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Fossils & Minerals: Arthropods: Trilobites
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Kingdom: Animalia
Phylum: Arthtropoda Class: Trilobita The term trilobite refers to an extinct class of arthropods. Tri-lobe-ite alludes to the three-part, longitudinal division of their exoskeleton. These animals first appeared at the beginning of the Cambrian Period approximately 570 million years ago. They flourished throughout the early Paleozoic Era and then decreased in diversity until their extinction in the late Permian Period about 240 million years ago. These marine invertebrates were primarily bottom dwellers. Fossilized remains of trilobites have been found on every continent. Vision
Exoskeleton In addition to the chitinous exoskeleton typical of all arthropods, trilobites typically possessed a mineralized body covering divided into a cephalon (head), segmented thorax (body) and pygidium (tail). The mineralized dorsal exoskeleton and ventral hypostome probably consisted of a primary layer of calcite with additional thin lamellae of chitin and perhaps apatite. This provided protection for the soft parts of the body. Trilobite exoskeletons may be found intact or, more frequently, as disarticulated parts.. Molting & Enrollment
Varied Shapes
Value Trilobites have been admired by man and have been considered as objects of value for thousands of years. They have been found in archaeological context both in Europe and North America. La Grotte du Trilobite, a 15,000 year old site in France, produced a drilled trilobite which originated more than 2000 kilometers away. In Dudley, England, the "Dudley locust," an Ordovician trilobite of the genus Calymene, has been collected and sold in shops since the 17th century. Today trilobites are prized by collectors and museums throughout the world as objects of beauty and curiosity. Scientists use trilobites as stratigraphic index fossils which help to determine the age of rock formations. The true value of trilobites, however, lies in the story which the fossils tell about the history of life on this planet. This page's information is also available in a pamphlet or poster format. |
Vertebrates Invertebrates - Minerals |
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