Trigonocercella
Trigonocercella is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the early part of the Arenig stage of the Ordovician Period, a faunal stage which lasted from approximately 478 to 471 million years ago. References Asaphida genera Asaphidae Ordovician trilobites Ordovician trilobites of North America