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Dinosaur and Paleontology Dictionary

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The Earth is the third planet from the Sun.


Echinoderms (meaning "spiny skin") are a phylum of salt-water animals whose living members have five arms or rays (or multiples of five). They are mostly bottom-dwellers. These invertebrates include: starfish (sea stars), sea urchins, sand dollars, crinoids, sea squirts, sea cucumbers, etc.


(pronounced ee-KINE-oh-don) Echinodon (meaning "spiny tooth") was a small, early, bipedal, plant-eating dinosaur from the late Jurassic period, about 145 million years ago. This poorly-known ornithischian was about 2 ft (60 cm) long. It is known from a very incomplete fossil found in Dorset, England. Echinodon was named by Owen in 1861. The type species is E. becklessi. Its classification is uncertain.


Ectotherms are animals whose internal temperature changes with the environment (they are cold-blooded). They rely upon the external temperature and their behavior (like sunning themselves) to regulate their body temperature. Amphibians, most fish, and most reptiles are ectothermic.


(pronounced ah-DAFF-oh-SAWR-us) Edaphosaurus (meaning "pavement lizard" - Cope's term for its tooth plates) was an herbivorous early synapsid that lived during the late Carboniferous and early Permian period, about 320 to 258 million years ago, long before the dinosaurs existed. This pelycosaur (early synapsids) was related to Dimetrodon and had long spines growing out of its backbone. These spines had distinctive crossbars on them and may have been covered by skin, forming a thermoregulatory sail. This quadruped was about 11 feet (3.2 m) long and weighed about 660 pounds (300 kg), had a small head, large eyes, a barrel-shaped body, and a long tail. It lived in wet areas (in swamps and near lakes) and ate rough plant material that it could crush with its flat teeth. Its fossils have been found in Europe and North America.


Edentulous means toothless.


Ediacaran fauna is the animal life that lived during the Vendian or Ediacaran period (roughly 650 to 544 million years ago). The Ediacaran period was named for the Ediacara Hills in South Australia (the word Ediacaran is of Australian Aboriginal origin and means a place where there is water). The Vendian is when the earliest-known animals evolved. Vendian biota (Ediacaran fauna), included soft-bodied multi-cellular animals, like sponges, cnidarians, worms, and soft-bodied relatives of the arthropods. The Ediacara was named for the Ediacara Hills in Australia, north of Adelaide, where these early animal fossils were first found (in 1946, by the Australian mining geologist Reginald C. Sprigg). Other Vendian Period fossils have been found in Mistaken Point, Newfoundland, and the White Sea off the northern coast of Russia.


(pronounced ed-MARK-ah) Edmarka (named to honor Wm. Edmark) was a large meat-eating dinosaur that lived during the late Jurassic period. This theropod was about 36 ft (11 m) long and lived in what is now Wyoming, USA; only a few bones have been found. It was named by paleontologists Bakker, Kralis, Siegwarth, and Filla in 1992. The type species is E. rex. Edmarka may be the same as Torvosaurus.


(pronounced ed-mon-TONE-ee-ah) Edmontonia (meaning "from Edmonton") was an Ankylosaur, a heavily armored herbivore (plant-eater) that was 20 - 23 ft (6 - 7 m) long. It was covered with bony plates and spikes, and had a wide, flat skull. The teeth were small and the jaws were weak. The legs were thick and the feet were very wide. It was a late Cretaceous (76-68 million years ago) ornithischian dinosaur whose fossils were originally found in 1924 in Alberta, Canada (the fossils were unearthed in the Red Deer River valley about 11 kilometers (7 miles) west of the town of Morrin, near the Edmonton rock formation, hence its name) by George Paterson. Edmontonia fossils have been found in Canada (Alberta) and the USA (Montana, S. Dakota, and Texas). Edmontonia was named by the fossil hunter C. M. Sternberg in 1928. The type species is E. longiceps.


(pronounced ed-MON-toh-SAWR-us) Edmontosaurus was a large, Cretaceous, plant-eating, duck-billed dinosaur.


(pronounced ee-FRAYS-ee-ah) Efraasia (named after its discover, Eberhard Fraas) was a sauropodomorph (a primitive plant-eating dinosaur from the late Triassic period in what is now Germany. It was 8 ft = 2.5 m long). Efraasia is actually a juvenile specimen of the genus Sellosaurus.


Some animals hatch from eggs. Fossilized eggs from some prehistoric animals have been found.


(pronounced eye-nee-oh-SAWR-us) Einiosaurus (meaning "bison lizard") was a quadrupedal (walked on four legs), plant-eating dinosaur that lived during the late Cretaceous period, about 71 million years ago. This ceratopsian was roughly 20 feet (6 m) long. It had a large nose horn and a frill. Three skulls and a few bones were found in 1970 in Montana, USA. Einiosaurus was named by paleontologist Sampson in 1995. The type species is E. procurvicornis.


(pronounced EL-ah-fro-SAWR-us) Elaphrosaurus (meaning "light lizard") was a fast, bipedal (walked on two legs), meat-eating dinosaur that lived during the late Jurassic period, about 155 million years ago. It was about 17 feet (5 m) long and had short, thin arms with 3-fingered hands, strong, long-shinned legs, 3-toed feet, a long thin neck and a stiff tail. It may have been an ornithomimid ("bird-mimic") dinosaur, the family of fast-moving theropods. Its fossils have been found in Tanzania, East Africa.


(pronounced eh-LAZZ-mo-SAWR-us) Elasmosaurus (meaning "plate lizard") was a huge, long-necked, Cretaceous marine reptile - a plesiosaur, not a dinosaur.


(pronounced ee-LAS-mo-THEER-ee-um) Elasmotherium (meaning "plate monster") was an ancient plant-eating mammal that lived during the Pleistocene. This heavily-built quadruped walked on four short, stocky hoofed legs. It had a huge horn on its forehead; the horn may have been up to 6.5 ft (2 m) long (fossils of the horn have not been found). Elasmotherium was bigger than an elephant; it was 16-26 ft (5-8 m) long and it weighed roughly 3.5 to 4.5 tons (3-4 tonnes). The teeth were tall-crowned and were covered with cement and wrinkled enamel. Fossils have been found in Europe and Asia; this giant lived and grazed on the Eurasian steppes. Elasmotherium sibricus was named by Johannes Fridericus Brandt in 1878. Classification: Class Mammalia (mammal), Order Perissodactyla (odd-toed ungulates), Suborder Ceratomorpha (tapirs, rhinos), Family Rhinocerotidae (Elasmotherium, Teleoceras, Trigonias, Coelodonta), Genus Elasmotherium.


(pronounced ELM-ee-SAWR-us)Elmisaurus (meaning "foot lizard") was a bipedal (walked on two legs), meat-eating dinosaur that lived during the late Cretaceous period, about 80-70 million years ago. This theropod is only known from fossilized hands and feet; the bird-like feet had 3 long toes (with some fused metatarsals) and a dewclaw. Elmisaurus may have been roughly 6.5 feet (2 m) long. It was found in 1970 in the Gobi Desert, Mongolia. It was named by paleontologist Osmólska in 1981. The type species is E. rarus.


(pronounced ee-LOP-ter-iks) Elopteryx ("marsh wing") was a theropod dinosaur (a bipedal meat-eater) from the late Cretaceous period, about 73-65 million years ago. It may be a Troodontid. A femur (thigh bone) and few fossil fragments were found in Romania. It was named by paleontolgist Andrews in 1913. The type species is E. nopscai, but this is a dubious genus and species (and may be the same as Bradycneme).
(pronounced el-vuh-SAWR-us) Elvisaurus (meaning "Elvis [Presley] lizard") is a an informal name for Cryolophosaurus. It was called Elvisaurus due to its crest's likeness to Elvis Presley's hairdo. It was a bipedal meat-eating dinosaur about 20 feet (6 m) long. It had a horn-like, upward pointing, Elvis-style crest above its eyes. Elvisaurus lived in what is now Antarctica during the early Jurassic period, roughly 190 million years ago. It is the only theropod known from the Antarctic, and the first Antarctic dinosaur ever described. It is known from a partial skull, jaws, femur (thigh bone), pelvis (hip), vertebrae, fibula (calf bone), tibiotarsus (ankle bone), and metatarsals (foot bones).


(pronounced EE-mau-SAWR-us) Emausaurus (meaning "Ernst-Moritz-Arndt Universität (University) lizard") was a plant-eating dinosaur from the early Jurassic period, about 194-188 million years ago. This 6.5 ft (2 m) long ornithischian was a primitive quadruped with cone-shaped and flat armor. It had a wide, flat head with a long snout; it had five teeth on each side of the jaw's front. A skull and some other fossilized bones were found in northern Germany. It may be a thyreophoran or a primitive stegosaur. Echinodon was named by paleontologist Haubold in 1990. The type species is E. rnsti.


(pronounced EM-bah-SAWR-us) Embasaurus (meaning "Emba lizard," named for the Emba River in Kazakhstan) was a meat-eating dinosaur from the late Cretaceous period. It is known from 2 partial vertebrae found in Kazakhstan. Embasaurus was named by Riabinin in 1931. The type species is E. minax. This is a dubious genus because of the sparse fossils.


An embryo is a very young, unborn organism. Some fossilized dinosaur embryos have been found.


Enantiornithes (meaning "opposite birds") were a group of toothless birds that evolved during the Cretaceous period. They ranged in size from a few inches to the size of a vulture. They evolved alongside modern-day birds, but were an evolutionary dead-end. Their name, meaning "opposite birds," refers to the fact that their shoulder blade (scapula) and coracoid (a small bone connected to the scapula) are oriented opposite to that of modern birds. Some Enantiornithes genera include Eoalulavis, Gurilynia, Lingyuanornis, Alexornis, Kizylkumavis, Lenesornis, Sazavis, Iberomesornis, and others.


An endocast is the cast of a brain, taken from the cranial cavity of a skull.


The endocranial cavity is the area within the skull where the brain and other tissue are located.


Endotherms maintain a relatively constant internal temperature. Endothermic animals generate their own body heat to maintain their body temperature, which is usually higher than that of the surroundings. Heat from the bloodstream circulates through the body in order to maintain the animal's temperature. Birds and mammals are endothermic.


(pronounced ee-NIG-moh-SAWR-us ) Enigmosaurus (meaning "mystery lizard") was a huge meat-eating dinosaur from the late Cretaceous period. This bipedal predator was about 21-23 ft (6.5-7 m) long; it was an advanced theropod, a Therizinosaur. Only a partial pelvis of Enigmosaurus was found in Mongolia. The type species is E. mongoliensis. Enigmosaurus was named by Barsbold and Perle in 1983.


(pronounced en-TELL-oh-dons) Entelodonts (meaning "perfect teeth") were huge, ancient mammals that lived in Mongolia, Asia, and in North America. These four-legged, cloven-hooved, omnivores (eating both plants and meat) may have been scavengers. These artiodactyls (relatives of modern-day pigs and hippos) were about 7 feet tall at the shoulder. They had protective bony lumps on the face, relatively short legs, a big skull, a long snout, and large, thickly-enameled teeth in large jaws. Entelodonts lived from 45 until 25 million years ago.


Eoalulavis was the earliest bird that had good maneuverability while flying, even at low speeds (this extra flight control is obtained from a tuft of feathers on the thumb called the alula - it also helps in takeoffs and landings). Fossils of this extinct bird have been found in Spain. (Class Aves)


(pronounced EE-oh-BRON-toh-SAWR-us) Eobrontosaurus (meaning "dawn thunder lizard") was a huge plant-eating dinosaur from the late Jurassic period.. This long-necked, whip-tailed, small-headed quadruped was very similar to Apatosaurus (the original Brontosaurus), but slightly more primitive. It was a diplodocid sauropod. A partial fossil was found in Wyoming, USA. The type species is E. yahnahpin (Filla, James & Redman, 1994). Eobrontosaurus was named by American paleontologist Robert Bakker in 1998.


(pronounced EE-oh-SER-ah-tops) Eoceratops (meaning "dawn horn face") was an early ceratopsian dinosaur. This ceratopsid had a short frill and three short horns on its face. It had a large skull, four sturdy legs with hoof-like claws, a bulky body and a short, pointed tail. It lived during the late Cretaceous period. This dubious genus may have been an ancestor of Triceratops or it may be a juvenile Chasmosaurus. Fossils have been found in North America. Eoceratops was named by Canadian paleontologist L. Lambe in 1915. The type species is Eoceratops canadensis. For more information, see Chasmosaurus.


Eohippus (meaning "dawn horse") is the genus of the earliest-known horse. Another name for this genus is Hyracotherium. It dates from the early Eocene Epoch and lived in the Northern hemisphere (Asia, Europe, and N. America). It was 2 feet (60 cm) long and 12-14 inches high at the shoulder (the size of a small dog!). It had a long skull with 44 long-crowned teeth (it could only eat soft leaves). It had 4 hoofed toes on the front feet and 3 hoofed toes on each hind foot. Family Equidae.


(pronounced EE-oh-LAMB-ee-ah) Eolambia (meaning "dawn lambeosaurine"; lambeosaur were crested duckbill dinosaurs) was a plant-eating dinosaur from the middle Cretaceous period. This is the earliest-known hadrosaur (duckbill) but not the most primitive (which is Protohadros). Fossils were found in Utah, USA. Eolambia was named by paleontologist Kirkland in 1998. The type species is E. caroljonesa.


(pronounced EE-oh-MY-ah) Eomaia (meaning "dawn mother") is the earliest-known primitive placental mammal (or an ancestor of placental mammals). This tiny, shrew-like mammal lived 125 million years ago, during the early Cretaceous period. Its total length was 6 inches ( a 3-inch tail plus a 3-inch body). Eomania walked on four legs and had clawed feet -- it could probably climb trees. Although its teeth were like those of placental mammals, itt had an epipubic bone (a characteristic of marsupials) Eomania was an insectivore. A fossil was found in China's Liaoning province. The type species is E. scansoria.
Eon Time
Phanerozoic Eon 540 million years ago through today
Proterozoic Eon 2.5 billion years ago to 540 million years ago
Archaeozoic Eon 3.9 to 2.5 billion years ago
Hadean Eon 4.6 to 3.9 billion years ago


Two or more geological eras form an eon, which is the largest division of geological time, lasting hundreds of millions of years.


(pronounced EE-oh-RAP-tor) Eoraptor is the oldest known dinosaur. It was a bipedal plant-eater from 228 million years ago (during the late Triassic period).


Eosuchians (meaning "early crocodile") were reptiles that evolved during the late Triassic period, about 220 million years ago. These lizard-like diapsids probably gave rise to lizards and snakes. They walked on four sprawling legs and had a very long tail - some lived in the water (like Hovasaurus). Fossils of Eosuchians have been found in Southern and south-eastern Africa and Madagascar. The newly-found bipedal Eudibamus was an Eosuchian. Other Eosuchians include Thadeosaurus and Hovasaurus. Classification:Class Reptilia, Subclass Diapsida, Order Eosuchia.


Eotitanosuchids (meaning "giant dawn crocodiles") were enormous primitive therapsids that lived during the middle Permian period (about 267 to 265 million years ago, long before the dinosaurs evolved). These land-dwelling meat-eaters (carnivores) were up to about 20 ft (6 meters) long, weighing up to 500 kg. The skull was up to 1 m long. Eotitanosuchids were top predators of their time (they had no natural enemies). Eotitanosuchids had long, massive canine teeth and a short snout. They probably preyed upon large plant-eaters like Estemmenosuchus and perhaps some large marine animals. Some Eotitanosuchids include Eotitanosuchus (Chudinov, 1960), Ivantosaurus (Chudinov, 1983), and Kamagorgon (Tatarinov, 1999). Fossils have been found in eastern European Russia. The family Eotitanosuchidae was named by Chudinov in 1960.


Eotyrannus (meaning "dawn tyrant" or "early tyrant") was a dinosaur that was about 15 ft (4.5 m) long. This theropod (bipedal meat-eating dinosaur) lived during the middle Cretaceous period, about 120 to 125 million years ago; it was a relative of T. rex. A 40 perent complete fossil was found in 1997 on the Isle of Wight, off the coast of Great Britain. The type species is Eotyrannus lengi (named to honor Gavin Leng, who found the first fossil on the Isle of Wight). Eotyrannus was found by a team headed by Darren Naish (Univ. of Portsmouth).


Eozostrodon was one of the first true mammals; it lived during the late Triassic period and early Jurassic period, about 210 million years ago. This small, primitive, egg-laying mammal fed the young with mother's milk. Eozostrodon was a quadruped with short legs, a long, pointed snout, five-toed feet with claws, and a long, hairy tail (it looked like a modern-day shrew). Eozostrodon was about 42 inches (107 cm) long. It was a triconodont that belonged to the family Morganucodontidae, which had true mammalian teeth (the cheek teeth were differentiated into simple premolars plus more complex molars, and the teeth were replaced only once, and the molars had triangular cusps).


(pronounced ee-PAK-tho-SAWR-us) Epachthosaurus (meaning "ponderous lizard") was a huge plant-eating dinosaur from the late Cretaceous period, about 87.5 million years ago. This titanosaurid (armored sauropod) had a long neck, long tail, small head, and heavy body. It was about 50-65 ft (15-20 m) long. A partial fossil was found in Argentina. Epachthosaurus was named by J. Powell in 1990. The type species is E. .


(pronounced ee-pan-TEER-ee-as ) Epanterias (meaning "buttressed," referring to the vertebrae) was a huge meat-eating dinosaur from the late Jurassic period. It was rounghly 35 ft (11 m) long and may have weighed 3-5 tonnes. Fragmentary fossils were found in western North America. Epanterias was named by paleontologist Cope in 1878. Epanterias may be the same as Allosaurus amplexus . It was originally thought to be a giant plant-eater, a sauropod.


The epoccipital is a bone edging the frill of certatopian dinosaurs.


An epoch is a division of a geologic period; it is the smallest division of geologic time, lasting several million years.


The EQ (encephalization quotient) is the ratio of the brain weight of the animal to the brain weight of a "typical" animal of the same body weight. This measure was developed by the Harry J. Jerison in the 1970's. This helps determine the relative intelligence of extinct animals. Dromaeosaurid dinosaurs had the highest EQ among the dinosaurs.
Equisetum (a modern genus of horsetail) is a primitive, spore-bearing plant (a sphenopsid) with rhizomes. Its side branches are arranged in rings along the hollow stem. Other genera of horsetail were common during the Mesozoic Era, like Neocalamites, Calamites etc. Horsetails date from the Devonian period 408-360 million years ago, but are still around today and are invasive weeds.


(pronounced EK-wiss) The modern horse (genus Equus, which also includes zebras, asses, etc.) evolved about 4 million years ago in North America. It spread to Asia, Europe and Africa. The North American horses went extinct about 8,000 years ago, probably because of disease.


Two or more geological periods comprise an Era, which is hundreds of millions of years in duration.
(pronounced ee-REK-toh-pus) Erectopus (meaning "upright foot") was a meat-eating dinosaur. A theropod, it weighed about 450 pounds (200 kg). This therizinosaur had long hands with short claws (perhaps with five fingers). It lived during the early Cretaceous period, about 113-97.5 million years ago in what is now northern France, Egypt, and Portugal. Only a partial skeleton has been found. Erectopus was named by von Huene in 1922. The type species is E. sauvagei.


"Eric" is a 85 percent complete opalized leptocleidine pliosaur (a marine reptile) from the early Cretaceous in Australia (it was named to honor Eric Idle of Monty Python, the television comedy show). Eric the pliosaur was a marine carnivore (meat-eater) that was about 6.5 ft (2 m) long. Fish back bones (and gastroliths) were found in the stomach area of this fossil, so it likely ate small fish, catching them in its crocodile-like jaws.
(pronounced ER-lik-oh-SAWR-us) Erlikosaurus (meaning "Erlik's lizard"; Erlik is the king of the dead in Mongolian myths) was a meat-eating dinosaur. This theropod was about 16-20 ft (5-6 m) long and lived during the late Cretaceous period. Fossils of this . therizinosaur have been found in Mongolia. Only a partial skeleton (including a skull) has been found. Erlikosaurus was named by Barsbold and Perle in 1980. The type species is E. andrewsi.


(pronounced EAR-ee-ops) Eryops (meaning "long eye" or "drawn-out eye" in Greek) was a common, primitive labyrinthodontid amphibian that lived in Permian period swamps. This meat-eater had a stout body with very wide ribs, a strong spine, four short, strong legs, a short tail, and a wide, elongated skull with many sharp teeth. Its teeth had enamel with a folded pattern. Eryops was about 5 feet (1.5 m) long, one of the largest land animals of its time. Eryops was a fierce predator on land and in the water; it may have eaten mostly fish, small reptiles and amphibians. It may have been preyed upon by Dimetrodon, which was a faster moving animal. Eryops may have been slow moving on land. Fossils have been found in Texas, USA. Eryops was named by E. D. Cope in 1887.
(pronounced ee-RITH-row-SOOK-us) Erythrosuchus (meaning "red crocodile") was a large, meat-eating thecodont (a socket-toothed reptile). It was not a dinosaur, but was closely related to them. Erythrosuchus had long, stong jaws and ate plant-eaters, like dicynodonts. It lived during the late Triassic period, about 220 million years ago. Fossils were found in South Africa. Erythrosuchus was named by R. Broom in 1905.


The esophagus is the tube from the mouth to the stomach.


(pronounced es-TEM-en-oh-SOOK-us) Estemmenosuchus (meaning "crowned crocodile") was a large, quadrupedal animal about 13 feet (4 m) long and over 6.5 feet (2 m) tall. It was not a dinosaur. This plant-eater had long, sharp, forward-pointing teeth in the front of the mouth and smaller cheek teeth at the sides; these teeth let Estemmenosuchus eat a wide variety of tough plant material (like cycads, horsetails, and conifers). Estemmenosuchus had a massive skull, a short tail, and a bulky body. The thick skull had many bony knobs: two by the nostrils, two in the middle of the snout, and two moose-like "horns" over the eyes. Fossilized skin shows a smooth, scaleless texture. Estemmenosuchus' predators may have included Eotitanosuchids and Brithopodids.This dicynodont therapsid (sometimes called mammal-like reptiles) lived during the late Permian period (roughly 255 million years ago, before the dinosaurs evolved). Fossils have been found in eastern Russia. Estemmenosuchus was named by P.K.Chudinov in 1913.


(pronounced you-BRONT-tees) Eubrontes giganteus is a dinosaur known only from its fossilized, three-toed footprints, an ichnogenus. Eubrontes means "true thunder." The sandstone tracks range from 10-16 inches (25.5-41 cm) long and they are spaced 3.5-4.5 feet (1-1.4 m) apart. These sizes indicate that the dinosaur who made the prints was about 5 feet (1.5 m) tall at the hip (about the size of Dilophosaurus). The shape and pattern of the prints indicate that it was a theropod, a bipedal meat-eater. The tracks date from about 200 million years ago, during the early Jurassic period. Eubrontes trackways were found in Connecticut, USA. Geologist Edward Hitchcock named them in 1845. No fossilized bones have been found in the vicinity, but over 2,000 tracks have been uncovered in what is now Dinosaur State Park. Eubrontes is the state fossil of Connecticut.
(pronounced you-SEE-loh-FIE-sis) Eucoelophysis (meaning "true hollow form") was a meat-eating dinosaur. It was about 8-10 ft (2.5-3 m) long and weighed about 33-66 pounds (15-30 kg). This coelophysoid theropod lived during the late Triassic period in what is now New Mexico, USA. Only partial skeletons have been found. Eucoelophysis was named by Sullivan and Lucas in 1999. The type species is E. baldwini.


Eudibamus cursoris was a small, fast-moving lizard that lived during the Permian period, roughly 290 million years ago. It is the earliest-known animal that walked on two legs (it was facultatively bipedal; it ran on two legs when it needed to). Eudibamus' hind legs were long, and its front legs were short and weak (the hind legs were 64% longer than the front legs and 34% longer than its trunk). It also had a long tail. This plant-eater used its speed to avoid its predators. It was 10.3 inches (26.1 cm) long. David Berman (of the Carnegie Museum of Natural History) estimated that Eudibamus could run about 15 miles per hour (24 kph). Fossils of this synapsid were found in a quarry near Gotha, Germany, in 1993. Eudibamus was named by Robert Reisz, et al. Eudibamus was not a dinosaur, but another, much earlier type of reptile. Dimetrodon was a contemporary of Eudibamus. Classification: class Reptilia (reptiles), order Eosuchia, suborder Bolosaurida, family Bolosauridae, Genus Eudibamus, species E. cursoris.
Eudimorphodon (meaning "true two-form tooth") was a pterosaur with a 2.5 feet (0.75 m) long wingspan, with large eyes, a short neck, many sharp teeth in pointed jaws (for eating fish and insects), and a diamond-shaped flap of skin at the end of the long, pointed tail. From what is now Italy during the late Triassic period. It was not a dinosaur, but type of extinct, flying reptile. It was named by Zambelli in 1973


(pronounced you-HEL-oh-pus or YOU-hel-OH-pus) Euhelopus (meaning "good marsh foot") was a camarasaurid sauropod from the late Jurassic period, about 156 to 150 million years ago. This plant eater had a very longneck, a bulky body, a long tail and a small, boxy head with spoon-shaped teeth. Its front legs and hind legs were almost the same size. It was about 34 ft (10 m) long; the neck alone was about 16 ft (5 m) long. Euhelopus weighed about 20 to 24 tons. Euhelopus was found in Shandong, China. It was named by Romer in 1956. The type species is E. zdanskyi.


(pronounced you-NOTE-oh-SAWR-us) Eunotosaurus africanus Seeley was a tortoise-like reptile (not a dinosaur). This amniote dates from 250 million years ago. Its poorly-preserved fossils show that it had 8 ribs and the beginning of a shell (the lower shell was not found and the damaged skull yielded few details). Eunotosaurus may be an ancestor of the mdern-day turtle. It was a parareptilian descended from Cotylosaur. Its fossil has been found in South Africa.


(pronounced YOU-oh-plo-SEF-ah-lus) Euoplocephalus was a heavily armored, plant-eating dinosaur from the late Cretaceous period, about 76-70 million years ago. It was about 20-23 feet (6-7 m) long and about 5.8 feet (1.7 m) wide. This solitary animal had a bony tail-club and armor covering most of its body. Fossils were found in Alberta, Canada. Euoplocephalus was named by paleontologist Lambe in 1910.


Euparkeria was a small, early, land-dwelling archosauriform (a reptile closely related to the archosaurs; Euparkeria was a branch off the evolutionary tree very soon before the emergence of dinosaurs). This fast-running quadruped had a semi-erect posture; it could walk on four legs, the front limbs were much shorter than the hind limbs, indicating that it may have been able to run bipedally for short distances. This carnivore (meat-eater) had a long tail, four-fingered hands, large, flexible jaws and many sharp, serrated teeth in sockets. It was about 1.5 ft (0.5 m) long. Euparkeria dates from the early Triassic period, about 225 million years ago. Fossils have only been found in southern Africa.


Eupatagus antillarum is an extinct type of sand dollar about 4-5 inches (12 cm) in diameter. It dates from the Eocene epoch, (about 58-37 million years ago). Many of these fossils have been found in Florida, USA. (Phylum Echinodermata, Class Echinoidea)


Euramerica was the joined continents of Europe and the Americas (during parts of the Mesozoic Era).


Eurasia is the combined, joined land masses of Europe and Asia.
Eurhinosaurus was an Ichthyosaur about 6.5 feet (2 m) long). Unlike other Ichthyosaurs, it had an elongated upper jaw, perhaps used for obtaining food by poking into the sea bed. From what is now Germany during the early Jurassic period. It was not a dinosaur, but another type of extinct reptile.


(pronounced your-on-IK-oh-don) Euronychodon (meaning "Europoean claw-tooth") was a Tetanuran theropod related to Deinonychus. This bipedal meat-eater was perhaps 6.5 ft (2 m) long.z It lived during the late Cretaceous period. This dinosaur is only known from fossil teeth found in Portugal. The type species is E. portucalensis. Euronychodon was named by paleontologists Telles Antunes and Sigogneau-Russell in 1991.


Euryapsids were a group of marine reptiles (now extinct) that had a single skull opening behind the eye socket, a subgroup of the diapsids. Euryapsids include plesiosaurs, nothosaurs, placodonts, and ichthyosaurs.


Eurypterida (meaning "wide wing") are extinct carnivorous marine arthropods (segmented invertebrates with a chitinous exoskeleton and jointed legs), also called "sea scorpions." These hunters had a scorpion-like stinger which may have contained poison, 3 pairs of jointed legs, 2 clawed arms, and strong jaws. Some had two paddles for swimming. They may have swum on their backs. Eurypterids include Eurypterus, Onychopterella, Pterygotus, Mixopterus, Slimonia, Palmichnium (an ichnogenus, i.e., known from fossilized trackways), etc. Eurypterids date from the early Paleozoic Era, arising during the Ordovician period, over 400 million years ago. Many are found from the Silurian period. They went extinct in the Permian mass extinction. Eurypterids are the state fossil of New York.


(pronounced YOO-skel-oh-SAWR-us) Euskelosaurus (meaning "good-limbed lizard") was a plant-eating dinosaur named for its 3 ft (1 m) long thigh bone. This enormous browser was about 30-40 ft (9-12 m) long and may have weighed about 1.8 tonnes. A plateosaurid prosauropod, it lived during the late Triassic period in what is now Lesotho, South Africa and Zimbabwe. Hundreds of fossilized bones have been found. Euskelosaurus was named by Thomas Huxley in 1866. The type species is E. browni.


(pronounced you-SMILE-us) Eusmilus was a saber-toothed cat that lived during the late Eocene (about 40 million years ago) in Eurasia, and spread eastward over the Bering land bridge to North America by the Oligocene Epoch. Fossils have been found in France and the USA (in North Dakota, South Dakota, and Wyoming). This predator had long, saber-like upper canine teeth, but only 26 teeth in its mouth (most carnivores have about 44 teeth). Its huge jaws could open about 90 degrees, allowing it to stab its victims with its incisors. Eusmilus was about 8 feet (2.5 m) long; it had a long, low body and a long tail. Classification: Superfamily Feloidea (cats, mongooses), Family Felidae, Subfamily Machairodontinae, Genus Eusmilus, species cerebralis, etc.


(pronounced you-sthen-OP-ter-on) Eusthenopteron was a large, fleshy-finned bony fish that lived during the late Devonian (over 400 million years ago). Eusthenopteron had characteristics of early tetrapods, and may have been a forerunner of amphibians. Eusthenopteron had pyramidal bones in its paired fins, a structure similar to that of the limb bones in later land animals. Its skull, backbone sructure, and tooth enamel are also very similar to those of land animals. Eusthenopteron was a carnivore (meat-eater) that had a three-pronged tail, an armored head, and a long body. Its paired dorsa (back)l fins and anal fins were set near the tail; the two pectoral fins were near the head and gills. Fossils of this sarcopterygian fish have been found in Europe (Scotland and Russia) and Canada (Quebec). Classification: Class Osteichthyes (bony fish), Subclass Sarcopterygii (fleshy-finned fish), Infraclass Rhipidistia, Order Psteolepiformes (rhipidistians), Genus Eusthenopteron.
(pronounced you-STREP-toh-SPON-dy-lus) Eustreptospondylus (meaning "well-reversed vertebrae") was a Megalosaurid Tetanuran theropod (a large, bipedal meat-eater) about 23-30 ft (7-9 m) long, weighing about 440-550 pounds (200 kg to 250 kg). This predator had a large head, long, sharp serrated teeth, short arms and a primitive hip structure. It lived during the mid-Jurassic period, about 165 million years ago. Incomplete fossils have been found in England. Eustreptospondylus was named by Richard Owen in 1841. The type species is E. oxoniensis, which was named by C. A. Walker in 1964.


Euthecodon is an extinct genus of crocodilian that lived during the Neogene (the middle Miocene, roughly 13-16 million years ago). Fossils have been found in Ombo, Kavirondo Gulf, Kenya, Africa. It was not a dinosaur.


Evolution is a process in which the gene pool of a population gradually (over millions of years) changes in response to environmental pressures, natural selection, and genetic mutations. All forms of life came into being by this process.


To evolve is to develop by the process of evolution, changing in some way as an adaptation to the environment.


An exoskeleton is a tough, structural body armor made of chitin (a type of protein). Arthropods (insects, arachnids, trilobites, crustaceans, etc.) have exoskeletons.


An extensor muscle which straightens out a joint. (Compare with a flexor muscle, its opposite)


An animal species that is extinct has died out. Most animal species that ever existed have gone extinct, including all the dinosaurs.


Extinction is the process in which groups of organisms (species) die out.

An Extinction-Level Event is a catastrophic event (such as a large asteroid or comet hitting the Earth, a large change in the Earth's temperature/sea level, tremendously increased volcanism, etc.) that is capable of causing a mass extinction. This event would greatly damage the ecosphere of Earth, causing many groups of organisms to die.
Dinosaur and Paleontology Dictionary

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