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Arenicolidae

Arenicolidae
Lugworm cast, Red Wharf Bay, Isle of Anglesey - geograph.org.uk - 30354.jpg
Cast and depression caused by buried Arenicola marina.
Scientific classification
Kingdom: Animalia
Phylum: Annelida
Class: Polychaeta
Subclass: Scolecida
Order: Capitellida
Family: Arenicolidae
Johnston, 1835
Genera
See text

Arenicolidae is a family of marine polychaete worms. They are commonly known as lugworms and the little coils of sand they produce are commonly seen on the beach. Arenicolids are found worldwide, mostly living in burrows in sandy substrates. Most are deposit feeders but some graze on algae.

The arenicolids are characterised by an elongated cylindrical body separated into two or three distinct regions. The prostomium has no appendages or palps. There are one or two anterior segments without setae. On the other segments, all the setae are unbranched, including the capillary setae and the rostrate uncini. The notopodia are bluntly truncate and the neuropodia are elongated tori forming long transverse welts in some of the setigers. The notosetae have either a capillary function or act as limbs and the neurosetae are rostrate hooks. There are branchiae present on some of the setigers in the middle or posterior regions. Apart from the genus Branchiomaldane, the lugworms are not easy to confuse with other polychaetes. Their tough cuticle and their distinct branchial region with strongly tufted branchiae are characteristic.


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