ZoomDinosaurs.com Dinosaur and Paleontology Dictionary

NANOSAURUS (pronounced NAN-oh-SAWR-us) Nanosaurus (meaning "dwarf lizard") was a small bipedal plant-eater from the Jurassic Period (156-145 million years ago). It was about 4 feet long (120 cm) and 1.5 feet tall (46 cm). Nanosaurus is known from a jawbone found in western North America. Nanosaurus was an Ornithischian dinosaur named by paleontologist Othniel C. Marsh in 1877.

NANOTYRANNUS (pronounced NAN-oh-tie-RAN-us) Nanotyrannus (meaning "tiny tyrant") was a bipedal meat-eater, a theropod from the late Cretaceous Period (68-65 million years ago). It was about 16 feet long (5 m), had a large head, long legs with three-toed feet, short arms with two-fingered hands, a short, thick neck, large jaws with sharp teeth, narrow hips, and a slim tail. Nanotyrannus was a tyrannosaurid dinosaur named by paleontologists M. Williams, R. Bakker, and P. J. Currie in 1988 from a skull only 22 inches (57.2 cm) long found in Montana, USA in 1942. It may be a juvenile Tyrannosaurus rex. The only known skull has been CAT-scanned by Bakker. He thinks that Nanotyrannus is an adult, but many other paleontologists, like Thomas D. Carr disagree, and think the Nanotyrannus is a juvenile T. rex.

NANYANGOSAURUS Nanyangosaurus is an iguanodontid dinosaur found in the Sangping Formation of Neixiang, Henan, China. This plant-eating dinosaur lived during the Cretaceous period. Nanyangosaurus zhugeii was named by Xu, Zing, Xi-Jin Zhao, Jun-Chang Lu, Wang-bo Huang, Zhang-Yang Li and Zhi-Ming Dong in 2000, but is unpublished.

NARES Nares are the openings in the skull for the nostrils. (The singular of nares is naris.)

NATURAL SELECTION Natural selection is the process in which some organisms live and reproduce and others die before reproducing. Some life forms survive and reproduce because they are better suited to environmental pressures, ensuring that their genes are perpetuated in the gene pool.

NAUTILOIDS Nautiloids are primitive, thick-shelled, carnivorous marine invertebrates, cephalopod. The shell is divided into chambers. The nautiloid head has well-developed eyes and tentacles that can grasp prey. They swim by jet-propulsion; they squirt water out from the body cavity. They evolved during the Silurian and are still around today, but are uncommon (only a single genus survives). They were most abundant during the Paleozoic Era, roughly 400 million years ago. Some Nautiloids evolved into Ammonoids.

NEOCERATOSAURIA (pronounced NEE-oh-sir-at-oh-SAWR-ee-ah) Neoceratosauria (meaning "new horned lizards") was a group of small to medium-sized meat-eating dinosaurs, most of which had horns on their head. Neoceratosaurs had four fingers on each hand and a bipedal (two-legged) walk. These theropods lived during in Gondwana (the southern continent, which included South America, Africa, India, Australia, and Antarctica) during the early Jurassic period through the Cretaceous period, roughly 180-71 million years ago. The clade Neoceratosauria was named by paleontologists F. Novas in 1991. Some Neoceratosaurs include Ceratosaurus (pictured above), Carnotaurus, Majungatholus, Indosuchus, and many others.

NEOCOMIAN EPOCH The Neocomian epoch was the early (lower) part of the Cretaceous period, about 144 to 127 million years ago.

NEOGENE The Neogene (24 million to 1.8 million years ago) was the later part of the Tertiary Period. It is divided into the Miocene Epoch (24 million to 5 million years ago, when many mammals appeared, including the horses, dogs, bears, South American monkeys, apes in southern Europe, and Ramapithecus; also, modern birds appear) and the Pliocene Epoch (5 million to 1.8 million years ago, when the first hominids (australopithecines) developed, modern forms of whales appeared, and Megalodon swam the seas).

NEOGNATHAE The Neognathae (meaning "new jaw") are birds . They include most flying birds plus swimming and diving birds like penguins. Neognaths evolved during the Late Cretaceous period, about 70 million years ago. They are grouped together taxonomically based on palate (jaw) structure. (Compare to Palaeognathae.)

NEOVENATOR (pronounced NEE-oh-ven-AY-tor) Neovenator (meaning "new hunter") salerii, a 24.5-26 ft (7.5-8 m) long early Cretaceous theropod similar to (but smaller than) Allosaurus was found on the Isle of Wight. It was named by paleontologists Hutt, Martill and Barker in 1996.

NEST Some animals laid their eggs and raised their young in nests. Some fossilized nests have been found, including those of the plant-eating dinosaur Maiasaura.

NOASAURUS (pronounced NOH-ah-SAWR-us) Noasaurus (meaning "N.O.A. [= Northwestern Argentina] lizard") was a small, meat-eating dinosaur from the late Cretaceous period, about 75 to 65 million years ago. This noasaurid theropod was about 6 ft (1.8 m) long. Noasaurus had a sickle-shaped claw on the second toe of each foot; this claw had a very wide range of movement, even wider than that of the dromaeosaurids like Deinonychus. Noasaurus is the earliest-known coelurosaur. Partial fossils were found in Argentina, South America and named by paleontologists Bonaparte and Powell in 1980. The type species is N. leali.

NODOSAURIDS (pronounced NODE-oh-SAWR-ids) Nodosaurids were one division of the ankylosaurs, a group of armored, plant-eating, ornithischian dinosaurs with spikes running along the sides of their bodies, no tail clubs and pear-shaped heads. Acanthopholis, Hylaeosaurus, Minmi, Nodosaurus, Panoplosaurus, and Sauropelta were nodosaurids.

NODOSAURUS (pronounced NODE-oh-SAWR-us) Nodosaurus (meaning "knobby or node lizard") was a nodosaurid ankylosaur, an armored, quadrupedal, tank-like dinosaur. This plant-eater was about 13-20 ft (4-6 m) long. This ornithischian had bony dermal plates covering the top of its body, four short legs, five-toed feet, a short neck, a narrow head with a pointed snout, powerful jaws, leaf-shaped teeth, and a long, clubless tail. It may have had spikes along its sides, but only incomplete fossils have been found. It lived during the early Cretaceous period, about 113-98 million years ago. It ate low-lying plants. Three very incomplete fossils were found in Wyoming and Kansas; no skulls have been found. Nodosaurus was named by paleontologist Othniel C. Marsh in 1889. The type species is N. textilis.

NOMEN DUBIUM A genus (or species) name is described as a nomen dubium if its classification is not certain; it does not fulfill the stringent criteria set by the International Code of Zoological Nomenclature amd mot recognized as as legal scientific name. Often, this is because there is insufficient fossil material available. For example, Acanthopholis, Altispinax, and Trachodon are dinosaur genera, each of which is described as nomen dubium.

NOTHOSAURS (pronounced NOTH-oh-sawrs) Nothosaurs were fish-eating reptiles with four flipper-like limbs. They lived both on land and in the water during the Triassic period. These streamlined swimmers were not dinosaurs. Nothosaurs had webbed feet, and elongated bodies and necks. Nothosaurs (Order Nothosauria) includes the family Nothosauridae (Nothosaurus, Lariosaurus, and Ceresiosaurus) and the family Pistosauridae (Pistosaurus - more like a pleasiosaur).

NOTHRONYCHUS (pronounced noth-RON-e-cus) Nothronychus (meaning "sloth-like lizard") was a theropod dinosaur that lived during the late Cretaceous Period (94-90 million years ago). It was about 4.5 to 6 m long and may have weighed 900 kg. Nothronychus was a therizinosaur; it had a long neck and may have had feathers. Nothronychus is known from roughly half of one fossil skeleton found in New Mexico, USA, North America (this is the first found that was not from Asia). Nothronycus was found by a team of paleontologist led by Doug Wolfe (of the Mesa Southwest Museum in Mesa, Arizona, USA).

NOTHOSAURUS (pronounced NOTH-oh-SAWR-us) Nothosaurus was a nothosaur, a reptile with flipper-like limbs that lived both on land and in the water (like a modern-day seal). It was about 10 feet (3 m) long and had a long, thin, pointed tail with a fin on its upper portion. This tail must have been used for swimming. It had five long, webbed toes. The forelimbs were shorter than the rear limbs. The jaws were long, thin and full of pointed, interlocking teeth (good fish traps). Nothosaurus lived during the entire Triassic period. Fossils have been found in what is now Europe (Germany, the Netherlands, and Switzerland), North Africa, and Asia (China, Israel, and Russia). It was not dinosaur, but another type of reptile. Classification: Order Nothosauria, Family Nothosauridae.

NOTOCERATOPS (pronounced note-oh-SER-a-tops) Notoceratops ("southern horned face") was a ceratopsian (a frilled, horned, quadrupedal, herbivorous dinosaur with a beak) known only from a late Cretaceous (83-73 million years old) jaw bone. It was found in Argentina, South America, and was named by paleontologist Augusto Tapia in 1918.

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