0.35" Peronopsis Agnostid Trilobite Fossil - Utah

Species: Peronopsis sp.

Age: ~500 million years old (Middle Cambrian)

Formation: Wheeler Shale

Location: House Range, Utah

This is a small but interesting fossil trilobite from the Wheller Shale formation in Utah. It is around 0.35 inches in length, and it is roughly 500 million years old!

Peronopsis is an extinct genus of agnostid trilobite that thrived during the Cambrian Period, roughly 500 million years ago. These tiny marine creatures are easily recognized by their isopygous body plan, meaning their head shield and tail shield are nearly identical in size and shape. Unlike many of their larger relatives, Peronopsis lacked eyes and likely lived on or near the muddy ocean floor in deep-water environments. Because they were so widespread and evolved rapidly, their fossils are frequently used by scientists as index fossils to help determine the age of rock layers.