trilobitet

Trilobites were an extinct group of marine arthropods that lived from the early Cambrian period to the end of the Permian period, approximately 521 to 252 million years ago. They are among the most recognizable fossils from the Paleozoic Era. Their name comes from the three distinct longitudinal lobes of their body: a central axial lobe and two pleural lobes on either side.

The body of a trilobite was divided into three main parts: the head shield, or cephalon; the thorax, composed of articulated segments; and the tail shield, or pygidium. Trilobites possessed a hard exoskeleton made of calcite, which they molted as they grew. Their eyes were typically compound and located on the cephalon.

Trilobites inhabited a wide range of marine environments, from shallow coastal waters to the deep sea. They had diverse lifestyles, with some being free-swimming predators, others scavengers on the seafloor, and some likely burrowing organisms. Their fossil record is extensive, providing valuable insights into ancient marine ecosystems and evolutionary history. The extinction of trilobites occurred during the Permian-Triassic extinction event, the most severe extinction event in Earth's history.