Glossary RAD - RIC
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RADIOISOTOPE DATING
Radioisotope dating of igneous rock layers is used to find out how old
the rock is (when the igneous rock formed). One way of dating fossils
is by dating bracketing layers of igneous rock.
RAHONAVIS
(pronounced rah-hoo-NAY-vis) Rahonavis (meaning: "Cloud-menace bird")
was a primitive bird/dinosaur with sickle-like claws on its feet. It was
half-way between a dromaeosaurid dinosaur and a bird. It lived during
the late Cretaceous Period. This carnivore was about the size of a raven.
Fossils have been found in Madagascar. The type species is R. ostromi.
Rahonavis was named by Forster, Sampson, Chiappe, and Krause in 1998.
RAJASAURUS
(pronounced rah-hoo-NAY-vis) Rajasaurus narmadensis (meaning "regal
dinosaur from the Narmada") was a heavy-boned meat-eating dinosaur
(an abelisaur) that lived during the late Cretaceous Period. This carnivore
was about 9 meters long. Fossils have been found in the Narmada River
region of India. The type species is R. narmadensis. Rahonavis was named
by Wilson, Sereno, Srivastava, Bhatt, Khosla and Sahni in 2003; the fossils
were found in 1983 by Suresh Srivastava and Ashok Sahni.
RAMAPITHECUS
Ramapithecus (meaning: "Rama's ape") was an arboreal (tree-living)
primate that was probably an ancestor of modern-day orangutans. This extinct
ape lived roughly 14 to 8 million years ago, during the Miocene epoch.
The first fossils were found in 1932 by Edward G. Lewis. Fossils have
been discovered in northern India, Pakistan, and eastern Africa. Until
a very primitive, complete jaw was found in 1976, Ramapithecus was thought
to have been an ancestor of man.
RANCHO LA BREA TAR PITS
The Rancho La Brea Tar Pits are a series of over 100 asphalt pits located
in southern California, USA ("brea" means "tar" in
Spanish). These tar pits contain many animal bones, including Ice Age
fossils. Over 650 species of Pleistocene Epoch plants and animals have
been found and identified at La Brea (dating from about 10,000 to 40,000
years ago), including many mammoths, mastodons, saber-toothed cats (including
Smilodon fatalis), dire wolves (Canis dirus), giant sloths (Glossotherium
harlani), ground sloths, bison, a western horse, the short-faced bear
(Arctodus simus), rodents, rabbits, birds, turtles, lizards, insects,
mollusks, and many other animals and plants. One ancient human skeleton
was found in the La Brea pits (about 17 bones from a woman who dates from
about 9,000 years ago). Tar pits are pools of gooey asphalt that are created
when crude oil seeps up from deep inside the Earth through a crack (called
a fissure). The less dense elements of the crude oil evaporate, leaving
a deep, conical deposit of asphalt (a very sticky mess). Water pools on
the tar, attracting thirsty animals. As animals get stuck in the tar,
predators are attracted to the trapped animal, and then they get stuck
in the asphalt too. The animals' bones, teeth, and other hard parts are
well-preserved in this environment (but they turn brown from the asphalt).
RAPATOR
(pronounced ruh-PAY-tor) Rapator (meaning: "plunderer") was
a theropod dinosaur that lived during the early Cretaceous Period, from
113 -97.5 million years ago. This bipedal carnivore was very roughly 30
ft (9 m) long. Fossils have been found in Australia. The type species
is R. ornitholestoides. Rapator was named by von Huene in 1932. This is
a doubtful genus since so little fossils material was found (just a toe
bone); it may be the same as Walgettosuchus.
RAPETOSAURUS
Rapetosaurus (meaning: "mischievous giant lizard") was a sauropod
long-necked, plant-eating dinosaur that lived during the late Cretaceous
Period, about 70-65 million years ago. This quadruped was roughly 50 ft
(15 m) long. Fossils have been found in Madagascar, off the southeastern
coast of Africa. The type species is R. krausei. Rapetosaurus was named
by Rogers and Forster, 2001.
RAUISUCHIAN
Rauisuchians (meaning: "Rau's crocodiles") were large-skulled
archosaurs (not dinosaurs) from the mid to late Triassic Period. These
meat-eating reptiles had powerful jaws and were the top predators of their
time, but went extinct at the end of the Triassic. They are frequently
described as animals "trying to become dinosaurs." They were
generally from 7 to 15 ft (2 to 5 m) long, but a few were larger. Rauisuchians
were mostly quadrupedal, but some may have been bipedal. Some had armored
plates. Fossils have been found in North and South America, Europe, India,
China and Africa. Some Rauisuchians include Saurosuchus (the biggest),
Ticinosuchus, Dongusuchus, Energosuchus, Fasolasuchus, Mandasuchus, and
many others.
RAYOSOSAURUS
(pronounced rie-YOH-so-SAWR-us) Rayososaurus (meaning: "Rayoso [A
Formation in Argentina] lizard") was a large, diplodocid sauropod
dinosaur from the early Cretaceous Period, about 99 million years ago.
This quadrupedal plant-eater had a whip-like tail, a long neck, a small
head, clawed hind legs, a high-arched back, and a bulky body. Fossils
have been found in Argentina. The type species is R. agrionensis. Rayososaurus
was named by Bonaparte in 1995. This is a doubtful genus
REBBACHISAURUS
(pronounced re-BASH-eh-SAWR-us ) Rebbachisaurus (meaning: "Rebbach-territory
{in Morocco} lizard") was a large, diplodocid sauropod dinosaur from
the early Cretaceous Period, about 113 to 97.5 million years ago. This
quadrupedal plant-eater had a whip-like tail, a long neck, a small head,
clawed hind legs, a high-arched back, and a bulky body. It may have had
a sail on its back. Rebbachisaurus was about 68 ft (20 m) long. Fossils
have been found in Morocco and Niger, Africa. The type species is R. garasbae.
Rebbachisaurus was named by Lavocat in 1954.
REGRESSION
Regression is the exposure of continental land as the sea level decreases,
usually caused by increasing polar ice and glacier formation. Another
causes is the local uplift of the continental land.
RELATIVE AGE DATING
Relative age dating seeks to determine the order in which events occurred.
Compare with absolute age dating.
Reptile
A group of air breathing, scaly-bodied animals with back bones that evolved
from the amphibians. They fertilise their eggs internally and are not
reliant on water to lay their eggs in. Modern turtles, crocodiles, lizards
and snakes are all reptiles.
REVUELTOSAURUS
(pronounced re-VWELL-to-SAWR-us) Revueltosaurus (meaning: "Revuelto
]Creek] lizard") is a poorly-known ornithischian dinosaur that lived
during the late Triassic Period, about 220 million years ago. Only fossil
teeth of this bipedal plant-eater have been found in New Mexico and Arizona,
USA. The type species is R. callenderi . Revueltosaurus was named by K.
Padian in 1990; it was named for the Revuelto Creek in New Mexico, USA.
This is a duious genus of dinosuar due to the sparsity of fossils.
RHABDODON
(pronounced RAB-doe-don) Rhabdodon (meaning: "rod or fluted tooth")
was a small, iguanodontid ornithopod dinosaur from the early Cretaceous
Period, about 83 to 65 million years ago. This bipedal plant-eater had
a long tail, a short neck, a beaked head, and a bulky body. Rhabdodon
was about 14.5 ft (4 m) long. Fossils have been found in Austria, France,
Hungary, and Romania. The type species is R. priscus. Rhabdodon was named
by Matheron in 1869.
Rhamphorhynchus
This medium sized, carnivorous pterosaur lived in the Late Jurassic period.
It lived in large marine colonies and fed almost entirely on fish by skimming
the water with its beak. It had a wing span of up to approximately 1.75
metres.
RHOETOSAURUS
(pronounced REET-oh-SAWR-us) Rhoetosaurus (meaning: "Rhoetos' (mythological
Greek giant) lizard") was a sauropod dinosaur from the middle Jurassic
Period, about 181 to 175 million years ago. This quadrupedal plant-eater
had a long tail, a long neck, a small, box-like head, and a bulky body.
Rhoetosaurus was about 40 ft (12 m) long. Fossils have been found in Queensland,
Australia. The type species is R. brownei. Rhoetosaurus was named by Longman
in 1925.
RHYNCHOSAURS
Rhynchosaurs (meaning: "beaked lizard") were common quadrupedal,
herbivore, land-dwelling, archosauriform reptiles from the late Triassic
Period. These short, pig-like reptiles had tusks and beaks and were about
3.3 to 6.5 ft (1-2 m) long. Scaphonyx was a rhynchosaur.
RICARDOESTESIA
(pronounced ri-KARD-o-es-TEE-zee-ah) Ricardoestesia (named for Richard
Estes) was a small coelurosaurid dinosaur from the late Cretaceous Period,
about 83 to 70 million years ago. This bipedal carnivore was about 6.5
ft (2 m) long and had a long, thin lower jaw. Fossils (mostly teeth and
jaw) have been found in Alberta, Saskatchewan, Montana, and Wyoming. The
type species is R. gilmorei. Rahonavis was named by Currie, Rigby, and
Sloan in 1990.