1.3" Elrathia Trilobite Molt - Wheeler Shale, Utah
While other organisms enjoyed the good life of sunshine and warmth along equatorial shorelines, Elrathia filled the dark benthic zone on the border of very little oxygen and none at all.
Trilobites, one of the earliest arthropods, first appeared in the Early Cambrian (521 mya) They are relics of the Cambrian Explosion. Elrathia proves that adaptation to such inhospitable environments had developed as early as the Middle Cambrian (509-497 mya). The size and prolific presence of Elrathia kingii is extraordinary for an inhabitant an exaerobic world. There must have been a significant food web- which is an ecological conundrum at this time.
Elrathia kingi lived in a sunless world whose primary producers may have used energy sources that still remain a mystery. Rapid burial and underwater landslides helped to preserve a snapshot of their life on the edge. Trilobites were tough, dominating, and diverse- yet they did not make it beyond the mass extinction at the end of the Permian (250 mya).
The Wheeler Shale, a remnant of an ancient embayment where the ocean intruded into Utah, is perched in the strikingly arid and steep terrain of the House Range. Walcott awarded the areas limestone rocks and clay their title, but long before Walcott, Native Americans in the region regarded the trilobites with respect and appreciation. Today there are several commercial quarries operating in the Wheeler Shale including U-Dig where you can dig your own trilobites.