Spionida is an

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

of marine polychaete worms in the infraclass Canalipalpata. Spionids are cosmopolitan and live in soft substrates in the littoral or neritic zones.Annelid Resources
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Characteristics

Spionids have a single pair of flexible feeding tentacles with grooves, arising directly from the prostomium. The mouth has no jaws and the pharynx is partly eversible. Some species have small eye spots and some a central sensory lobe. Some of the anterior segments paired gills. The parapodia or lateral lobes have large lamellae. The chaetae are unbranched capillaries, spines and hooks.

Families

According to the World Register of Marine Species (WoRMS), the Spionida comprises six families in a single suborder: *Order Spionida **Suborder Spioniformia ***

Apistobranchidae Apistobranchidae is a family of polychaetes belonging to the order Spionida Spionida is an order of marine polychaete worms in the infraclass Canalipalpata. Spionids are cosmopolitan and live in soft substrates in the littoral or neritic zone ...

Mesnil and Caullery, 1898 ***

Longosomatidae Longosomatidae is a family of polychaetes belonging to the order Spionida Spionida is an order of marine polychaete worms in the infraclass Canalipalpata. Spionids are cosmopolitan and live in soft substrates in the littoral or neritic zones. ...

Hartman, 1944 ***

Magelonidae Magelonidae is a family of annelids belonging to the order Spionida. Genera: * '' Dannychaeta'' Chen, Parry, Vinther, Zhai, Hou & Ma, 2020 * ''Magelona ''Magelona'' is a genus of annelids belonging to the family Magelonidae. The genus has cosm ...

Cunningham and Ramage 1888 ***

Poecilochaetidae Poecilochaetidae is a family of marine worms within the Polychaeta. It is a monotypic family containing the single genus '' Poecilochaetus''. Members of this family are benthic The benthic zone is the ecological region at the lowest level of a ...

Hannerz, 1956 ***

Spionidae Spionidae is a family of marine worms within the Polychaeta. Spionids are selective deposit feeders that use their two grooved palps Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group ...

Grube, 1850 *** Trochochaetidae Pettibone, 1963 *** Uncispionidae Green, 1982 Other families such as

Aberrantidae Aberrantidae is a family of annelids belonging to the order Spionida. Genera: * ''Aberranta ''Aberranta'' is a genus of polychaete Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or po ...

and

are sometimes included in Spionida.

References

{{Taxonbar, from=Q3615298 Canalipalpata Protostome orders