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Hesionidae

Hesionidae
Oxydromus pugettensis.jpg
Oxydromus pugettensis
Scientific classification
Kingdom: Animalia
Phylum: Annelida
Class: Polychaeta
Order: Aciculata
Suborder: Phyllodocida
Family: Hesionidae
Grube, 1850
Subfamilies

Hesioninae
Microphthalminae
Ophiodrominae
and see text


Hesioninae
Microphthalminae
Ophiodrominae
and see text

Hesionidae are a family of phyllodocid "bristle worms" (class Polychaeta). They are (like almost all polychaetes) marine organisms. Most are found on the continental shelf; Hesiocaeca methanicola is found on methane ice, where it feeds on bacterial biofilms.

A characteristic apomorphy of the Hesionidae are the cirrophores of the anterior segments, which are well-developed cup-like sheaths; the cirri of the subsequent segments insert into the parapodia directly, or with just a vestigial cirrophore.

As phyllodocids, the Hesionidae belong to the order Aciculata, one of the three main clades of polychaetes. They appear to be part of the basal radiation of the main lineage of phyllodocids, alongside such families as the ragworms (Nereididae), the Pilargidae and Sphaerodoridae which are closely related to each other, the very ancient Syllidae, and perhaps the more advanced catworms (Nephtyidae). 


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