Unidentified Trilobite - Elrathia meraspid?

Middle Cambrian,
Wheeler Shale, Utah.

This was found in a small block of matrix bought at a museum, that had just one Elrathia kingii trilobite showing. The Elrathia popped off the matrix, so I dissected the block and found about 15 others, including some Bolaspidella and a few Peronopsis.

This one looks a bit different, though.
This guy is tiny, the coin next to the matrix is a United States dime.