The Mesonacinae comprise an extinct subfamily of trilobites that lived during the Botomian, found in North-America, Greenland and North-Western Scotland. The two genera in this subfamily are Mesonacis and Mesolenellus. References External links Photo of M. vermontanus Trilobite info Olenellidae Cambrian trilobites Cambrian Series 2 first appearances Cambrian Series 2 extinctions Arthropod subfamilies