Homotelus bromidensis scale in cms CLASS - Trilobita ORDER - Ptychopariida FAMILY - Asaphidae GENUS/SPECIES - Homotelus bromidensis ROCK UNIT - Bromide Formation AGE - Middle Ordovician (465 million years old) LOCALITY - Criner Hills, Oklahoma, USA Large slabs covered with these trilobites have been interpreted as social gatherings, probably for mating. Bees and ants (much more distant arthropod relatives) show highly organized social behavior. It is possible that trilobite did as well. PRI 41459