Cephalodiscida

Cephalodiscida is one of two orders in the class Pterobranchia, which are small, worm-shaped animals. Members belong to the hemichordates. Species in this order are sessile, living in clear water and secrete tubes on the ocean floor.

Taxonomy
The order is a small one, with only two known families, each containing a single extant genus. The validity of the family Atubaridae, who has only a sole member, is regarded as questionable.


 * Order Cephalodiscida Fowler 1892
 * Family Cephalodiscidae Harmer 1905
 * Genus †Aellograptus Obut 1964
 * Genus †Eocephalodiscus Kozlowski 1938 ex Kozlowski 1949
 * Genus †Melanostrophus Öpik 1930 ex Öpik 1933
 * Genus †Pterobranchites Kozlowski 1967
 * Genus Atubaria Sato 1936
 * Genus Cephalodiscus M'Intosh 1882
 * Family †Rotaciurcidae Briggs and Koch 2023
 * Genus †Rotaciurca Briggs and Koch 2023