Glossary CRA - CRY
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CRATEROSAURUS
(pronounced KRAY-ter-oh-SAWR-us) Craterosaurus (meaning: "crater
or cup lizard") was a stegosaurid dinosaur. This plated, quadrupedal
plant-eater was about 13 ft (4 m) long and weighed roughly 560 kg. It
lived during the early Cretaceous Period, 138-135 million years ago. A
single, incomplete vertebra was found in England. Unlike other stegosaurid
vertebrae, it has pitting on its top surface (this bone was originally
thought to be the braincase, hence its name). The type species is C. pottonensis.
Craterosaurus was named by paleontologist Seeley in 1874.
Crayfish
The common name for a number of lobster-like, freshwater crustaceans.
CREODONT
Creodonts were an order of meat-eating mammals that were very common roughly
60 to 30 million years ago; they were the dominant carnivorous mammals
during the Tertiary period. They lived in Asia, Europe, Africa, and North
America, going extinct 7 million years ago, during the late Miocene. Creodonts
were quadrupeds with clawed feet, a small brain, large jaws and many sharp
teeth. Some creodonts included the mongoose-like Prototomus, the bear-like
Sarkastodon (Family Oxyaenidae), the wolf-like Hyaenodon (Family Hyaenodontidae),
Pterodon, Andrewsarchus (Family Mesonychidae) and Megistotherium. Creodonts
were first described by paleontologist Edward Drinker Cope in 1877.
CREST
A crest is a growth on an animal's head. Many dinosaurs, like Corythosaurus
and Lambeosaurus, had bony crests on their heads.
Cretaceous Period
The Early Cretaceous period lasted from 144 million years ago to 97 million
years ago. The Late Cretaceous period lasted from 97 to 65 million years
ago.
CRETODUS
Cretodus is an extinct genus of Mackerel sharks that lived during the
late Cretaceous period. This shark is known only from fossilized teeth
and vertebrae that have been found in Africa, Europe, and North America.
The length of the teeth (from the tip of the crown to the tip of the root)
is about 2 inches (5 cm). Cretodus was named by Sokolov in 1965. Classification:
Order Lamniformes, Family Cretoxyrhinidae.
Crocodile
The only surviving archosaurs, crocodiles are cold-blooded, egg-laying
reptiles. They have changed very little in their history, nearly all being
aquatic or semi-aquatic hunters and scavengers.
CRO-MAGNON
Cro-Magnon man was an early group of Homo sapiens (the species to which
we belong) that lived about 40,000 years ago in what is now Europe. Skeletal
remains of the Cro-Magnon were first found in caverns in Les Eyzies, Dordogne,
France (in 1868).
CROSSOPTERYGII
Crossopterygii (lobe-finned fish) are bony fish whose fins are supported
on fleshy lobes. Lobe-finned fish appeared during the Silurian period
(roughly 420 million years ago). The Coelacanth and the extinct Rhipidistians
are examples of lobe-finned fish.
Crustacean
A class of arthropods that includes crabs, lobsters, wood-lice, barnacles
and waterfleas. They evolved in the Cambrian period, or maybe even earlier,
and became diverse and numerous in the Mesozoic era.
Cryolophosaurus
Cryolophosaurus, meaning . frozen crested reptile. , was a bipedal, meat-eating
dinosaur, about 6 metres long. It had a horn-like, upward pointing crest
above its eyes. It lived in what is now Antarctica during the early Jurassic
period, roughly 190 million years ago. It is the only theropod known from
the Antarctic, and the first Antarctic dinosaur ever described.
Cryptoclidus
This large, four flippered plesiosaur was a carnivore living in the Late
Jurassic period. It glided through the open seas in search of fish or
squid. It is thought that Cryptoclidus swallowed stones, called gastroliths,
to weigh itself down while hunting for prey on the sea bed. It was up
to 8 metres long and could weigh up to 8 tonnes.
CRYPTOZOIC
The Cryptozoic (also called the Proterozoic) was an eon in geological
time that lasted from 2.5 billion years ago to 540 million years ago.
During the Proterozoic/Cryptozoic Eon, the first multicellular life evolved,
including colonial algae, solf-bodied invertebrates, and sponges.
Crinoid
Crinoids are echinoderms, a group of animals that also includes the sea-urchins
and starfish. Most fossil crinoids have a head bearing a crown of arms
(usually five) and lived attached to the sea floor by a stalk. Their superficial
flower-like appearance led to their popular name . sea lilies. . In the
Palaeozoic era crinoids were abundant but they started to decline during
the Mesozoic era. Today there are only a few, mostly free-swimming, forms.
CRYPTOZOOLOGY
Cryptozoology is the study of evidence concerning creatures whose existence
is uncertain, like the Loch Ness monster or the Abominable Snowman.
CRYSTALS
Crystals are solids whose atoms form a very regular pattern.