Dacentrurus

Taxon: Stegosauridae

Name means: “very spiky tail”

Pronounced: DAY-sen-TROO-rus

Length: 15 ft (4.4 m)

Time: Late Jurassic, 163 – 150 mya

Place: England, Portugal, France

Though the plant-eating Dacentrurus had the same general proportions as the 25-foot-long Stegosaurus, its plate and spine configuration was quite different. Dacentrurus carried two rows of small plates and two rows of long, paired spines along its back. Where the plates ended and the spikes began is uncertain, due to limited fossil evidence. A Dacentrurus egg was apparently discovered in Portugal. Dacentrurus was named in 1902 by Lucas to replace Omosaurus.

Dachongosaurus

Taxon: Possibly Sauropoda

name means: “Chinese lizard”

pronounced: duh-CHONG-uh-SAW-rus

size: Large

time: Jurassic

place: China

Very little is known about this large herbivore. It has not yet been officially described in scientific reports. Speculation based on the incomplete skeleton (vertebrae, ribs and limb bones) suggests it may have been a two or four legged prosauropod, or a large four-legged grazing sauropod.

Damalasaurus

Taxon: Sauropoda

name means: “Chinese or Mongolian lizard”

pronounced: DAM-uh-luh-SAW-rus

size: Large

time: Middle Jurassic

place: China

Another large, plant eating, four-legged sauropod, Damalasaurus has not yet been officially described by Chinese paleontologists, and therefore very little about the dinosaur is currently known. It may have been a primitive brachiosaur or close relative.

Dandakosaurus

Taxon: Probably Theropoda

Name means: “Hindi lizard”

Pronounced: dan-DACK-uh-SAW-rus

size: Unknown

time: Early Jurassic

place: India

Dandakosaurus was announced as a new carnosaurian dinosaur, but very little is presently known about the genus. It was reportedly a large carnivore similar to Sinosaurus, a primitive ten-foot-long meat-eater.

Daptosaurus.

Now considered to be DEINONYCHUS.

Daspletosaurus

Taxon: Tyrannosauridae

Name means: “frightful lizard”

pronounced: das-PLEE-tuh-SAW-rus

Length: 25 – 30 ft (8 – 10 m)

Time: Late Cretaceous, 76 – 72 mya

Place: Alberta

This enormous carnivorous biped may have been a direct ancestor, or at least a close relative to the ancestor, of Tyrannosaurus rex. With its large head and low horns above its eyes, it had an especially ferocious appearance. Because its vertebrae were shorter and higher, it would have a stockier neck and trunk than its regional contemporary, Albertosaurus. Named in 1970 by Dale Russell.

Datousaurus

Taxon: Cetiosauridae

Name means: “chieftain lizard” or “big head lizard”

Pronounced: DAH-too-SAW-rus

Length: over 50 ft (15 m)

Time: Middle Jurassic, 170 million years ago

Place: China

This huge primitive sauropod was not only long, but also solidly built. Its skull was large and heavy in comparison to other sauropod heads, with nostril openings in the front rather than on top. Its teeth were large and spoon-shaped. Datousaurus limbs were equally robust, making this four-legged plant eater especially bully, although some researchers question if the head and body, which were found separately, actually belong to the same specimen. Named by Don & Tang.

Deinocheirus

Taxon: Theropoda, possibly Ornithomimidae

Name means: “terrible hand”

Pronounced: DYE-no-KYE-rus

Length: Large

Time: Late Cretaceous, 75 – 65 mya

Place: Mongolia

The only part of this animal which has been found so far is its sizeable forelimb and sharp, strong claws, comprising an arm some 8 feet in length. Based on the three, long, slender fingers, Deinocheirus was probably a meat-eating theropod of considerable size and power. Due to limb similarities, some paleontologists believe that the dinosaur was a gigantic ornithomimid, or ostrich-mimic dinosaur. If so, it would have towered over all other known members of that group. Because the claws have some similarities to those of modern sloths, other scientists speculate Deinocheirus may have used them to pull down trees. Named by Osmolska and Roniewicz.

Deinodon

Taxon: Theropoda

name means: “terrible tooth”

pronounced: DYE-nuh-don)

size: Unknown

time: Late Cretaceous

place: Montana

Named by Leidy in 1856 based on a scattering of carnivorous teeth, this dinosaur may actually be two distinctive species. Dr. F. V. Hayden found the teeth and recognized them as the first tyrannosaurid finds of North America. Some of the teeth were bladelike in shape, much like Megalosaurus. Some were just described as “peculiar.” Whether or not they belonged to the same dinosaur was never completely clear. In time, the bladelike teeth were assigned to Deinodon. The “peculiar” teeth were said to be those of Aublysodon. But without more information from new specimens, details might never be clear.

Deinonychus

Taxon: Dromaeosauridae

Name means: “terrible claw”

Pronounced: diy-NON-i-kus

Length: 10 ft (3 m)

Time: Early Cretaceous, 119 – 93 mya

Place: Montana, Oklahoma, Wyoming, Utah,

Named for the deadly, razor sharp claw on the second toe of its hind foot, Deinonychus

was an important dinosaur find. At 10 feet long, estimated at just under 200 pounds, this

predator was born to hunt. The strong, lean back legs were relatively short for a small

theropod, and suggest that Deinonychus was not as fast as its closest relatives. Long,

muscular forelimbs and three-fingered hands gave it the ability to grip its prey. A long,

stiff tail made it simple to balance while running, kicking or leaping. The ripping claw

on the second toe of its back foot made Deinonychus a capable killer. This enlarged,

five-inch talon was held off the ground while walking and could be deployed in a

powerful slashing kick. The discovery of Deinonychus in 1964 literally changed the

direction of dinosaur science. Dinosaurs were suddenly more than great, stupid, sluggish

lizards. They were also quick, agile hunters, perhaps even warm-blooded and smart.

Like other maniraptorian theropods, Deinonychus is believed to be closely related to the

ancestors of birds. It possessed a light skeleton, large eyes and a relatively big (for a

dinosaur) brain. Recent discoveries in related species indicate that maniraptorians may

have had feather-like coverings or decoration. There is fossil evidence to suggest (but

not prove) that Deinonychus might have hunted and fed in packs. The dinosaur was

officially named in 1969 by John Ostrom.

Deltadromeus

Taxon: Theropoda, possibly Coelurosauria

Name means: “delta runner”

Pronounced: DEL-ta-DROHM-ee-us

Length: 26 ft (8 m)

Time: Late Cretaceous, c. 99 – 65 mya

Place: Africa

This fearsome African meat-eater was named for the river-delta location where it was fossilized and for the strength evident in its powerful hind limbs. Named by Chicago paleontologist Paul Sereno in 1996, Deltadromeus at first seemed to be about the size of an Allosaurus, roughly 30 feet long, but the measurement may be revised.

Dianchungosaurus

Taxon: Unknown

name means: “Central Yunnan (in China) lizard”

pronounced: DYE-an-CHUNG-uh-SAW-rus

size: Unknown

time: Early Jurassic

place: China

Only fossil fragments have been found to help identify this early ornithischian, or bird-hipped dinosaur, so details are limited. It appears to have been a small plant-eating dinosaur with a thin jaw --- toothless in the front, but lined with small rounded teeth in the back. The nostrils seem to have been large and low. The primitive Dianchungosaurus was named for the Dianzhong Basin in central Yunnan Province, China.

Diclonius

Taxon: Hadrosauridae

name means: “double sprout”

pronounced: dye-KLOH-nee-us

size: Unknown

time: Late Cretaceous

place: Montana

Cope named this plant-eating hadrosaur in 1876, based on a double row of fuctional teeth in its jaws. But in the years that followed, he often contradicted his original description, calling the teeth Hadrosaurus/Monoclonius-type teeth. He even re-used the name for a well-preserved flat-headed hadrosaur which is now known as Anatotitan. Today, the teeth that first inspired the name are not considered unique enough to merit creation of a distinct dinosaur species, and the name is largely disregarded.

Dicraeosaurus

Taxon: Sauropoda

Name means: “forked lizard” or “bifurcated lizard”

Pronounced: Dye-KREE-uh-SAW-rus

Length: 13 m (45 feet)

Time: Late Jurassic, 156 – 150 mya

Place: Tanzania, East Africa

This medium sized sauropod had a short neck and an almost hump-backed spine. It fed on plants, like all sauropods, and had relatively short front legs --- roughly 3/5 the length of its back legs. It had a long, tapering tail that it may have used like a bullwhip against predators. Named by Janensch.

Dilophosaurus

Taxon: Ceratosauria

Name means: “double-crested lizard”

Pronounced: dye-LOH-fuh-SAW-rus

Length: 20 – 23 ft (6 – 7 m)

Time: Early Jurassic, 208 – 194 mya

Place: Arizona, perhaps Connecticut

Made famous (or infamous) by Steven Spielberg’s Jurassic Park, this crested theropod was actually 20 feet long and did NOT have an umbrella-like neck frill for display, nor did it spit poison. It did have longer forelimbs than other carnivores of its time. Slender teeth and a relatively weak jaw suggest that Dilophosaurus did not go after very large prey, and the dinosaur likely was a scavenger when the opportunity presented itself. Trackways in Arizona suggest that groups of Dilophosaurus may have traveled in packs.

Dinheirosaurus

Taxon: Sauropoda Diplodocidae

Name means: “Dinheiro lizard” or “Porto Dinheiro (in Portugal) lizard”

Pronounced: deen-YAR-o-SAW-rus

Length: Large

Time: Late Jurassic, c. 159 – 144 mya

Place: Portugal

Bonaparte and Mateus named Dinheirosaurus in 1999, based on fossil material originally attributed to the plant-eater Lourinhasaurus in 1998. In some ways, including the shape of its cervical and dorsal vertebrae, this sauropod was like Diplodocus. But other details suggest the two animals were quite different, and some experts say they are simply two different species with similar traits. Until the two are carefully compared, it will be hard to say for certain.

Dinosaurus

Name means: “terrible lizard”

Pronounced: DYE-nuh-SAW-rus

Time: Late Cretaceous

place: India

Two dinosaurs have been given the genus name “Dinosaurus.” The first turned out to be a Plateosaurus. The second was comprised of a few fossilized remnants of what appears to be a large meat-eater. Identified by Pidancet and Chopard and described as a megalosaurian, this second Dinosaurus was described based only on a large tail vertebra and some fragmentary ribs. The five-inch-long vertebrae suggest this mysterious dinosaur was heavy and large, but information on the animal as a whole is very sketchy. Neither Dinosaurus is presently considered to hold the name officially.

Dinotyrannus

Taxon: Tyrannosauridae

Name means: “terrible tyrant”

Pronounced: DINE-o-tee-RA-nus

size: Unknown

time: Late Cretaceous

place: North America

Little is known about this bipedal theropod, which was named (by Olshevysky, Ford and Yamamoto) for carnivorous features similar to those found in Tyrannosaurus and Nanotyrannus.

Diplodocus

Taxon: Sauropoda Diplodocidae

Name means: “double beam”

Pronounced: di-PLOH-duh-kus

Length: 88 feet (27 m)

Time: Late Jurassic, 156 – 145 mya

Place: Colorado, Utah, Wyoming, Montana

At 88 feet long, the plant-eating Diplodocus is one of the largest dinosaurs ever unearthed. It stands as a typical, graceful four-legged sauropod of the middle dinosaur times. A long, outstretched neck helped Diplodocus to feed on conifers, cycads, ginkgoes and ferns. Diplodocus had an elongated snout and bore nostrils on the top of its head. It had peglike teeth at the front of its mouth, and it probably used them like a comb to rake leaves from branches. Diplodocus had no teeth towards the rear of its mouth, but a crop of rounded stones inside its body may have helped to grind and mash plant material into easily-digested pulp. Half of the dinosaur’s length was made up by its neck and tail. The long, barrel-like midsection may have helped the mighty sauropod to lash its incredibly long, thin tail like a bullwhip to ward off attacking predators. Some scientists believe the Diplodocus anatomy enabled it to rear up on hind legs to reach better food, or to defend itself more easily against predators. Diplodocus was named by Marsh.

Diplotomodon

Taxon: Theropoda

name means: “double cutting tooth”

pronounced: DIP-loh-TOH-muh-don

size: Unknown

time: Late Cretaceous

place: New Jersey

This species replaced the prior genus Tomodon and was named by Leidy. It was a large, meat-eating dinosaur with a strange, bladelike tooth, originally misidentified as the tooth of a marine reptile or plesiosaur, and later as a fish. Upon closer study, it was clear that the tooth most resembled those of Dryptosaurus, another carnivorous dinosaur species. Whether Diplotomodon was actually a member of Dryptosaurus remains uncertain.

Dolichosuchus

Taxon: probably Theropoda

name means: “long crocodile”

pronounced: DOL-I-kuh-SOOK-us

size: Unknown

time:Late Triassic

place: Germany

Very little is known about this early dinosaurian meat eater. Only a partial and imperfectly preserved hind leg distinguishes it from the fossils of other early meat-eaters. Based on the leg bone, which was about 11 inches long, Dolichosuchus was probably a medium sized theropod.

Dracopelta

Taxon: Ankylosauria Nodosauridae

Name means: “dragon shield”

Pronounced: DRACK-uh-PEL-tuh

Length: about 6.5 ft (2 m)

Time: Late Jurassic, 156 – 150 mya

Place: Portugal

Named by Galton, the four-legged, plant-eating Dracopelta was the first Late Jurassic ankylosaur, or armored dinosaur, to be discovered. It was a wide, stocky armored species with at least five distinct kinds of armor on its body, ranging from very small bony bumps to longer plates, ranging from 1 inch by 1 inch to 8 inches by 4 inches.

Dravidosaurus

Taxon: probably Stegosauria

Name means: “Dravid lizard,” after the Dravidanadu region in India

Pronounced: druh-VID-uh-SAW-rus

Size: 10 ft (3 m)

Time:Late Cretaceous

Place: India

The last of the plated stegosaurs, this plant-eating quadruped was much smaller than its cousin, Stegosaurus. It had a long (7.6 inch), narrow skull and a pointed beak. One tooth specimen from Dravidosaurus was similar to the African stegosaur, Kentrosaurus. Dravidosaurus plates were triangular, about 1.5 inches high and 1 inch long.

Drinker

Taxon: Ornithopoda

Name means: “for Drinker,” after Edward Drinker Cope

Pronounced: DRING-kur

Length: 6.5 ft (2 m)

Time: Late Jurassic, 156 – 145 mya

Place: Wyoming

A team of four paleontologists named this little-known plant-eater after Edward Drinker Cope, one of the two men largely responsible for the onset of the dinosaur bone wars of the early 20th Century, a fierce competition to collect and document dinosaur species. Drinker was an ornithischian dinosaur with leaf-shaped teeth and may have been related to Othnielia.

Dromaeosaurus

Taxon: Dromaeosauridae

Name means: “running lizard” or “swift-foot lizard”

Pronounced: DROH-mee-uh-SAW-rus

Length: 6 feet (1.8 m )

Time: Late Cretaceous, 76 – 72 mya

Place: Alberta, Montana

This fleet-footed predator stood four feet tall, with a large head and sharp, serrated teeth. Dromaeosaurus was similar to other small meat-eaters of the time except for an especially large brain cavity, indicating it might have been a particularly smart carnivorous dinosaur. A number of bird-like features in Dromaeosaurus (and related maniraptorian dinosaurs) led many researchers to believe it was closely related to the feathered Archaeopteryx, more bird than reptile. Like its relatives, including Deinonychus and Velociraptor, Dromaeosaurus may have hunted in packs.

Dromiceiomimus

Taxon: Ornithomimidae

Name means: “emu mimic”

Pronounced: droh-MEE-see-uh-MYE-mus

Length: 12 feet (3.6 m)

Time: Late Cretaceous, 75 – 70 mya

Place: Alberta

This long-legged, ostrich-like dinosaur was likely one of the fastest ever to run the earth. Its efficient body was built for speed, which may have surpassed even that of the modern ostrich (over 40 mph). No less impressive would have been the creature’s agility. With nothing but swiftness and sharp vision as defense mechanisms, Dromiceiomimus must have depended on these features to escape larger meat-eaters. Judging from the Dromiceiomimus braincase, it may have been one of the more intelligent dinosaurs of its size. A horny beak suggests Dromiceiomimus might have fed on insects, lizards, mammals, or a variety of plants, while relatively weak jaws and grasping hands meant that the eggs of other dinosaurs might have made an ideal meal. Perhaps most notable of all is the speculation regarding the reproduction of Dromiceiomimus. Some scientists have theorized that the wide pelvic opening means that this fast, clever dinosaur gave birth to live young rather than laying eggs. And because one Dromiceiomimus dig site yielded both adult and juvenile specimens, it’s possible that they lived together in pack or family units. Dromiceiomimus was named by Dale Russell.

Dryosaurus

Taxon: Ornithopoda Dryosauridae

Name means: “tree lizard”

Pronounced: DRYE-uh-SAW-rus

Length: 10 – 12 feet (3 – 3.5 m)

Time: Late Jurassic, 156-145 mya

Place: Wyoming, Colorado, Utah, East Africa

This slender, primitive bipedal dinosaur adapted to feed on even the toughest of Jurassic vegetation. It was likely named “tree lizard” by Marsh in 1894 to support his theory that the species not only used trees and lush vegetation to hide from predators, but to harvest dinner as well. Dryosaurus cheek teeth were long with sharp cutting edges and vertical ridges to make slicing through plant matter more efficient. The almost delicate skeletal proportions suggest that this dinosaur was a quick mover. Dryosaurus remains have been found in both North America and East Africa, indicating that there may have been a connection between the ancient continents at that time before they became fully separated by the slow process of continental drift.

Dryptosauroides

Taxon: probably Theropoda

name means: “Dryptosaurus-like”

pronounced: DRIP-toh-saw-ROI-deez

size: Unknown

time: Late Cretaceous

place: India

Very little is known about this carnivore because only isolated back vertebrae exist to define the species. German paleontologist Friedrich von Huene named it in 1932 because it allegedly resembled the remains of Dryptosaurus. Without more information, more precise details are as hard to unearth as Dryptosauroides fossils themselves.

Dryptosaurus

Taxon: Theropoda

Name means: “tearing lizard”

Pronounced: DRIP-tuh-SAW-rus

Length: 20 feet (6 m)

Time: Late Cretaceous, 70 – 65 mya

Place: New Jersey (Eastern North America)

Dryptosaurus was the first meat-eating dinosaur ever scientifically named and described from North America, and remains to date the only large dinosaurian predator known from eastern North America (although there is some indication that Allosaurus and Dilophosaurus may also have roamed the area). Its most distinctive feature was a large, eagle-like claw that measured nearly 8 inches on the first finger of each taloned hand. The claw may have been used to slice or de-armor its prey. At first called Laelaps when it was described in 1866, this dinosaur was reclassified as Dryptosaurus in 1877 when it was discovered that original name was already in use. Though Dryptosaurus was once seen as a large, meat-eating tyrannosaurid, recent studies suggest that it may have been more like the slender ornithomimid, or ostrich-like, dinosaurs.

Dyslocosaurus

Taxon: Sauropoda Diplodocidae

Name means: “hard-to-place lizard”

Pronounced: diss-SLOH-kuh-SAW-rus

size: 64.5 feet (30 m)

Time: Late Cretaceous, 68 – 65 mya (uncertain)

Place: Wyoming

This long-necked, long-tailed sauropod was relatively slender for its kind, but walked upon amazingly large feet. The toes on the hind feet had a greater circumference relative to their length than those any other diplodocid. The presence of four or even five claws on the usually three-clawed sauropod hindfeet made Dysolocosaurus especially unique. Named by McIntosh, Coombs and Russell, this may have been one of the latest-surviving of all the giant sauropod dinosaurs, although uncertainty as to whether the bones were found in sediment deposits of the Late Jurassic or the Late Cretaceous has made it hard to determine whether it actually was the last diplodocid.

Dystrophaeus

Taxon: Sauropoda

name means: “coarse joint”

pronounced: dis-TROF-ay-us

size: Large

time: Late Jurassic

place: Utah

Dystrophaeus was the first long-necked sauropod dinosaur to be discovered in the New World. Marsh, who named the large animal, theorized that the ends of the limb bones of Dystrophaeus were covered in cartilage even as an adult. In most species, cartilage is only found at the ends of the limbs of still-growing juveniles, so its presence in adults suggests that the plant-eater continued to grow throughout its entire life. It has been suggested that Dystrophaeus may actually be a species of Diplodocus or Barosaurus.

Dystylosaurus

Taxon: Sauropoda, either Brachiosauridae or Diplodocidae

Name means: “double beam lizard”

Pronounced: die-STYE-luh-SAW-rus

Length: Large

Time: 156 – 145 mya

Place: Colorado

Yet another four-legged sauropod collected by Brigham Young University’s Dinosaur Jim Jensen, this large plant-eater had especially long front legs and might have resembled Brachiosaurus. Recent research, however, has suggested that known Dystylosaurus remains may not represent a distinct genus at all, but rather are part of a huge Supersaurus skeleton found near the same site at Colorado’s Dry Mesa quarry.