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

Hadrosauravus

Name means: “bulky lizard bird”

Pronounced: HAD-ro-sawr-AVE-us

Considered to be GRYPOSAURUS.

Hadrosaurus

Taxon: Hadrosauridae

Name means: “bulky lizard”

Pronounced: HAD-ro-SAWR-us

Length: 25 ft (7 m)

Time: Late Cretaceous, 76 – 73 mya

Place: New Jersey

Calling this huge herbivorous dinosaur “Hadrosaurus,” or “bulky, stout lizard,” must have seemed especially appropriate when Joseph Leidy named it in 1858. Previously, all duckbilled dinosaurs were known as Trachodon, meaning “rough-toothed,” and this more descriptive name for a new duckbilled genus seemed ideal. As it turned out, however, Hadrosaurus was only a moderately large and not especially bulky dinosaur species compared to its contemporaries. Hadrosaurus was one of the earliest dinosaurs to be named in North America. Its nearly complete skeleton was discovered on a farm in Haddonfield, New Jersey. Leidy at first believed that Hadrosaurus was an amphibious animal, alternating between browsing for plants on land and swimming in the watery depths. He pioneered the idea that dinosaurs walked on two legs in an upright position.

Halticosaurus

Taxon: Saurischia

name means: “nimble lizard”

pronounced: HAWL-ti-koh-SAW-rus

size: about 18 ft (5.5 m)

time: Late Triassic

place: Germany

This early, slender carnivore is poorly understood. Halticosaurus had a relatively large head, and its foot bones suggest that it was a theropod, perhaps closely related to Rioarribasaurus. The status of a second species assigned to this genus has been challenged by some paleontologists who believe that the new animal’s hip, leg and vertebral bones indicate that it may have been a small plant-eating prosauropod. Halticosaurus was named by von Huene.

Haplocanthosaurus

Taxon: Sauropoda

Name means: “simple spine lizard”

Pronounced: HAP-loh-KAN-thu-SAW-rus

Length: about 70 ft (21 m)

Time: Late Jurassic, 156 – 145 mya

Place: Colorado

One of the most primitive sauropods known from North America, Haplocanthosaurus was the length of two school buses parked end to end. A pair of well-preserved specimens was unearthed near Canon City, Colorado. Famed bone hunter John Bell Hatcher studied the larger of the two. The Cleveland Museum of Natural History excavated and mounted for display a third, less complete specimen in the same area in 1954. This individual may have been as much as 50% larger than the original two specimens discovered. Originally called “Haplocanthus” (“simple spine”) by Hatcher, the dinosaur’s name had to be changed to Haplocanthosaurus when it was discovered that the first choice had already been scientifically used to describe a prehistoric fish.

Haplocanthus

Name means: “simple spine”

Pronounced: HAP-lo-KAN-thus

Now known as HAPLOCANTHOSAURUS.

Harpymimus

Taxon: Ornithomimosauria

Name means: “Harpy mimic”

Pronounced: HAHR-pee-MYE-mus

Length: 12 ft (3.5 m)

Time: Middle Cretaceous, 119 – 97.5 mya

Place: Mongolia

Harpymimus was one of the most primitive “ostrich-like” dinosaurs known as ornithomimids, Like all ornithomimids, this dinosaur had delicate, three-fingered hands, long-shinned, slender legs adapted for speed, and a number of anatomical features, including beak-like snouts with primarily toothless jaws, resembling those of modern-day flightless ground birds. Unlike most ornithomimids, Harpymimus did have six small, dull teeth located in the front of its jaw. It also had uneven foot bones, proportioned more like those of traditional toothed theropods. These features suggest that Harpymimus may have been an evolutionary bridge between less-specialized carnivores and more typical ostrich-mimics like Gallimimus and Ornithomimus. Like other ornithomimids, Harpymimus probably ate a variety of foods, potentially ranging from small animals to fruits and nuts. Harpymimus was named by Barsbold and Pearle.

Heishansaurus

Taxon: Ankylosauridae

name meansl “Black Mountain Lizard”

Pronounced: Hay-shan-SAW-rus

Size: Unknown

Time:Late Cretaceous

place: China

This plant-eating, armored ankylosaur’s remains were badly crushed in fossilization, so positive identification and description has been difficult. Heishansaurus appears to have had distinctive body armor, with thick, circular bony plates about four inches in diameter. Small surface bone-bumps the size of peas were also found in the distorted and poorly-preserved skeleton. This dinosaur’s teeth were much like those of Pinacosaurus, and it was at one time misidentified as a pachycephalosaur.

Heptasteornis Doubtful name. Originally misidentified as a large owl, this small theropod may be Elopteryx.

Taxon: Theropoda

Name means: “seven towns bird”

Pronounced: hep-TAS-tee-OR-nis

size: Small

time: Late Cretaceous

place: Romania

Found in Transylvania, this small theropod is known only from fragmentary leg bones. It may have been related to the meat-eating Troodon or to the dromaeosaurs. Although Heptasteornis was not a bird, it was misnamed Elopteryx in 1913 by Charles W. Andrews, who thought upon early examination that it was one. In 1975, two other scientists renamed it Heptasteornis under the mistaken belief that the dinosaur was a very large prehistoric owl.

Herrerasaurus

Taxon: Theropoda Herrerasauridae

Name means: “Herrera’s lizard”

Pronounced: huh-RAYR-uh-SAW-rus

Length: about 10 – 16.5 ft (3 – 5 m)

Time: Late Triassic, c. 228 mya

Place: Argentina

Herrerasaurus was named in honor of Don Victorino Herrera, a rancher and guide in Argentina who led paleontologist to the bone beds which yielded the first specimens of this ferocious meat-eater, estimated to have weighed about 400 pounds in life. Double-hinged jaws allowed Herrerasaurus to grip its prey and to swallow huge chunks of meat. Serrated teeth helped it to slice the flesh from a fresh kill. Probably the earliest-known representative of the carnivorous dinosaurs, Herrerasaurus was much more primitive than later predators, as evidenced by anatomical features ranging from five-toed feet to the rectangular shape of its nearly-complete skull.

Heterodontosaurus

Taxon: Heterodontosauridae

Name means: “different toothed lizard”

Pronounced: HET-ur-uh-DON-tuh-SAW-rus

Length: 3 feet (1 m)

Time: Early Jurassic, 208 – 200 mya

Place: South Africa

This small plant-eater, only a little over three feet long, was named for the surprising difference between its unusually long and sharp incisor-like canine and more traditionally herbivorous post-canine teeth. It could run on either two or all four legs and had very large eyes. Its slender hind legs were well-adapted for quick bursts of speed, with a tail for balance during those short sprints. Its front limbs might have helped Heterodontosaurus to dig for roots and insects. The dinosaur’s long, slender fingers may have been used for grasping or tearing. Some scientists suggest that only males of this genus had the enlarged canine tusks from which Heterodontosaurus got its name. It was described in 1962 by Crompton and Charig.

Hironosaurus Invalid name. A large Japanese duckbill, known only from fragmentary fossil remains.

Hisanohamasaurus Invalid name. Unofficially known from sauropod-like teeth.

Histriasaurus

Taxon: Sauropoda, probably Diplodocimorpha

Name means: “Istria lizard”

Pronounced: HIS-tree-uh-SAW-rus

Length: Large

Time: Early Cretaceous, c. 127 mya

Place: Croatia

Found in marine limestone outcrops near the village of Bale in Croatia, this four-legged plant eater was named based on a nearly-complete posterior dorsal vertebra. It is probably related to the sauropod Rebacchisaurus, but is considered to be anatomically more primitive.

Homalocephale

Taxon: Pachycephalosauria Homalocephalidae

Name means: “level head”

Pronounced: HOH-muh-loh-SEF-uh-lee

Length: about 5 – 10 ft (1.5 – 3 m)

Time: Late Cretaceous, 80 – 70 mya

Place: Mongolia

This small, plant-eating pachycepholasaur was named for its flat-roofed skull and is one of the best known genera of the thick-headed group. Its skull was 5.5 inches in width and 4.5 inches tall. Small bony knobs were arranged along the edges of its armored skull. Researchers speculate that Homalocephale may have used its flattened skull for head-butting displays, much as bighorn sheep butt horns today. The unusually flattened skull probably helped Homalocephale to distinguish other members of its own species from the dome-headed pachycephalosaurs which lived in the same area.

Honghesaurus

Considered to be YANDUSAURUS.

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Hoplitosaurus

Taxon: Ankylosauria Nodosauridae

Name means: “shield-carrier lizard”

Pronounced: huh-PLEE-tuh-SAW-rus

Length: Small

Time: Early Cretaceous, 135 – 119 mya

Place: South Dakota

At least five different kinds of skin armor have been found with the fossilized bones of this sturdy little plant-eater, which stood about four feet tall at the hip. Hoplitosaurus was covered in a highly varied protective layer of bone protrusions, including thin, flat rectangles, round spikes, thick button-shaped spikes, triangular plates and spiny scutes. However, just where the scattered plates were located on the dinosaur’s body in life is uncertain. Scientists first believed Hoplitosaurus to be a stegosaur, but revised their thinking as more information became available. Hoplitosaurus is now known to be a nodosaurid ankylosaur, although some researchers feel that it cannot be distinguished from Polacanthus and should bear that name instead.

Huayangosaurus

Taxon: Stegosauria Huayangosauridae

Name means: “Huayang lizard” or “Sichuan lizard”

Pronounced: hwye-ANG-guh-SAW-rus

Length: 13.5 ft (4 m)

Time: Middle Jurassic, 170 mya

Place: China

This small plant-eating dinosaur is one of the most primitive, best-known of all the stegosaurs. It was adorned with two rows of small, paired heart-shaped plates that were replaced by narrow spikes at the shoulders and decreased in size towards the back of the tail. Four large spines were found at the tip of the tail, perhaps for defensive use. Later stegosaurs had toothless snouts, but Huayangosaurus had not yet lost the seven teeth on each side of its front jaw bone.

Hudiesaurus Invalid name. A large sauropod, named for a distinctively-shaped backbone.

Taxon: Sauropoda

name means: “butterfly lizard”

pronounced: HOO-dye-SAW-rus

size: 96 – 100 ft (29 – 30.5 m)

time: Late Jurassic

place: China

Hudiesaurus is one of the largest sauropods known from China. It was named for a distinctively-shaped backbone. Four serrated, flattened teeth suggest that Hudiesaurus may have resembled Mamenchisaurus. The dinosaur was discovered by a team of Chinese and Japanese scientists.

Hulsanpes

Taxon: Theropoda Dromaeosauridae

Name means: “Khulsan foot,” Named for Khulsan, a Mongolian locality

Pronounced: HOOL-san-pees

Length: Small

Time: Late Cretaceous, 77 mya

Place: Mongolia

Named for (and known only from) its slender, incompletely-preserved foot, Hulsanpes was a thee-toed carnivore which may have been a dromaeosaurid. The claw on the second toe of the foot seems to have been smaller than the other two. Hulsanpes was scientifically described in 1982.

Hunhosaurus

Now considered to be YANDUSAURUS.

Hylaeosaurus

Taxon: Ankylosauria Nodosauridae

Name means: “woodland lizard”

Pronounced: hie-LEE-o-SAWR-us

Length: 13 ft (4 m)

Time: Early to Middle Cretaceous, 135 – 119 mya

Place: England

This armored ankylosaurid was (along with Megalosaurus and Iguanodon) one of the original three animals used to scientifically define the Dinosauria.

Hylosaurus

Taxon: Ankylosauria Nodosauridae

Name means: “woodland lizard” or “ Wealden lizard ”

Pronounced: hye-LAY-uh-SAW-rus

size: 13 ft (4 m)

time: Early Cretaceous

place: England

Named for the Wealden deposits in England’s Tilgate Forest, this nodosaur was an armored dinosaur which, like all nodosaurs, lacked the ankylosaurian tail-club. It was originally thought to have solid plates of armor, but interpretations of the animal’s armored hide have shifted with study.

Hypacrosaurus

Taxon: Ornithopoda Hadrosauridae Lambeosaurinae

Name means: “near-topmost lizard”

Pronounced: hye-PACK-ruh-SAW-rus

Length: 30 ft (9 m)

Time: Late Cretaceous, 72 – 70 mya

Place: Alberta, Montana

This crested duckbilled hadrosaur was similar to Corythosaurus in that it had a helmet-shaped crest. The head-crest of Hypacrosaurus, however, was less-rounded and positioned further forward than that of Corythosaurus, and the skull was shorter with a more narrow muzzle. Nearly forty rows of densely-packed plant-mashing teeth filled the dental batteries, and the snout was tipped by a toothless beak. Hypacrosaurus had a distinctive ridged back with very long neural spines. Barnum Brown gave Hypacrosaurus its name due to its considerable size, as the herbivore stood nearly as tall as the tyrant king, Tyrannosaurus rex. In recent years, excavations in Alberta and Montana have yielded eggs containing the bones of fossilized Hypacrosaurus embryos.

Hypselosaurus

Taxon: Sauropoda

Name means: “high lizard”

pronounced: HIP-sel-uh-SAW-rus

size: 27 ft (8 m)

time: Late Cretaceous

place: France and Spain

This sauropod was relatively small for its kind. Hypselosaurus was originally described as an aquatic animal, possibly a large crocodilian. It had weak, slender teeth and cannonball-shaped eggs. In fact, Hypselosaurus eggs found in 1860 were the first dinosaur eggs ever discovered. Scientists at the time were not sure whether the heavy fossilized eggs had belonged to a dinosaur or to a very large bird.. In 1992, a single Hypselosaurus egg was sold at auction for $11,000.

Hypsibema

Taxon: Hadrosauridae

name means: “high step”

pronounced: HIP-si-BEE-muh

size: Moderate

time: Late Cretaceous

place: North Carolina

Hypsibema was named by Edward Drinker Cope based on a collection of five bones,

including an upper leg and two limb bones, and a “high stepping” metatarsal or toe bone.

It was likely a duckbill of some kind, possibly the same animal as Hadrosaurus, but

positive identification is difficult with so little fossil material to study.

Hypsilophodon

Taxon: Ornithopoda Hypsilophodontidae

Name means: “Hypsilophus tooth” or “high crested tooth”

Pronounced: HIP-suh-LOH-fuh-don

Length: 7.5 ft (2 m)

Time: Early Cretaceous, 125 – 115 mya

Place: England, Spain, Portugal

Alhough Huxley meant to describe only the ridge at the side of Hypsilophondon’s tooth when he named the dinosaur, he inadvertently implied that the tooth itself was tall and crested. The long fingers and toes of this small, fast-moving herbivore, discovered in 1849 on the Isle of Wight, have led one scientist to propose that Hypsilophodon may have been an agile tree-climber. Limb bones suggesting the presence of powerful hind leg muscles were once considered to support this climbing theory, but they may instead have provided the small dinosaur with quick bursts of ground speed. Armor found near Hypsilophodon fossils may have been part of the dinosaur in life, but most paleontologists do not believe that the bones and armor came from the same animal.