Shark is a shark found worldwide in external anatomy whose tail fin has a greatly warm seas. diagram. elongated upper lobe. Answers

Whale Shark Zebra Bullhead Shark The largest fish and a filter feeder that eats A bottom-dwelling shark with tiny marine organisms and small fish. zebra-like stripes.

Rays:

Ray Manta Ray Flattened fish that evolv ed from sharks. The largest ray.

MEGALODON (meaning "Giant Tooth") Go to a Megalodon Printout

Megalodon was an ancient shark that may have been 40 feet (12 m) long or even more. (There are a few scientists who estimate that it could have been up to 50 or 100 feet (15.5 or 31 m) long!) This is at least two or three times as long as the Great White Shark, but this is only an estimate made from many fossilized teeth and a few fossilized vertebrae that have been found. These giant teeth are the size of a person's hand! No other parts of this ancient shark have been found, so we can only guess what it looked like. Since Megalodon's teeth are very similar to the teeth of the Great White Shark (but bigger and thicker), it is thought that Megalodon may have looked like a huge, streamlined version of the Great White Shark.

MEGALODON'S DIET Megalodon's diet probably consisted mostly of whales. Sharks eat about 2 percent of their body weight each day; this a bit less than a human being eats. Since most sharks are cold-blooded, they don't have to eat as much as we eat (a lot of our food intake is used to keep our bodies warm).

TEETH AND JAWS Shark fossils are extremely rare because sharks have no bones, only cartilage, which does not fossilize well. Their teeth, however, are very hard. Their teeth are made of a bone-like material coated with hard enamel and they fossilize very well. Megalodon teeth are similar to those of the Great White Shark, but are much bigger, thicker, and with finer serrrations. Megalodon's jaws could open 6 feet (1.8 m) wide and 7 feet (2.1 m) high. The jaws were loosely attached by ligaments and muscles to the skull, opening extremely wide in order to swallow enormous objects. It could easily swallow a large Great White Shark whole!

Like most sharks, Megalodon's teeth were probably located in rows which rotated into use as they were needed. Most sharks have about 3-5 rows of teeth at any time. The front set does most of the work. The first two rows are used for obtaining prey, the other rows rotate into place as they are needed. As teeth are lost, broken, or worn down, they are replaced by new teeth. Megalodon may have had hundreds of teeth at one time. It did not chew their food like we do, but gulped it down whole in very large chunks.

WHEN MEGALODON LIVED Megalodon lived from roughly 25 to 1.6 million years ago, during the Miocene and Pliocene epochs. It is now extinct, but the exact time of its extinction is hotly debated.

MEGALODON ANATOMY

MEGALODON FOSSILS Fossilized Megalodon teeth up to 6.5 inches (17 cm) long have been found in Europe, India, Oceania (the general area around Australia including New Zealand, New Caledonia, etc.), North America, and South America.

MEGALODON CLASSIFICATION Carcharodon megalodon was named by Agassiz in 1843. There is some debate as to whether megalodon was an ancestor of the Great White Shark or was an evolutionary dead end.

Kingdom Animalia (animals) Phylum Chordata Subphylum Vertebrata (vertebrates) Class Chondrichthyes (cartilaginous fish) Subclass Elasmobranchii (sharks and rays) Order Lamniformes Family Lamnidae (genus Carcharodon) or Otodontidae (genus Carcharocles) Genus Carcharodon (meaning "rough tooth") or Carcharocles (There is currently some debate as to whether the megalodon's genus should be Carcharocles or Carcharodon. Megalodon was once thought to be a direct ancestor of the white shark, Carcharodon carcharias, and so was put in the same genus; new evidence indicates that it not ancestral to the great white shark, so Megalodon was assigned to a new genus, Carcharocles) Species megalodon

PACIFIC ANGELSHARK Squatina californica

GENERAL DESCRIPTION The Angelsharks are flat-bodied sharks, very ray-like. They bury themselves in the sand or mud with only the eyes and part of the top of the body exposed. They have a blunt snout and are camouflaged to blend into the sand and rocks of the ocean bed. They have long, wide fins that look like wings, giving it its name. It is also known as the monk shark, sand devil, and monkfish. Angelsharks are frequently caught for food.

TEETH Angelsharks have small, sharp teeth in trap-like jaws.

SIZE The various species of Angelsharks range in size up to 6.5 feet (2 m) long. The Pacific Angelshark is up to 5 feet (1.5 m) long.

DIET AND FEEDING HABITS Angelsharks eat fish, crustaceans, and mollusks. They spend the day hidden in the sand and rocks of the ocean bed. As fish swim by, the angelshark bursts up and surprises the prey, catching it in its trap-like jaws.

HABITAT Angelsharks are bottom dwellers that live on ocean floors of depths from 10 to 4,300 feet (3 to 1300 m). They live in warm temperate oceans in the southern hemisphere.

DISTRIBUTION Pacific angelsharks are found in the eastern Pacific Ocean , from southern Alaska, USA to Baja, CA, USA and from Ecuador to southern Chile.

REPRODUCTION Angelsharks reproduce via aplacental viviparity with litters of 8-13 live- born pups. In aplacental viviparity, the eggs hatch and the babies develop inside the female's body but there is no placenta to nourish the pups.

SPEED Angelsharks are not extremely fast swimmers. Their prey is even slower.

ANGELSHARK CLASSIFICATION Kingdom Animalia (animals) Phylum Chordata Subphylum Vertebrata (vertebrates) Class Chondrichthyes (cartilaginous fish) Subclass Elasmobranchii (sharks and rays) Family Squatinidae Order Squatiniformes Genus Squatina Species

aculeata africana argentina australis californica dimeril formosa japonica nebulosa oculata squatina tergocellata tergocellatiodes

GREAT WHITE SHARK Carcharodon carcharias

GENERAL DESCRIPTION The great white shark is a streamlined swimmer and a ferocious predator with 3,000 teeth at any one time. This much-feared fish has a torpedo- shaped body, a pointed snout, a crescent-shaped tail, 5 gill slits, no fin spines, an anal fin, and 3 main fins: the dorsal fin (on its back) and 2 pectoral fins (on its sides). When the shark is near the surface, the dorsal fin and part of the tail are visible above the water.

COLORATION Only the underbelly of the great white shark is actually white; its top surface is gray to blue gray. This is useful in hunting its prey. The great white usually strikes from below and its grayish top coloration blends in with the dark water, enabling it to approach the prey unobserved. SIZE Great whites average 12-16 feet long (3.7-4.9 m) long. The biggest great white shark on record was 23 feet (7 m) long, weighing about 7,000 pounds (3200 kg). Females are larger than males, as with most sharks. Shark pups can be over 5 feet (1.5 m) long at birth.

DIET AND FEEDING HABITS Young great white sharks eat fish, rays, and other sharks. Adults eat larger prey, including pinnipeds (sea lions and seals), small toothed whales (like belugas), otters, and sea turtles. They also eat carrion (dead animals that they have found floating dead in the water).

Great whites do not chew their food. Their teeth rip prey into mouth-sized pieces which are swallowed whole.

A big meal can satisfy a great white for up to 2 months.

TEETH The great white shark has 3,000 teeth at any one time. They are triangular, serrated (saw-edged), razor-sharp, and up to 3 inches (7.5 cm) long.

The teeth are located in rows which rotate into use as needed. The first two rows are used in obtaining prey, the other rows rotate into place as they are needed. As teeth are lost, broken, or worn down, they are replaced by new teeth that rotate into place.

SENSES Shark's primarily use their sense of smell followed by their sensing of electric charges. The shark's other senses, like sensing changes in water pressure, eyesight, and hearing, are less important.

The great white's nostrils can smell one drop of blood in 25 gallons (100 liters) of water. (Shark nostrils are only used for smell and not for breathing, like our nostrils. They breathe using gills, not nostrils.)

The sensing of minute electrical discharges in the water is accomplished by a series of jelly-filled canals in the head called the ampullae of Lorenzini. This allows the shark to sense the tiny electrical fields generated by all animals, for example, from muscle contractions. It may also serve to detect magnetic fields which some sharks may use in navigation.

The great white is the only type of shark that will go to the surface and poke its head up out of the water. No one knows exactly why it does this; perhaps it is to see potential prey such as surface-dwelling sea lions.

GREAT WHITE SHARK ATTACKS Most great white attacks are not fatal. Great whites account for about 1/2 to 1/3 of all 100 annual reported shark attacks. Of these 30-50 great white attacks, only 10-15 people die.

SOCIAL GROUPS Great whites are usually solitary animals but are occasionally spotted travelling in pairs.

HABITAT Great white sharks are found near shore along most of the temperate (not very hot and not very cold) coastlines around the world.

DISTRIBUTION Great white sharks have been observed along the coastlines of California to Alaska, the east coast of the USA and most of the Gulf coast, Hawaii, most of South America, South Africa, Australia (except the north coast), New Zealand, the Mediterranean Sea, West Africa to Scandinavia, Japan, and the eastern coastline of China and southern Russia.

MIGRATION In the fall, some females migrate to warmer waters (for example, southern California) to give birth.

SWIMMING Great whites are propelled through the water by their powerful tails. The fins are only used for balance. Their movement is more like an aircraft's flight than other fishes swimming. They average about 2 mph (3.2 kph) but can swim 15 miles per hour (24 kph) in short bursts.

They swim constantly or they will sink since, like other sharks, they have no gas filled swim bladder to keep them afloat like bony fish do. Like other sharks, their large, oily liver provides some buoyancy (floating ability). but they are still heavier than water and will sink unless they are propelling themselves through the water. Also like other sharks, they cannot swim backwards or even come to an abrupt stop, because their fins are not flexible like other fish. In order to go backwards, they must stop swimming and fall backwards, using gravity to propel themselves backwards.

It has been recently discovered that great white sharks can jump out of the water. They jump into the air from deep water in order to catch fast- swimming seals

REPRODUCTION Great white sharks reproduce via aplacental viviparity; they give birth to 2- 14 fully-formed pups that are up to 5 feet (1.5 m) long. Like all sharks, fertilization of the eggs occurs within the female. The eggs hatch within the female and are nourished by eating unfertilized eggs and smaller siblings in the womb. There is no placenta to nourish the babies - they must fend for themselves, even before birth. They swim away from the mother immediately after birth, there is no maternal care-giving.

LIFE SPAN No one knows the life span of the great white shark. Some people estimate it to be about 100 years, but this has not been proven.

POPULATION COUNT Great whites are decreasing in numbers and are rare due to years of being hunted by man. They are a protected species along the coasts of California, USA, Australia, and South Africa.

GREAT WHITE SHARK CLASSIFICATION

Kingdom Animalia (animals) Phylum Chordata SubPhylum Vertebrata (vertebrates) Class Chondrichthyes (cartilaginous fish) Subclass Elasmobranchii (sharks and rays) Order Lamniformes Family Lamnidae Genus Carcharodon Species C. carcharias

GREAT WHITE SHARK ACTIVITIES A coloring/information print-out about the great white shark.

A simple coloring print-out about the great white shark.

A first grade shark addition activity. Solve the 1-digit addition problems, then do letter substitutions to answer a shark question.

GREAT WHITE SHARK LINKS A page about the great white shark at UCMP Berkeley.

GREAT WHITE SHARK BOOKS The Great White Shark by Richard Ellis & John McCosker, 1991, Harper Collins, New York. Cousteau's Great White Shark by Jean-Michel Cousteau, 1992, H. N. Abrams, New York

GREAT HAMMERHEAD SHARK Sphyrna mokarran

GENERAL DESCRIPTION The great hammerhead shark has a wide, thick head with the eyes at the margins. The head is indented at the center of the "hammer," which is almost rectangular in shape. This shark is gray-brown above with an off- white belly. The first dorsal fin (the large fin on the top of the shark that most people associate with sharks) is very large and pointed.

TEETH Teeth are triangular with extremely serrated edges.

SIZE The average great hammerhead shark is up to 11.5 feet (3.5 m) long. The largest reported was 20 feet (6 m) long. These large sharks average about over 500 pounds (230 kg) but can weigh as much as 1,000 pounds (450 kg).

There are 9 species of hammerhead sharks, ranging in size from about 3 feet (0.9 m) long to over 20 feet (6 m).

DIET AND FEEDING HABITS The great hammerhead is a fierce predator with a good sense of smell that helps it find its prey. The great hammerhead eats fish, including rays, and other sharks, squid, octopuses, and crustaceans. The great hammerhead has been known to be cannibalistic.

Stingrays seem to be a particular favorite of the great hammerhead. It kills the ray by using its "hammer" to pin the stingray down while it takes bites from the ray's wings.

HAMMERHEAD SHARK ATTACKS Many of the hammerheads are harmless to people, but a few species, like the great hammerhead, can be very dangerous.

HABITAT The great hammerhead swims in warm and relatively warm water along the coastlines. They live over the continental shelves and the adjacent drop-off (the upper part of the mesopelagic zone) to depths of about 260 feet (80 m). DISTRIBUTION The great hammerhead is found in tropical and sub-tropical waters worldwide.

MIGRATION The great hammerhead migrates seasonally to cooler waters during the summer.

REPRODUCTION The great hammerheads are viviparous, giving birth to live young. The 20- 40 pups are about 27 inches (70 cm) long at birth.

HAMMERHEAD SHARK CLASSIFICATION

Kingdom Animalia (animals) Phylum Chordata SubPhylum Vertebrata (vertebrates) Class Chondrichthyes (cartilaginous fish) Subclass Elasmobranchii (sharks and rays) Order Carcharhiniformes Family Sphyrnidae

Genus Eusphyra o Species blochii: the winghead shark Genus Sphyrna o Species corona: Scalloped bonnethead o Species couardi: Whitefin hammerhead o Species lewini: Scalloped hammerhead, bronze hammerhead, kidney- headed shark o Species media: Scoophead o Species mokarran: Great hammerhead o Species tiburo: Bonnethead, shovelhead, bonnet shark o Species tudes: Smalleye hammerhead o Species zygaena: Smooth hammerhead, balance fish, black hammerhead