Description

Haplophrentis carinatus
Hyolithid
Middle Cambrian
Burgess Shale, Stephens Formation
Field, British Columbia, Canada

11mm hyolith on 19mm matrix.

Hyolithids are shelled invertebrates of uncertain classification though the latest research places them perhaps related to brachiopods.  They reached their greatest abundance and diversity during the Cambrian but suffered greatly during the mass extinction at the end of that period.  The group managed to survive into the Permian before becoming extinct.