Thecideida

Thecideida is an order of cryptic articulate brachiopods characterized by their small size and habit of cementing their ventral valves to hard substrates such as shells, rocks and carbonate hardgrounds. Thecideides first appeared in the Triassic^[1] and are common today.^[2][3]

Thecidium mediterraneum, A. natural size: B. section through shell (magnified)

Thecideida Temporal range: Triassic–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Thecideide brachiopod (T), sabellid worm tube (S) and bryozoans (B) on the shell of the bivalve Ctenostreon from the Jurassic of Poland
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Brachiopoda
Class:	Rhynchonellata
Order:	Thecideida Elliott, 1958
Superfamilies
See text.

Taxonomy

Order Thecideida

• Superfamily Thecideoidea Gray, 1840
• Superfamily Thecospiroidea Bittner, 1890