Apr 2, 2013
Hyoliths (Class Hyolitha)
Hyoliths were a group of of shelled animals that lived during the Lower Cambrian and Upper Permian era. Their Phylogenetic position is not yet confirmed as it is unclear what they were most closely related to, some say the were molluscs and others say they constitute their own phylum. Most hyoliths had a large calcareous shell, an operculum and two support structures which were called helens. Hyoliths were probably bottom-dwellers like modern gastropods.
Phylogeny
Animalia-Mollusca?-Hyolitha
Image Source(s)