Flabelligeridae is a family of polychaete worms, known as bristle-cage worms, notable for their cephalic cage: long slender

chaeta A chaeta or cheta (; ) is a chitinous bristle or seta found on annelid worms, although the term is also frequently used to describe similar structures in other invertebrates such as arthropods. Polychaete annelids (''polychaeta'' literally me ...

e forming a fan-like arrangement surrounding the eversible (able to be turned inside-out) head. Unlike many polychaetes, they also have large, pigmented, complex eyes.

Habitat

These worms live under stones and are known to burrow into sand. They have a cosmopolitan distribution and live in a variety of marine habitats, from the

deep sea The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combination of low tempe ...

to shallow coastal regions.

Subdivisions

The first species was '' Amphridite plumosa'', described from Norway. Flabelligerids were placed in various similar polychaete families until Saint-Joseph erected the family (under the name Flabelligeriens) in 1894. '' Mazopherusa'' is a possible fossil example from the Carboniferous; other fossil material is only dubiously assigned to the family. The Cambrian ''

Iotuba ''Iotuba chengjiangensis'' (sometimes mis-spelt ''Lotuba'') is a 515 million year old Cambrian worm known from the Chengjiang biota. Originally interpreted as a phoronid, the organism is now recognized as an annelid cage worm affiliated with the ...

'' also may belong to the family, however it also appears similar to Acrocirridae.

References

{{Authority control Terebellida Annelid families