Thecideida is an order of cryptic articulate

brachiopod Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, w ...

s characterized by their small size and habit of cementing their ventral valves to hard substrates such as shells, rocks and carbonate hardgrounds. Thecideides first appear in the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

(Jaecks and Carlson, 2001) and are common today (Lüter, 2005; Lüter ''et al.'', 2007). Thecidium mediterraneum 001

Taxonomy

Order Thecideida *Superfamily Thecideoidea Gray, 1840 *Superfamily Thecospiroidea Bittner, 1890

References

Paleobiology Database on thecideides
* * * Brachiopod orders Rhynchonellata {{Brachiopod-stub