Trilobites
They are vanished, hard-shelled animals that lived in
the seas millions of years ago. They evolved at the
beginning of the Paleozoic Era (over 500 million years
ago) and went extinct during the late Permian stage
(about 248 million years ago). The Cambrian era is known
as "The Age of Trilobites."
Trilobites were very
ordinary and very varied; over 15,000 species of
trilobites are known. Some trilobites crawled along the
sea floor, some swam, and others drifted with ocean
currents.
The different trilobite
species probably had diverse diets; some were herbivores
(eating vegetation), some were detrivores (eating
decomposed material) and some were scavengers (eating
carrion).
Body:
Trilobites were
sea invertebrates that
had hard, three-lobed shells (the axial lobe and two
pleural lobes), hence the name "trilobite". The body is
alienated into three parts, the cephalon (head), the
segmented thorax, and the pygidium (tail piece).
These arthropods had jointed legs, complex eyes, and
antennae. They ranged in size from less than 1/4 inch
(0.6 cm) to over 2 feet (0.6 m) long.
Protection:
Many
trilobites had defensive spines. Some could turn up into
a ball, and some could burrow into the sea floor.
