Isotelus

Isotelus (Greek for 'equal extremities') is an extinct genus of large asaphid trilobites from the Middle and Late Ordovician Period, fairly common in the northeastern United States, northwest Manitoba, southwestern Quebec and southeastern Ontario. Isotelus is the state fossil of Ohio, and through multiple specimens from the 1800s into the modern day has held the title of largest trilobite fossil in the world, reaching over 70 centimetres (28 in) long. Isotelus was carnivorous and a burrower which lived in warm shallow seas, feeding on worms and other soft-bodied animals on and below the substrate. As larvae, Isotelus was planktonic, drifting in the water column with a morphology very different from the adult. Their distinctive morphology with a large shovel-like head, prominent eyes, long genal spines, and their enormous size, makes Isotelus one of the most sought after trilobites in North America.