Yellowstone National Park, Agnostid trilobite

YELL-165705: A small, Agnostid trilobite (YELL-165705) head is shown here. How did these little arthropods survive 500 million years ago? From their lack of eyes and poorly suited swimming body, scientists infer that they were most likely pelagic and floated around the open ocean. This particular Agnostid trilobite is over 500 million years old and was collected from the Wolsey Shale from Mount Holmes in Yellowstone National Park. Scientists use clues from the trilobite’s physical features and the type of rock they were fossilized in, to infer the paleo-environment of the area, which at this time would have been described as a moderate to deep-water environment.;
Megan Norr;
March 2016;
Catalog #20798d;
Original #USNM_165705