A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Appendix

Macrodontophion

Taxon: possibly Theropoda

name means: “long-toothed snake”

pronounced: MACK-roh-DON-tuh-FEE-on

size: Unknown

time: Late Jurassic or Early Cretaceous

place: Ukraine

Macrodontophion as a genus is based only upon a single slender, recurved tooth. Named by Zhorzewski in 1834, this animal has been described as a meat-eating megalosaurid, but some experts say that the barely-tapering tooth may not have come from a dinosaur at all.

Macrophalangia

Name means: “long toes”

Pronounced: MAK-ro-fa-LAN-jee-a

This dinosaur is now known as CHIROSTENOTES.

Macrurosaurus

Taxon: Sauropoda Titanosauridae

Name means: “long-tailed lizard”

Pronounced: mack-ROOR-uh-SAW-rus

size: 40 ft (12 m)

Time: Early Cretaceous, 138 – 95 mya

Place: England

One of the first titanosaurs ever found, this four-legged plant-eater is known mostly from fossilized tail vertebrae. 19th Century paleontologist Harry Govier Steely estimated that the tail of this browser alone may have been more than 15 feet long.

Magnosaurus

Taxon: Theropoda

Name means: “large lizard”

Pronounced: MAG-nuh-SAW-rus

size: Large

Time: Late Jurassic, 188 – 175 mya

Place: England

Information about this large meat-eating theropod is sketchy. It may have belonged to the Megaolosauridae, a group of large, carnivorous dinosaurus, but had a more slender look and a differently shaped pubis and tibia than others of that group.

Magyarosaurus

Taxon: Sauropoda Titanosauridae

Name means: “Magyar lizard,” for the Magyar, an ethnic group in Hungary

Pronounced: MAG-yahr-uh-SAW-rus

size: about 16 – 20 ft (5 – 6 m)

Time: Late Cretaceous, 70 – 65 mya

Place: Hungary, Romania

A member of the titanosaurids, a group of large, sometimes armored, plant-eating sauropods, Magyarosaurus had slender limbs. But scientists know little more about the creature. Fossils assigned to the species may belong to several different kinds of dinosaur, each found in the Transylvanian area

Maiasaura

Taxon: Ornithopoda Hadrosauridae

Name means: “good mother lizard”

Pronounced: MYE-uh-SAW-ruh

Size: 30 ft (9 m)

Time: Late Cretaceous, 77 – 73 mya

Place: Montana

Dr. John R. Horner has made his career, in part, by studying this remarkable hadrosaur and the bone beds from which so many of its fossils have sprung. Maiasaura was a plant-eating “duckbilled” dinosaur, with a wide face and a short horny beak. Its skull was large, about 32 inches long. Horner found the skeletal remains of eleven Maiasaurua babies, each just over three feet long, clustered together in a nest-like setting. He discovered four more babies just seven feet from the nest. Horner also found thousands of fragments of fossilized eggshell as well as intact, unhatched Maiasaura eggs. Based on his studies, Horner believes that Maiasaura lived in huge herds or nesting groups. Just 13 inches long when they hatched, juvenile Maiasaura reached a length of ten feet by the end of their first year. Such rapid growth suggests a quick metabolism, supporting the theory that at least some dinosaurs were warm-blooded like modern birds and mammals. Because the tiny hatchlings appear to have been helpless to move around or forage for food on their own, parents or siblings may have had to care for the young until they were able to leave the nest and join the herd. The study of these fascinating animals has helped to revolutionize the way that we view dinosaur parenting and physiology.

Majungasaurus

name means: “Majunga lizard”

pronounced: mah-JUNG-uh-SAW-rus

This is now known to be the same animal as MAJUNGATHOLUS.

Majungatholus

Taxon: Ceratosauria Abelisauridae

Name means: “Marjunga dome”

pronounced: mah-JUNG-uh-THOH-lus

size: about 23 – 30 feet (7 – 9 m)

time: Late Cretaceous, about 84 – 71 mya

place: Madagascar

When its fragmentary fossil skull, featuring a prominent dome-like forehead thickening ornamented by bone furrows and nodes, was first discovered, Majungatholus was taken for a member of the dome-headed pachycephalosaurs. The recent discovery of a second, more complete skull, as well as a skeleton, has revealed that this was actually a meat-eating abelisaurid theropod, related to Carnotaurus and Abelisaurus. The function of the unusual lump of forehead bone remains a mystery.

Malawisaurus

Taxon: Sauropoda Titanosauridae

Name means: “Malawi lizard”

Pronounced: mah-LAH-wee-SAWR-us

Length: Large

Time: Early to Middle Cretaceous, c. 144 – 99 mya

Place: Malawi, Africa

This long-necked, plant-eating sauropod, scientifically described in 1993, was named

for the country of Malawi in southern central Africa where it was discovered.

Maleevosaurus

Taxon: Tyrannosauridae

Name means: “Maleev’s lizard,” for Evgenii Aleksandrovich Maleev

Pronounced: MAH-lee-AY-vuh-SAW-rus

Length: Moderate

Time: Late Cretaceous, 75 – 70 mya

Place: Mongolia

Named by Ken Carpenter, this member of the tyrannosaurid family was small for its kind. Maleevosaurus is distinguished from most tyrannosaurids through the presence of small openings in its upper jaw, a smooth horn above each eye socket, and a slender lower jaw. Maleevosaurus was once thought to be a juvenile Tyrannosaurus before being placed in its own genus, and some researchers now believe that it may have been a juvenile Tarbosaurus. Ken Carpenter named this dinosaur in honor of Russian paleontologist Evgenii Aleksandrovich Maleev.

Maleevus

Taxon: Ankylosauridae

Name means: “for Maleev,” after Evgenii Aleksandrovich Maleev

Pronounced: MAH-lee-AY-vus

Length: 20 ft (6 m)

Time: Late Cretaceous, 97.5 – 88.5 mya

Place: Mongolia

Another dinosaur named in honor of Russian paleontologist Evgenii Aleksandrovich Maleev, this poorly-known armored ankylosaurid bristled with large side-spikes and lacked a clubbed tail. Maleevus was once believed to be Pinacosaurus.

Mamenchisaurus

Taxon: Sauropoda

Name means: “Mamenchi lizard”

Pronounced: mah-MEN-chi-SAW-rus

Length: 72 – 85 ft (22 – 26 m)

Time: Late Jurassic, 156 – 145 mya

Place: China

Named for the Mamenchi Ferry at the Jiang River in China, this plant-eating sauropod is the longest dinosaur currently known from Asia. Stretching 35 feet, the neck of Mamenchisaurus made up almost half of its entire body length and was the longest of any known dinosaur. Mamenchisaurus is similar in appearance to members of the giant, whip-tailed diplodocid family, but the bones of its foot and ankle resemble those of Tienshanosaurus, and the skull is quite distinctive.

Mandschurosaurus

Taxon: Ornithopoda Hadrosauridae

Name means: “Manchurian lizard”

Pronounced: mand-SHOO-ruh-SAW-rus

Length: 27 ft (8 m)

Time: Late Cretaceous, c. 71 – 65 mya

Place: Manchuria, Russia, China

This hadrosaur may or may not have borne a crest, as a complete skull has yet to be recovered and definitively tied to the genus. Mandschurosaurus, the first dinosaur found in China to be scientifically named, is known mostly from skeletons mounted in museums in Russia and China. Unfortunately, most of the material was collected from mass bonebeds, where the bones of many individual dinosaurs were washed together and mixed up, making it impossible to piece together all the bones of any single individual. The type specimen of this genus appears to be a combination of bones from at least two species of hadrosaur, one with a crest and one without.

Marshosaurus

Taxon: Theropoda

Name means: “Marsh’s lizard”

Pronounced: MAHR-shuh-SAW-rus

Length: 17 ft (5 m)

Time: Late Jurassic, 156 – 145 mya

Place: Utah, Colorado

Recovered in the same rocks which produced fossils of Allosaurus, this meat-eating theropod appears to have had a number of advanced anatomical features. Without additional remains to study, however, further classification will be difficult. Marshosaurus was named in 1976 in honor of the pioneer American paleontologist Othniel Charles Marsh.

Massospondylus

Taxon: Prosauropoda Massospondylidae

Name means: “elongated vertebra”

Pronounced: MAS-oh-SPON-di-lus

Length: 12 - 20 ft (4 – 6 m)

Time: Early Jurassic, 208 – 194 mya

Place: South Africa, Arizona

This slender prosauropod had a small head with large, almost circular eye sockets, sizable nostrils, and relatively large teeth. Massospondylus was named by Owen in 1884. Tragically, the type specimen from which the genus was scientifically described was destroyed in World War II.

Megadontosaurus Invalid name. A mixture of Microvenator and Deinonychus material

Megalosaurus

Taxon: Theropoda Megalosauridae

Name means: “great lizard”

Pronounced: MEG-uh-luh-SAW-rus

Length: about 23 – 33 ft (7 – 10 m)

Time: Middle Jurassic, c. 175 - 155 mya

Place: England, France, possibly Portugal

When Megalosaurus was reconstructed and named in the 1820s, the dinosaur’s body length was greatly exaggerated and estimated at more than 60 feet. Once researchers removed extra bones which turned out not to have belonged to the original animal, its size was revised to a more realistic but still impressive 23 to 26 feet. One of the first dinosaurs to be officially named, Megalosaurus had long, powerful jaws and sharp, double-edged teeth. Its three fingered hands and short forelimbs were stronger than those of many large carnivores, thanks to its hefty upper arms. Those arms are just one of the physical features which show Megalosaurus to be a more primitive theropod than Allosaurus. Unfortunately, as a complete skeleton has yet to be recovered, there remains more to be learned about this important dinosaur.

Megaraptor

Taxon: Theropoda, possibly Coelurosauria

Name means: “big plunderer”

Pronounced: meg-a-RAP-tor

Length: about 20 – 26 ft (6 - 8 m)

Time: Late Cretaceous, 94 – 86 mya

Place: Argentina

This large, recently-discovered predator has been described as a giant Deinonychus-like dromaeosaurid with enormous 15-inch-long slashing claws. In the absence of a skull, however, and given the dinosaur’s coelurosaur-like foot proportions, it is difficult to classify Megaraptor with absolute certainty.

Melanorosaurus

Taxon: Prosauropoda Melanorosauridae

Name means: “Black Mountain lizard”

Pronounced: muh-LAN-oh-ruh-SAW-rus

Length: 40 ft (12 m)

Time: Late Triassic, 228 – 219 mya

Place: South Africa

Unlike most of its group, this early plant-eating prosauropod probably walked exclusively on all fours. It is considered to have been one of the heaviest prosauropods, and resembles the larger sauropods with its small head, long neck and tail, powerful legs and thick, sturdy skeleton.

Metriacanthosaurus

Taxon: Theropoda

Name means: “moderate spine lizard”

Pronounced: MET-ree-uh-KAN-thu-SAW-rus

Length: 26 ft (8 m)

Time: Late Jurassic, 160 mya

Place: England

Date: 1964

This large carnivore appeared to be so similar to Megalosaurus that it was at first believed to be a new species of that genus. Metriacanthosaurus is now distinguished by the high spines of its backbone. These spines were about ten inches long, twice as high as the vertebrae themselves, and when covered with muscle tissue in life, they would have given the dinosaur a distinctively hump-backed appearance. Metriacanthosaurus was named in 1964.

Microceratops

Taxon: Ceratopsia Protoceratopidae

Name means: “small horned face”

Pronounced: MYE-kroh-SER-uh-tops

Length: 30 in (76 cm)

Time: Late Cretaceous, 83 – 65 mya

Place: China

This tiny ceratopsian probably closely resembled the primitive horned dinosaur Protoceratops. Lightly-built and with a short neck frill, Microceratops had long hind limbs which suggest that it could have run on two legs when speed was of the essence.

Microcoelus

Name means: “small hollow”

Pronounced: MYE-kroh-SEE-lus

This dinosaur is now known to be SALTASAURUS.

Microhadrosaurus.

Taxon: Hadrosauridae

name means: “ small hadrosaur”

Pronouncd: MYE-kroh-HAD-ruh-SAW-rus

size: 9 ft (3 m)

time: Late Cretaceous

place: China

Based on a jaw fragment and named for its tiny teeth, this small plant-eating “duckbilled” hadrosaur may have actually been a juvenile Edmontosaurus.

Micropachycephalosaurus

Taxon: Pachycephalosauridae

Name means: “small pachycephalosaurid”

Pronounced: MYE-kroh-PACK-I-SEF-uh-loh-SAW-rus

Length: 1.6 – 2 ft (50 – 60 cm)

Time: Late Cretaceous, 83 – 73 mya

Place: China

A tiny thick-skulled plant-eater discovered in China, this specimen is one of only two pachycephalosaur species known from that country. Although one of the smallest known dinosaurs, Micropachycephalosaurus has the longest scientific name to date.

Microsaurops

Name means: “small lizard face”

Pronounced: MIKE-ro-SAWR-ops

A small, poorly-known possible titanosaurid.

Microvenator

Taxon: Theropoda

Name means: “small hunter”

Pronounced: MYE-kroh-vi-NAY-tor

size: 4 ft (1.2 m)

Time: Early Cretaceous, 119 – 113 mya

Place: Montana

This small theropod probably weighed less than 15 pounds and appears to have been a fully-grown adult. It may have been closely related to primitive caenagnathids, related to the ostrich-like dinosaurs. Microvenator was named by John Ostrom in 1970.

Minmi

Taxon: Ankylosauria

Name means: “Minmi”

Pronounced: MIN-mee

Length: 10 ft (3 m)

Time: Early Cretaceous, 119 – 113 mya

Place: Australia

Like all of the armored nodosaurids, Minmi lacked the clubbed tail of true ankylosaurs. Unusually small for its group, this sturdy four-legged plant-eater had bony armor on its belly, a characteristic so far unique among the armored dinosaurs. Minmi is the only ankylosaurid known from Australia to date.

Mochlodon

Name means: “barred tooth”

Pronounced: MOCK-luh-don

This dinosaur is now known as RHABDODON.

Mongolosaurus

Taxon: probably Sauropoda

name means: Mongolian lizard

pronunciated: mong-GOH-luh-SAW-rus

size: Large

time: Early Cretaceous

place: Mongolia

Little is known about this apparent sauropod, and what we do know is based on its fossilized teeth. Unlike those of most sauropods, the teeth of Mongolosaurus were tapered and set in the jaw at an obtuse angle. They resemble the teeth of Diplodocus with a few differences, including the serrated borders of the crown. Some researchers suggest that Mongolosaurus is actually a segnosaur rather than a sauropod.

Monkonosaurus

Taxon: Stegosauridae

Name means: “Monko lizard”

Pronounced: monk-OH-no-SAW-rus

Length: 17 ft (5 m)

Time: Late Jurassic, Early Cretaceous, 150 – 138 mya

Place: Tibet

Monkonosaurus was Tibet’s first dinosaur discovery. First thought to be a bone-headed pachycephalosaur, this medium-sized plant-eating stegosaur with back plates similar to those of Stegosaurus was discovered in and named for Monko County in Tibet.

Monoclonius

Taxon: Ceratopsidae

Name means: “single sprout”

Pronounced: MON-uh-KLOH-nee-us

Length: 17 ft (5 m)

Time: Late Cretaceous, 76 – 73 mya

Place: Montana, Alberta

One of the then-mysterious horned ceratopsians, Monoclonius proved to be a puzzle for paleontologists of the mid-1870s. Incorrectly described as a hadrosaur based on a misplaced row of teeth, the dinosaur was soon properly recognized and reclassified by Cope. The nose horn of Monoclonius was excluded in descriptions until 1889, when the true arrangement of ceratopsian horns and frills had become better understood. Recently, several researchers have suggested that some or all Monoclonius specimens may actually be juvenile members of other ceratopsian species.

Monolophosaurus

Taxon: Theropoda

Name means: “single crest lizard”

Pronounced: MON-uh-LOH-fuh-SAW-rus

Length: 16 ft (5 m)

Time: Late Jurassic, 170 mya

Place: China

Once informally known as “Jiangiunmiaosaurus,” this medium-sized carnivorous dinosaur had a large skull with a distinctive semicircular crest above the snout and eyes. Some paleontologists suggest that this unusual structure served as a perhaps brightly-colored display to attract mates or to establish territorial dominance.

Mononychus

Name means: “one claw”

Pronounced: mo-NO-ni-kus

The name of this dinosaur was changed to MONONYKUS.

Mononykus

Taxon: probably Metornithes

Name means: “one claw”

Pronounced: mo-NO-ny-kus

Length: 3 ft (1 m)

Time: Late Cretaceous, c. 90 – 65 mya

Place: Mongolia

This species has inspired great debate within the paleontological community. A wingless, birdlike animal whose short, stubby arms each end in a powerful, curved claw, Mononykus is considered by some researchers to have been a theropod related to the ancestors of birds. Others argue that Mononykus was actually a primitive bird whose flying ancestors returned to a ground-based lifestyle – a theory strengthened by the recent discovery of a very birdlike skull for the animal. The unique claws and heavily-muscled arms of this dino-bird or bird-dino may have been used for digging or for tearing bark to reach a hidden meal of insects.

Montanoceratops

Taxon: Ceratopsia Protoceratopidae

Name means: “Montana horned face”

Pronounced: mon-TAN-o-SER-ah-tops

Length: 6 ft (2 m)

Time: Late Cretaceous, 73 – 70 mya

Place: Montana

Named by Sternberg in 1951, this small horned dinosaur resembles the more primitive Protoceratops. Compared to that relative, Montanoceratops had a larger, stockier snout equipped with a nose horn, longer forelimbs, and a generally more massive skeleton. It is considered to be more advanced, or specialized, than Protoceratops.

Morinosaurus

Taxon: Sauropoda

name means: “Morini Lizard”

Pronounced: muh-REE-noh-SAW-rus

Size: Large

Time: Late Jurassic

Place: France

This poorly-known sauropod, named for an ancient people of northern France, was likely a member of the giant brachiosaurid family. Identified by a very worn tooth and part of an upper forelimb bone, Morinosaurus may have resembled Hypselosaurus.

Morosaurus

Name means: “stupid lizard”

Pronounced: MOR-uh-SAW-rus

This dinosaur is considered to be CAMARASAURUS.

Mussaurus

Taxon: Prosauropoda Plateosauridae

Name means: “mouse lizard”

Pronounced: MOO-SAW-rus

Length: about 16 in (40 cm) - juvenile

Time: Late Triassic, 215 mya

Place: Argentina

This tiny juvenile prosauropod was described from the smallest non-embryonic dinosaur skeleton discovered so far. The individual was very young and had probably died not long after hatching. The skull of this young Mussaurus was only about 1 ¼ inches long, roughly the length of a quarter.

Muttaburrasaurus

Taxon: Ornithopoda Iguanodontidae

Name means: “Muttaburra lizard”

Pronounced: MUT-uh-BUR-uh-SAW-rus

Length: 24 ft (7 m)

Time: Early Cretaceous, 113 – 97.5 mya

Place: Australia

A large iguanodontid with a distinct bump on its nose, Muttaburrasaurus was named for the township of Muttaburra in Queensland, Australia. The dinosaur seems to have eaten plants, but based on its unusual shearing teeth, it is possible that this species might have consumed meat. Some researchers suggest that Muttaburrasaurus may have actually been a camptosaurid.

Mymoorapelta

Taxon: Ankylosauria, probably Nodosauridae

Name means: “Mygatt-Moore shield”

Pronounced: mie-MOHR-a-PEL-ta

Length: 9 ft (2.7 m)

Time: Late Jurassic, 154 – 151 mya

Place: Colorado

An armored ankylosaurid dinosaur, Mymoorapelta was named after the Mygatt-Moore Quarry of western Colorado. The genus was scientifically described in 1994.