Discinida is an order of

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of 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 e ...

s comprising the extant superfamily

Discinoidea Discinoidea is a superfamily of Discinid brachiopods. For discussion of Discinid taxonomy, see Discinidae. The history of the superfamily Discinoidea spans almost the entire Phanerozoic Eon, and has been described as ″one of the few ′living ...

, and the extinct superfamilies Botsfordioidea (early—mid-Cambrian) and Acrotheloidea (early Cambrian–Early Ordovician). It represents a sister taxon to the Lingulids, and is possibly

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

with respect to the Acrotretoids.—or the acrotretids are paraphyletic with respect to it.> The group displays a broad range of shell structures, some of which incorporate substantial organic or silicified components.

References

Brachiopod orders Extant Cambrian first appearances {{brachiopod-stub