Glossary H
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HABITAT
A habitat is a space (which includes food, water and shelter) suitable
for the survival and reproduction of an organism.
HADEAN EON
The Hadean Eon lasted from 4.6 to 3.9 billion years ago. This "Rockless
Eon" was the time when the Earth's continental and oceanic crusts
were solidifying. The name Hadean was coined by the geologist Preston
E. Cloud in the 1960s.
HADROCODIUM
Hadrocodium (meaning: "heavy or full head") was a tiny mammalian
ancestor about the size of a paperclip. It is the earliest-known animal
with such mammal-like features. This shrew-like quadruped had a long tail,
a long snout, delicate teeth, three middle ear bones, a powerful jaw hinge,
matching upper and lower teeth, a large brain case, and five-toed feet.
Hadrocodium was an insectivore (insect-eater) that may have been nocturnal
(most active at night). It lived about 195 million years ago. A skull
(half an inch (12 millimeters) long) was found in the Lufeng Basin in
Yunnan, China, in 1985 (it was only recently determined that it was a
new species). The type species is Hadrocodium wui; was named by Zhe-Xi
Luo et al.
HADROSAURIDAE
Hadrosaurids, or duck-billed dinosaurs, were the biggest ornithopods (a
type of ornithischian or bird-hipped dinosaurs). They could walk on two
or four legs. These plant-eaters lived during the late Cretaceous period.
Hadrosaur means 'big or bulky lizard.' Hadrosaurs had a wide, flat, toothless
beak, hundreds of cheek teeth and powerful jaws. Their hind legs were
large and each limb had four digits. Maiasaura, Edmontosaurus, Hadrosaurus,
etc. were hadrosaurs. The hadrosaurs evolved from the iguanodontids.
Hadrosaur
The hadrosaurs, also known as the duck-billed dinosaurs, were a family
of bird-hipped herbivore dinosaurs that appeared in the Late Cretaceous
period. They had long powerful hind limbs with three-toed feet and smaller
more delicate front legs. Many species were characterised by elaborate
head crests.
HAINOSAURUS
Hainosaurus (meaning: "Haine (River) lizard") was a huge mosasaur
that was about 50 feet (15 m) long. The skull is about 1.5 m long. This
is the largest mosasaur yet found. They had sharp teeth and ate fish,
turtles, and other marine organisms. Fossils have been found in Europe.
Hainosaurus was named by Dollo in 1885.
HALLUCIGENIA
Hallucigenia was a strange, spiked animal that lived during the Cambrian
Period, roughly 500 million years ago (found in Canada's Burgess Shale
and in China). Hallucigenia as an onychophoran (a "velvet worm")
that had 7 tentacles on its top side which it used to grasp food; it used
7 pairs of spines on the underside for walking. Forty fossils of Hallucigenia
have been found.
HALLUX
A hallux, or dewclaw, is a functionless claw that doesn't hit the ground.
Some dinosaurs had dewclaws.
HALTICOSAURUS
(pronounced HALL-tik-oh-SAWR-us) Halticosaurus (meaning: "leaping
lizard") was a late Triassic dinosaur from about 222 million years
ago. It was a very early dinosaur and its classification is unsure (it
is perhaps a theropod). It was a speedy bipedal dinosaur about 17 feet
(5 m) long. It had a short neck, very long feet, a long, large head with
many sharp teeth. Its feet suggest that it was a theropod (a meat eater)
but its hip and vertebrae are more like those of plant eaters. An incomplete
skeleton was found in Wuerttemberg, Germany in 1906 and named by paleontologist
von Huene.
HAPLOCANTHOSAURUS
(pronounced hap-lo-KAN-tho-SAWR-us) Haplocanthosaurus (meaning: "single
spine lizard") was a sauropod dinosaur from the late Jurassic Period,
about 156-145 million years ago. This plant-eater had a long neck, a long
tail, a bulky body and a small head. It was about 70 ft (21 m) long. Partial
fossils have been found in Colorado and Wyoming, USA. The type species
is H. priscus. It was found by paleontologist John Bell Hatcher in 1901,
and named by him in 1903.
HARPYMIMUS
(pronounced HAR-pee-MIME-us) Harpymimus ("Harpy [a Greek bird-woman
monster] mimic") was a theropod dinosaur, a bipedal meat-eater that
lived during the Cretaceous Period, about 119- 97.5 million years ago.
It had a beak and 10 - 11 conical teeth in its lower jaw. Its diet is
uncertain. It had tapered, three-fingered hands. This extremely fast-running
dinosaur had thin, long-shinned legs and a light-weight body. It was about
6.5 feet (2 m) long and may have weighed about 275 pounds (125 kg). This
bird-like dinosaur is known from a skull and a few bones found in Mongolia.
Harpymimus was named by Barsbold and Perle in 1984. The type species is
H. okladnikovi.
HAWKINS, BENJAMIN W.
The first dinosaur models were made by Benjamin Waterhouse Hawkins of
England in 1854. He made and sold plaster-cast dinosaurs through the Ward's
catalogue of scientific supplies. His original models included Igauanodon,
Hylaeosaurus, Megalosaurus, Plesiosaurus and Ichthyosurus. The first dinosaur
used for adult amusement was a life-size model of an Iguanodon (made of
concrete by Hawkins) that was used to house a dinner party for scientists
(including Richard Owen, who coined the term dinosaur) at a major exhibition
in London, England, in 1854. The invitations to the party were sent on
fake pterodactyl wings..
HELICOPRION
Helicoprion was an ancient fish from the Late Paleozoic (it appeared during
the Carboniferous period, about 345 million years ago). This predatory
fish is known only from fossilized teeth; it probably had a cartilaginous
body (which does not fossilized well and is possibly why a fossil skeleton
from this fish has not been found). Helicoprion was probably related to
sharks or was a shark itself. It had big, flattened teeth that were probably
used for crushing shellfish and arthropods. These teeth grew in a series
of coiled whorls; new teeth relaced broken and worn-out teeth, but the
old ones went inside the jaw. These fossilized teeth have been found worldwide.
Classification: Family Edestidae
HENDRICKSON, SUE
Sue Hendrickson (December 2, 1949 - ) is a self-taught fossil hunter (specializing
in fossil inclusions in amber), marine archaeologist, adventurer and explorer.
In South Dakota in 1990, Hendrickson found the remarkable Tyrannosaurus
rex fossil that is now known as Sue. This Tyrannosaurus rex fossil is
the largest and most complete Tyrannosaurus rex found to date. Sue (the
fossil) is now displayed at the Field Museum in Chicago, Illinois, USA.
HENODUS
(pronounced hen-o-dus) Henodus was a marine reptile about 3.25 feet (1
m) long. It was not a dinosaur, but a placodont. It had no teeth, but
used its hard, horny beak to get and crush shellfish. It had a box-like
head, 4 legs, a short, pointed tail, and a flat body. It was protected
from predators, like Ichthyosaurs, by bony plates that formed a shell
on its back and stomach. Although it resembled a turtle, it was not closely
related to turtles. It lived during the late Triassic Period, when it
swam in the Tethys Sea. Fossils have been found in Germany. Classification:
Order Placondontia, Family Henodontidae (armored placodonts).
Herbivore
An animal that feeds only on plants, and is specially adapted to be able
to extract nutrition from tough foliage.
Herrerasaurus
Herrerasaurus was a late Triassic archosaur from about 230 million years
ago. It was a speedy bipedal carnivore, 5 m long and weighing about 300
kg, with a short neck and large head. This was one of the first flesh-eating
dinosaurs and is known from several skeletons found in Argentina.
HESPERORNIS
(pronounced HES-per-OR-nis) Hesperornis (meaning: "western bird")
was an early, flightless bird that lived during the late Cretaceous Period.
This diving bird was about 3 feet (1 m) long and had webbed feet, a long,
toothed beak, and strong legs. Although it couldn't fly, it was probably
a strong swimmer and likely lived near coastlines and ate fish. Fossils
have been found in North America. Hesperornis was named by paleontologist
O. Marsh in 1872 from fossils found near the Smoky Hill River in Kansas,
USA.
HESPEROSAURUS
(pronounced hes-PARE-uh-SAWR-us) Hesperosaurus (meaning: "western
lizard," and originally called Hesperisaurus) was a primitive stegosaurid
dinosaur that had a single row of rounded plates running down its back;
it also had four bony spikes (thagomizers) at the end of the tail. This
plant-eating dinosaur lived during the late Jurassic Period, roughly 150
million years ago. Fossils have been found in the Morrison Formation,
Jackson County, Wyoming, USA, North America. The type species is Hesperisaurus
mjosi; it was named by paleontologists K. Carpenter et al. in 2001.
HETEROCHRONY
(pronounced HET-er-oh-CROW-knee) heterochrony (meaning: "differeny
time") is a evolutionary (genetically determined) change in the timing
of developmental events or a change in the growth rate, as compared to
the same events in ancestors. For example, the time it takes to grow to
adulthood may change over time.
HETERODONTOSAURUS
(pronounced HET-er-oh-DON-toh-SAWR-us) Heterodontosaurus (meaning: "different-tooth
lizard") was an early ornithischian dinosaur. It was an herbivore
with three different types of teeth. This lightly-built plant-eater was
up to 4 ft (1.2 m) long and weighed perhaps 10 kg. It lived during the
early Jurassic Period, about 208-200 million years ago. The type species
is H. tucki. Heterodontosaurus was named by Crompton and Charis in 1962.
HETEROTROPH
(pronounced HET-er-oh-TROFE) A heterotroph (or consumer) is a living thing
that eats other living things to survive. It cannot make its own food
(unlike plants, which are autotrophs). Animals are heterotrophs.