Trilobites are an extinct group of marine arthropods that lived during the Paleozoic Era, known for their distinctive three-lobed, three-segmented body plan. They are significant in paleontology for understanding the evolution of early life, the diversity of ancient marine ecosystems, and the use of fossils in biostratigraphy.
Source Fortey, R. A. (2000). “Trilobite! Eyewitness to Evolution.” Vintage Books.