Hyolithida

The Hyolithida are lophophorates, one of the two orders of hyolithid, the other being the Orthothecida. Most of our knowledge of the hyolithids comes from studies on the Hyolithida.^[2] Both orders had an operculum that was not hinged to the conch. However, the Hyolithida are distinct from the Orthothecida in having additional paired, curved, tusk-like appendages. The Hyolithida were probably bottom feeders living in shallow water, and had tentacules.^[2]

Hyolithida Temporal range: Early Cambrian – Upper Permian[1] PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Class:	†Hyolitha
Order:	†Hyolithida Sussoiev, 1957
Families
See text