Wikipedia
Bristoliinae
The Bristoliinae is an extinct subfamily of trilobites, fossil marine arthropods, with species of small to average size. Species of belonging to this subfamily lived during the Botomian and Toyonian stage (Olenellus-zone), 522-513 million years ago, in the former continent of Laurentia, including what are today Mexico, the Appalachian Mountains and the South-Western United States, and Canada (North-West Territories).