ZoomDinosaurs.com Dinosaur and Paleontology Dictionary

MOA Moas are large, extinct, flightless birds from New Zealand. The oldest-known moa fossils date from 2.4 million years ago. The last of the moa (smaller species) lived on the South Island of New Zealand until the 1700's. Classification: Class Aves (birds), order Dinornithiformes, family Dinornithidae.

MOERITHERIUM Moeritherium is an extinct mammal and may be the ancestor of all elephants. Moeritherium was about 3 ft (1 m) long and weighed about 450 pounds (200 kg), the size of pig. It had a long skull, a short trunk-like upper lip, four powerful legs and big feet. It had primitive teeth that jutted forward and two tusk-like insisors. This swamp dwelling herbivore appeared roughly 53 million years ago, living from the late Eocene until the early Oligocene. Fossils have been found in northern and western Africa. Classification: Order Proboscidea, Suborder Moeritherioides.

MONERA Monera is a prokaryotic kingdom (separate from the plant kingdom) that includes the earliest forms of life on Earth, like archaebacteria (the oldest types of bacteria), eubacteria (like E. coli), and cyanobacteria (blue-green bacteria).

MONOCLONIUS (pronounced mon-oh-KLOHN-ee-us) Monoclonius was a large Ceratopsian dinosaur, a horned, short-frilled, herding herbivore. It was about 16.5 feet (5 m) long, had a large horn on its snout, had 2 small horns near the top of its frill, and had a toothed, horny beak. It had a bulky body, a short, thick, pointed tail, a very large skull. It lived during the late Cretaceous period (76-73 million years ago) and may have roamed in herds. Monoclonius was named by E. Cope in 1876.

MONOLOPHOSAURUS (pronounced MON-oh-LOAF-oh-SAWR-us) Monolophosaurus (meaning "one crest lizard") was a medium-sized meat-eating dinosaur with a single crest on the top of the skull. It was a theropod from the late Jurassic period, about 170 million years ago. This speedy, bipedal dinosaur had long, strong legs, short arms, a large head, and was roughly 16 ft (5 m) long. A partial fossil was found in NW China in 1984. The type species is M. Jiangjunmiaosaurus. Monolophosaurus was named by paleontologists Zhao and Currie in 1993.

MONONYKUS (pronounced mon-NON-ih-kus) Mononykus (meaning "single claw") was a small, insect-eater from the Late Cretaceous period, about 72 million years ago. Mononykus was either a bird-like dinosaur (an advanced theropod) or a primitive bird; it possessed qualities of both groups of animals, and there is some scientific debate over which it is. Mononykus had short arms with one long, thick clawed finger on each hand (hence its name). It was lightly built, had long, thin legs, and a long tail. Mononykus was roughly 28 inches (70 cm long). A fossil was found in SW Mongolia in 1923 (and orginally called Mononychus). Mononykus was named by Perle, Norell, Chiappe, and Clark in 1993. The type species is M. olecranus.

MONOPHYLETIC A monophyletic group consists of all organisms that share a particular common ancestor (and therefore have similar features). The members of a monophyletic group are more closely related to one other than they are to any organism outside the group. A monophyletic group is also called a clade. An example of a monophyletic group is mammals.

MONTANOCERATOPS (pronounced mon-TAN-oh-SER-ah-tops) Montanoceratops (meaning Montanan horned face) was an herbivorous, horned, frilled dinosaur (a ceratopsian) about 10 ft (3 m) long. It had a small horn on its nose and lived during the late Cretaceous period. This dinosaur was named by C. M. Sternberg in 1951. It is known from two partial skkeletons found in Montana, USA. The type species is M. cerorhynchus.

MORGANUCODON (pronounced mor-GAN-ew-KO-don) Morganucodon (meaning "Morgan's tooth") was a small, very early mammal (not a dinosaur). It lived during the late Triassic and early Jurassic periods, about 2oo million years ago. It was about 4 inches (10 cm) long; it had a short tail, large eyes, a long, narrow snout, sharp teeth, and short legs. Morganucodon ate insects and other small animals. Like other primitive mammals, it may have laid eggs. Fossils have been found in China and caves in Wales. Morganucodon was named by F.R. Parrington in 1941.

MOROPUS Moropus was a Miocene mammal (not a dinosaur). It resembled a horse with 3 big claws on each foot. The front feet had longer claws than the hind feet. The claws may have been used for defense or for digging up edible roots. Its back sloped downwards toward the hind legs. It had low-crowned teeth; it probably ate soft leaves rather than tough grass. This 10 ft (3 m) long quadruped was an herbivore that lived in North America. Classification: Order Perissodactyla (odd-toed ungulates), Suborder Ancylopoda, Family Chalicotheriidae.

MORRISON FORMATION The Morrison Formation is a rock outcropping located in Utah, USA. This exposed sedimentary rock dates from the late Jurassic period, when this area was similar to a savanna (without the grass, since flowering plants hadn't evolved yet). Dinosaurs like Allosaurus, Seismosaurus, Ceratosaurus, Ornitholestes, and Diplodocus have been found at the Morrison foundation.

MOSASAUR (pronounced MOES-ah-SAWR) Mosasaurs (meaning "Meuse lizard" named for the Meuse river in Holland where they were first found) were giant, carnivorous marine reptiles (but not dinosaurs) that lived during the late Cretaceous period. They were powerful swimmers that had four paddle-like limbs on a long, streamlined body. The large head had large jaws with many teeth. They hunted fish, turtles, mollusks, and shellfish. Some Mosasaurs include the Mosasaurus (40-59 feet=12.5-17.6 m long with sharp teeth from the North Atlantic), Platecarpus, Tylosaurus (33-40 feet=10-12.3 m long with sharp teeth from the North and South Atlantic), Plotosaurus, Clidastes, Plioplatecarpus, and Globidens (with flat teeth for crushing shellfish). The first Mosasaur, Mosasaurus hoffmani, was found in the Netherlands in 1780.

MOSASAURUS (pronounced MOES-ah-SAWR-us) Mosasaurus was a giant, meat-eating marine reptiles (a mosasaur, not a dinosaur) that lived during the late Cretaceous period. It was up to 40-59 ft (12.5-17.6 m) long. Mosasaurus had four paddle-like limbs on a long, streamlined body and a long, powerful tail. The large head had huge jaws (up to 4.7 ft =1.45 m long) with many teeth. The jaws could open about 3 feet (1 m). The lower jaw is loosely hinged to the skull with a moveable joint on each side (behind the teeth). This loose joint let it swallow huge prey, like some snakes. They hunted fish, turtles, mollusks, and shellfish. Mosasaurus lived in the North Atlantic Ocean. Mosasaurus maximus found in Onion Creek, Texas, USA. It was 30 foot (9 m) long and its tail was about 12 ft (3.7 m) long. This huge reptile was discovered in 1934 by University of Texas geology students Clyde Ikins. The first Mosasaur, Mosasaurus hoffmani, was found in the Netherlands in 1780. It was named in 1822 by W.D. Conybeare. Mosasaurus are related to modern-day monitor lizards.

MOSCHOPS Moschops was a large therapsid, an ancestor of the mammals. It walked on 4 legs; the front legs were sprawling but the rear legs were more column-like. It was about 16 feet (5 m) long. This herding animal had a massive skull and may have engaged in head-butting (like modern-day rams). This plant-eater had chisel-like teeth. Moschops lived during the late Permian period, before the dinosaurs evolved. Fossils have been found in South Africa. Classification: Subclass Synapsida, Order Therapsida (advanced synapsids and ancestors of mammals).

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