Yellowstone National Park, Ptychopariid trilobite

YELL-92020: This head of a roughly 520 million year old Ptychopariid trilobite (YELL-92020) is one among many identified from the Pilgrim Limestone, on Mt. Holmes in Yellowstone National Park. Trilobite order Ptychopariid, was abundant during the early Cambrian and became extinct at the end of the Ordovician (~444 million years ago). But, at the end of the Permian all trilobites vanished, along with over 95% of all marine life.;
Megan Norr;
March 2016;
Catalog #20801d;
Original #YELL_92020