Trilobites : Study
A new study finds that a trilobite species with exceptionally well-preserved fossils from upstate New York has an additional set of legs underneath its head.
- Trilobites are a group of extinct marine arthropods.
- Tri-lob-ite means three-part-body in Latin.
- They first appeared around 521 million years ago, shortly after the beginning of the Cambrian period, living through the majority of the Paleozoic Era for nearly 300 million years.
- They died out at the end of the Permian, 251 million years ago, killed by the end Permian mass extinction event that removed over 90% of all species on Earth.
- They are recognized by their distinctive three-lobed, three-segmented form.
- Trilobites, like other arthropods, had an external skeleton, called exoskeleton, composed of chitinous material.
- Trilobites periodically shed their exoskeleton to accommodate growth. This process is called molting. Most fossil trilobites are actually fossil trilobite molts.
- Trilobites were the first group of animals in the animal kingdom to develop complex eyes.
- They were also one of the first organisms to develop multiple appendages for moving around.
- Some trilobites could swim, others burrowed or crawled around on muddy sea floors.
- The smallest trilobite fossils are a centimeter or less in size. The largest trilobites were more than 70 cm long.
