Large, 3.35" Isoteloides - Fillmore Formation, Utah

Large, Isoteloides - Fillmore Formation, Utah #108189

This is a large, 3.35" Isoteloides trilobite from the Carolinites nevadensis Zone in the Fillmore Formation in Utah. It appears very similar to Isoteloides flexus found significantly higher in the formation, but every species in this zone has been described as different species from the higher zones, so I suspect this one would be also.

Despite missing it's left cheek it's the most complete, large specimen we've recovered since we started digging the layers in the Carolinites nevadensis Zone. There is some crack-fill, shell restoration, mostly on the tail of the trilobite, <5% in total.

About Trilobites

Trilobites are an extinct class of marine arthropods that thrived for nearly 270 million years, from the early Cambrian to the end of the Permian period (around 521 to 252 million years ago). They are one of the most successful and diverse groups in the history of life, with over 25,000 described species spanning a wide range of sizes, shapes, and ecological niches. Known for their distinctive, segmented exoskeletons, trilobites provide invaluable insights into the evolutionary history of arthropods and the dynamics of ancient marine ecosystems.