Craniidae

Craniidae Temporal range: Ordovician–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Petrocrania scabiosa encrusting the edge of a strophomenide brachiopod; Upper Ordovician of northern Kentucky.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Brachiopoda
Class:	Craniata
Order:	Craniida Waagen, 1885
Suborder:	Craniidina Waagen, 1885
Superfamily:	Cranioidea Menke, 1828
Family:	Craniidae Menke, 1828
Genera
See text.
Synonyms
Valdiviathyrididae

The Craniidae are a family of brachiopods, the only surviving members of the subphylum Craniiformea. They are the only members of the order Craniida, the monotypic suborder Craniidina, and the superfamily Cranioidea; consequently, the latter two taxa are at present redundant and rarely used.There are three living genera within Craniidae: Neoancistrocrania, Novocrania, and Valdiviathyris.^[1] As adults, craniids either live freely on the ocean floor or, more commonly, cement themselves onto a hard object with all or part of the ventral valve.

Like the burrowing lingulids, Craniids are inarticulate brachiopods. There are no outgrowths forming a hinge between both valves, nor is there any support for the lophophore. Unlike lingulids, which have shells consisting of apatite and organic material, craniids have shells composed mainly of calcium carbonate. No craniids are known to bear a pedicle at any development stage.^[2][3]