Trilobite

A Trilobite is a marine arthropod that existed during the Paleozoic era.

• Context:
  • It can (typically) be known for its three-lobed, mineralized exoskeleton and significant contribution to our understanding of early marine life.
  • It can (typically) be found in fossil records from the Cambrian to the Permian periods.
  • It can (often) exhibit diverse forms and sizes, ranging from a few millimeters to over 70 centimeters in length.
  • It can range from being a predator to a filter feeder, adapting to various ecological niches in ancient oceans.
  • It can possess a well-defined, three-lobed body plan, distinguishing it from other marine arthropods.
  • It can contribute to fields such as biostratigraphy, paleontology, and evolutionary biology through its extensive fossil record.
  • It can exhibit a symbiotic relationship with sulfur-eating bacteria, especially within the family Olenidae.
  • It can be related to the clade Artiopoda, although the exact relationships within this clade remain uncertain.
  • ...
• Example(s):
  • an Isotelus, which showcases one of the largest trilobites ever found.
  • a Phacops, demonstrating the development of complex, compound eyes in trilobites.
  • a Walliserops, known for its distinctive trident-like anterior appendage.
  • ...
• Counter-Example(s):
  • Crustaceans, which, although also marine arthropods, do not share the trilobite's three-lobed body plan.
  • Eurypterids, another group of extinct marine arthropods, often larger and morphologically different from trilobites.
• See: Symbiosis, Cambrian, Permian, Walliserops, Phacops, Cambropallas, Isotelus, Kolihapeltis, Ceratarges, Seeing Organism.

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References

2024

• (Wikipedia, 2024) ⇒ https://en.wikipedia.org/wiki/Trilobite Retrieved:2024-5-19.
  • Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period () and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last trilobites disappeared in the mass extinction at the end of the Permian about 251.9 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described. By the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton, they left an extensive fossil record. The study of their fossils has facilitated important contributions to biostratigraphy, paleontology, evolutionary biology, and plate tectonics. Trilobites are placed within the clade Artiopoda, which includes many organisms that are morphologically similar to trilobites, but are largely unmineralised. The relationship of Artiopoda to other arthropods is uncertain. Trilobites evolved into many ecological niches; some moved over the seabed as predators, scavengers, or filter feeders, and some swam, feeding on plankton. Some even crawled onto land. Most lifestyles expected of modern marine arthropods are seen in trilobites, with the possible exception of parasitism (where scientific debate continues). Some trilobites (particularly the family Olenidae) are even thought to have evolved a symbiotic relationship with sulfur-eating bacteria from which they derived food. The largest trilobites were more than long and may have weighed as much as .

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