ZoomDinosaurs.com Dinosaur and Paleontology Dictionary

GALLIC EPOCH The Gallic epoch was the middle part of the Cretaceous period, about 127 million to 89 million years ago.

GALLIMIMUS (pronounced gal-uh-MIME-mus) Gallimimus (meaning "rooster mimic") was an ostrich-like dinosaur about 17 feet long. This lightly-built, fast-running theropod was a long-beaked omnivore (eating plants and animals) from the late Cretaceous period, about 75-70 million years ago. Gallimimus was found in the Gobi desert in the early 1970's. It was named by paleontologists R. Barsbold, H. Osmólska, and E. Roniewicz in 1972.

GALTON, PETER Peter M. Galton is a British paleontologist working in the USA. He named: Aliwalia (1985), Blikanasaurus (with J. van Heerden, 1985), Bugenasaura (1995), Callovosaurus (1980), Camelotia (1985), Dracopelta (1980), Gravitholus (with W. P. Wall, 1979), Lesothosaurus (1978), Ornatotholus (with H. Sues,1983), Othnielia, (1977), Stygimoloch (with H. Sues,1983), Torvosaurus (with J.A. Jensen, 1979), Valdosaurus (1977), Yaverlandia (1971), and Ruehleia (2001). He named the dinosaur families: Blikanasauridae (with J. van Heerden, 1985), Fabrosauridae (1972), and Staurikosauridae (1977). He named the order Herrerasauria (1985). H3 also championed the cladistic theory that birds are modern-day dinosaurs (with R. Bakker, 1974), showed that Hypsilophodon was not arboreal (did not live in trees), that hadrosaurs did not drag their tails but used the tail as a counterbalance for the head, and that the Pachycephalosaurs butted heads like rams.

GANGLION A ganglion is a mass of nerve tissue outside the central nervous system (in any animal). Some of the larger dinosaurs (some sauropods and Stegosaurus) may have had a ganglion at the base of the tail.

GASTROPOD (pronounced GAS-troh-pod) Gastropods are a class of mollusks that have a sucker-like foot. These soft-bodied invertebrates include the common garden snail, the sea snail, and the slug.

GASTROLITHS (pronounced GAS-troh-liths) Gastroliths are stones that some animals swallow and use to help grind up tough plant matter in their digestive system. They're also called gizzard rocks.

GEOLOGY Geology is the study of the Earth's structure, including rocks.

GEOLOGIST A geologist is a scientist who studies geology.

GEOSAURUS (pronounced GEE-oh-SAWR-us) Geosaurus (meaning "rock lizard") was an early, aquatic crocodylian about 10 ft (3 m) long. This streamlined fish-eater had a long, pointed jaw with sharp teeth, four fleshy flippers (the rear flippers were considerably longer than the front flippers), and a long tail with a tail fin. Geosaurus was NOT a dinosaur, but was a reptile that lived side-by-side with ichthyosaurs and plesiosaurs in the seas during the late Jurassic period until the early Cretaceous period. Geosaurus fossils have been found in Europe (an especially nice specimen was found in southern Germany) and South Africa. Classification: Subclass Archosaur, Order Crocodylia, Suborder Thalattosuchia, Family Metriorhynchia, Genus Geosaurus. They type species is G. gracilis. Geosaurus was named by F. Cuvier in 1842.

GERANOSAURUS (pronounced JER-an-oh-SAWR-us) Geranosaurus (meaning "crane lizard") was a small, fast heterodontosaurid ornithischian dinosaur from the early Jurassic period, about 208-194 million years ago. This lightly-built plant-eater had fangs and a beak. It is known from an incomplete jaw found in South Africa. The type species is G. atavus; Geranosaurus was named by Broom in 1911. This is a dubious genus.

GERROTHORAX Gerrothorax was a larval-like amphibian that lived during the late Triassic period. This aquatic animal was about 3 ft (1 m) long. It looked like a large tadpole with a flattened body, a short, wide head, two small, close-set eyes, small, webbed, hind limbs, and a small tail. It had 3 pairs of gills throughout its life, so it could live in the water even as an adult. This carnivore (meat-eater) lived in streams and lakes. Fossils have been found in Sweden. Gerrothorax was not a dinosaur. Classification: Subclass Labyrinthodontia, Order Temnospondyli, Genus Gerrothorax

GERTIE Gertie was the first animated dinosaur. Gertie was drawn by the newspaper cartoonist Winsor McCay, beginning in 1913. McCay drew Gertie because his fellow cartoonist, George McManus, bet him that he couldn't. Gertie was based on the sauropod Brontosaurus (now known as Apatosaurus). McCay's short animated film, called Winsor McCay America's Greatest Cartoonist and Gertie, was released in 1914 and was a great success. In the movie, Gertie eats a tree, drinks a lake, dances on two legs, plays, and gives McCay a ride. The film consists of 10,00 drawings.

GIANT GROUND SLOTH Megatherium (pronounced MEG-ah-THEER-ee-um) was the largest giant ground sloth; its name means "great beast." Megatherium was a huge, bulky, slow-moving herbivore (plant-eater) with peg-like teeth, powerful jaws, and a thick, short tail. This ice-age mammal had three hook-like claws on each hand. It was primarily a quadruped (walked on four legs). It may have eaten leaves from the tops of trees while standing upright on its hind legs, using its tail to balance. Megatherium was the size of an elephant. It lived during the Pleistocene epoch in what is now South America, going extinct about 11,000 years ago. It was about 20 feet (6 m) long and weighed roughly 3-4 tons. Megatherium was named by R. Owen in 1856; the first Megatherium fossil was found in Brazil in 1789. (Cohort (many grouped orders) Edentata, Family Megatheriidae, Genus Megatherium)

GIANT SQUID The giant squid (Architeuthis) is the largest squid and the largest invertebrate (animal without a backbone). It has not been seen alive since it lives very deep in the oceans. The largest-known Architeuthis was 57 feet (17.5 m) long. It has eight arms plus two longer 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.

GIGANOTOSAURUS (pronounced JIG-ah-NOT-oh-SAWR-us) Giganotosaurus (meaning "giant southern reptile") was one of the largest meat-eating dinosaurs. This theropod was slightly longer than T. rex. It was about 43 ft (13 m) long and weighed roughly 8 tons. It lived during the mid-Cretaceous period, about 100-95 million years ago. Its fossil was unearthed in the Patagonia region of Argentina (in southern Argentina) in 1994.

GIGANTOPITHECUS Gigantopithecus (meaning "gigantic ape") was the biggest primate that ever lived. Gigantopithecus was a gorilla-like land-dwelling ape that weighed roughly 650 pounds (300 kg) and was about 10 feet (3 m) tall. It was an omnivore, probably eating eating plants and small animals. This intelligent mammal lived during from the late Miocene until the middle Pleistocene, roughly a million years ago. Some people think that some surviving specimens of Gigantopithecus are the Yeti of the Himalayas. Fossils (mostly jaws and teeth) have been found in China, India, and Pakistan. Gigantopithecus was named by the German paleoanthropologist Ralph von Koenigswald; in the 1930's, he had spotted huge fossilized teeth being sold in Hong Kong for medicinal purposes. The type species is Gigantopithecus blacki (named to honor Koenigswald's colleague Davidson Black).

GIGANTOTHERMY (pronounced jie-GANT-oh-therm-ee) Gigantothermy is the maintenance of a constant, relatively high body temperature by having a large body and insulation. Large animals have a relatively low surface area: volume ratio, so they retain heat better than smaller animals.

GIGANTSPINOSAURUS Gigantspinosaurus (meaning "giant-spined lizard") was a stegosaurid dinosaur, a large plant-eater with bony plates running along its back and tail. This ornithischian dinosaur lived during the Jurassic period. Fossils of a nearly-complete Gigantspinosaurus skeleton were found in Zigong , China. Gigantspinosaurus was excavated in 1985 and named in 1993, but the author is uncertain, and Gigantspinosaurus is considered a nomen nudem (newly named with little available information). The type species is G. sichuanensis.

GINKGO or GINGKO Ginkgo or Gingko (also called the maidenhair tree) is a primitive seed-bearing tree (a gymnosperm) that was common during the Mesozoic Era, but has only one existing species now. Ginkgos peaked during the Jurassic and Cretaceous periods. This deciduous (losing its leaves in cold weather) tree has fan-shaped leaves divided into two lobes. Classification: Division Pinophyta (Gymnosperms) , Subdivision Pinicae, Class Pinopsida, Order Ginkgoales, Family Ginkgoaceae (Ginkgo).

GIRAFFATITAN (pronounced ji-RAFF-ah-TIE-tan) Giraffatitan, 75-100? feet (23-30 m) long, was a huge, lightly-built, quadrupedal, long-necked, whip-tailed, plant-eating dinosaur from the late Jurassic period. It was a brachiosaurid sauropod from Tendaguru, Tanzania, Africa. Giraffatitan, meaning "gigantic giraffe," was named by paleontologist Gregory S. Paul in 1988. G. brancai is the type species.

GIZZARD The gizzard (also called the gastric mill) is the part of the stomach that grinds up food (usually tough plant material), often aided by gizzard rocks. Many birds have a gizzard, as did some dinosaurs.

GIZZARD ROCKS Gizzard rocks are stones that some animals swallow and use to help grind up tough plant matter in their digestive system. They're also called gastroliths.

GLOSSOPTERIS Glossopteris (from the Greek glossa, meaning tongue, because the leaves were tongue shaped) is a genus of extinct seed fern (a Pteriosperm) whose fossils are found throughout India, South America, southern Africa, Australia, and Antarctica. Glossopteris was about 12 ft (3.6 m) tall. The distribution of this fossil plant throughout the southern hemisphere led the Austrian geologist Eduard Suess to deduce that there had once been a land bridge between these areas. He named this large land mass Gondwanaland (named after a district in India where the plant Glossopteris was found). This was the southern supercontinent formed after Pangaea broke up during the Jurassic period. It included what are now the continents South America, Africa, India, Australia, and Antarctica. These deciduous (losing their leaves in the cool season) gymnosperms arose during the late Permian period and became dominant, but went extinct by the end of the Triassic period.

GLYPTODON Glyptodon (pronounced GLIP-toh-don) was the one of the biggest ancient armadillos (the family Glyptodontidae). This car-sized herbivore (plant-eater) was well-armored, having dome-shaped body armor, helmet-like head armor, and rings of bony armor on its short tail. This mammal had four short, thick legs; the front feet each had five clawed toes and the rear feet were more hoof-like. It had a short snout and powerful jaws, with no teeth in the front and grinding teeth farther back in the jaws. It was about 10 feet (3.3 m) long and 5 feet (1.5 m) tall. Fossils have been found in Argentina, South America. It lived during the Pleistocene (between 2 million and 15,000 years ago). Glyptodon (meaning "carved tooth") was named by paleontologist R. Owen in 1839.

GLYPTODONTID The family Glyptodontidae were ancient armadillos (about 50 genera) that lived during the Pliocene through the Pleistocene. These extinct, armored mammals had four short legs, powerful jaws, with no teeth in the front and grinding teeth farther back in the jaws. The glyptodontids ranged from to 10 feet (3.3 m) long and 5 feet (1.5 m) tall. Fossils have been found in North America and South America. These herbivores (plant-eaters) may have been preyed upon by saber-toothed cats. Some glyptodontids included: Glyptodon (the biggest) and Doedicurus (pictured above).

GOJIRASAURUS (pronounced go-JEER-a-SAWR-us) Gojirasaurus (meaning "Godzilla lizard") was a meat-eating dinosaur over 18.3 ft (5.5 m) long (it is the biggest-known theropod of its time). This biped lived during the late Triassic period. Fragmentary fossils of this ceratosaur were found in New Mexico, USA. Gojirasaurus was named by paleontologist Carpenter in 1997. The type species is G. quayi.

GOMPHOTHERIUM Gomphotherium was a 4-tusked, primitive mastodont that was about 10 ft (3 m) tall. This plant-eater mammal lived during the early Miocene until the early Pliocene (roughlty 24 to 5 million years ago). This elephant-like mammal had a long trunk, relatively small ears, a short tail, and four column-like legs. It had a long lower jaw with two parallel tusks. Fossils have been found in Kenya (Africa), France (Europe), Pakistan (Asia), and Kansas, USA (North America). Classification: Class Mammalia, Order Proboscidea, Suborder Elephantoidea, Genus Gomphotherium.

GONDWANALAND Gondwanaland, also known as Gondwana, was the southern supercontinent formed after Pangaea broke up during the Jurassic period. It included what are now the continents South America, Africa, India, Australia, and Antarctica. Gondwanaland was named for a district in India where the fossil plant Glossopteris was found; this plant led E. Suess to deduce that the southern continents were once joined, supporting Wegener's continental drift theory

GORGOSAURUS (pronounced GORE-goh-SAWR-us) Gorgosaurus (meaning "Gorgon lizard") used to be thought to be an invalid name for Albertosaurus, but is now believed to be a separate genus of tyrannosaurids. Gorgosaurus was named by Paleontologist L. Lambe in 1914. It was a large, meat-eating dinosaur, a theropod about 26-30 feet (8-9 m) long. This fierce predator had a large head with many sharp teeth, tiny arms, large powerful legs, and a stiff tail. Over 20 incomplete fossilized skeletons have been found in Alberta, Canada and Montana, USA. This relatively intelligent dinosaur dates from the late Cretaceous period, roughly 76 to 68 million years ago. The type species is G. libratus.

GOUT Gout is a metabolic disease in which excess uric acid crystallizes, scars bones and joints, and causes pain. Gout has been found in T. rex fingers.

GOYOCEPHALE (pronounced GOH-yoh-SEF-ah-lee ) Goyocephale (meaning "elegant or decorated head") was a thick-skulled, flat-headed, plant-eating dinosaur with knobs and spikes on its pitted skull and large teeth. It dates from the late Cretaceous period, about 85 to 80 million years ago. This homalocephalid pachycephalosaur was found in Mongolia (the skull and parts of the skeleton were found). Goyocephale was named by Perle, Maryanska and Osmolska in 1982. The type species is G. lattimore.

GRADE A grade (also called a paraphyletic group) consists of a common ancestor and some, but not all, of its descendants. These are incomplete groups based primarily on physical characteristics rather than directly on evolutionary relationships. An example of a paraphyletic group is the dinosaurs (without including the birds).

GRAZING FOOD CHAIN The grazing food chain is a model that describes the flow of organic energy through organisms in an ecosystem. A trophic level is a level of this grazing food chain. For example, plant-eaters are primary consumers; they occupy the second trophic level in the grazing food chain.

GRENDELIUS Grendelius was a lage ichthyosaur, an extinct aquatic reptile. This carnivore lived dring the late Jurassic period. Like all ichthyosaurs, they gave birth to live young. They had a long, toothed snout and a fish-like tail that moved like that of a modern-day fish. Fossils have been found in the U.K.

GRESSLYOSAURUS (pronounced GRES-lee-oh-SAWR-us) Gresslyosaurus was quadrupedal plant-eating dinosaur that lived during the late Triassic period. This 23 feet (7 m) long dinosaur ate leaves high in the trees. Gresslyosaurus means "Gressly's lizard," named to honor the Swiss geologist Amanz Gressly (1814-1865), who coined the term" facies" to describe the aspects (or "faces") of the terrain. Gresslyosaurus was named by Ruetimeyer in 1857 to replace the preoccupied Dinosaurus. Gresslyosaurus is the same genus as Plateosaurus robustus.

GRYPOSAURUS (pronounced GRIP-oh-SAWR-us) Gryposaurus (meaning "hook-nose lizard") was a duck-billed dinosaur from the late Cretaceous period, about 76 to 72 million years ago. This hadrosaurid was a plant-eater that was about 30 feet (9 m) long. It had a long, narrow skull, highly-arched nostrils, and a big bump on its snout. Its skin had 0.25 inch (0.5 cm) wide polygonal scales (shaped like polygons) on its neck, sides and belly. It had 0.5 inch (1.3 cm) wide cone-shaped plates on its tail, spaced about 2-3 inches (5.2-6.8 cm) apart. It is known from a over 10 skulls, some bones, and skin impressions found in Alberta, Canada. Gryposaurus was named by fossil hunter L. Lambe in 1914. The type species is G. notabilis.

GYMNOSPERM Gymnosperms (meaning "naked seeds") are seed-bearing plants that don't produce flowers. They release pollen into the air to the female ovule, causing fertilization. Their seeds develop without a protective covering. The earliest gymnosperms were seed ferns from the Devonian period (408-360 million years ago). Conifers (like pines, redwoods, and fir), gingkos, seed ferns, cycadeoids, and cycads are gymnosperms. These plants were very important to plant-eating dinosaurs.

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