ELRATHIA KINGI, 550 MILLION YEARS OLD, UTAH
Elrathia kingi are trilobites from the mid-Cambrian period; 550 million years old. These
trilobites are an extinct form of marine life occurring in the Wheeler shale west of Delta, UT.
Trilobites were an exclusively marine group of arthropods that appeared in the Cambrian Period and persisted throughout the Paleozoic, eventually becoming extinct in the Permian Period. Most were small, bottom-dwelling organisms that fed on organic matter in sediment on the sea bottom. The body is divided in three segments: head (cephalon), middle (thorax), and tail (pygidium). Many species had large, compound eyes.