Family ACOETIDAE

Polyodontes vanderloosi

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Family ACOETIDAE

Compiler and date details

Jan 2011 - P. Hutchings & M. Yerman, Australian Museum, Sydney, New South Wales, Australia

10 July 2003

Introduction

Acoetids are long scale worms that live in thick pliable tubes made from strands of chaetae generated by the worm. Sediment particles may also be incorporated in the tube. Anecdotal reports indicate that these jawed scale-worms may be either predators, scavengers or omnivores. Acoetids are apparently long-lived; their tubes may be associated with similarly long-lived sessile invertebrates and may harbour various commensal organisms. They are widely distributed from low intertidal to depths up to 1500 m, but are not common in benthic samples.

This family was previously known as Polyodontidae, but that name is correctly applied to a family of fishes. Pettibone, 1989 resolved the conflict by resurrecting the generic name Acoetes, thereby making the family name Acoetidae available for this taxon. (Previously Polyodontes was the type genus for the family.)

Figures of 3 genera and 3 species were given by Beesley et al. (2000:App. 1) for representation of the family in Australian waters, and 8 genera and 46 species worldwide.

See Hutchings (2000) for detailed treatment of the family.

Database Notes

proof read against Day & Hutchings 1979 by RW, and DELTA CD 2003 by RTJ

Diagnosis

General features. Body shape vermiform; dorsoventrally flattened; segments numerous (more than about 15); regionation absent. Epidermis more-or-less smooth. Pygidium simple ring or cone. Pygidial appendages present; one pair of cirri.
Head & head structures. Head discrete and compact, dorsal to mouth. Prostomium rounded to oval (anteriorly truncate); anteriorly incised. Facial tubercle present. Eyes present; two pairs; situated on prostomium (usually atop ommatophores); compound with lenses. Prostomial antennae present; include paired anterolateral ones and single medial one; smooth. Palps paired; unarticulated; ventrolateral. Nuchal organs indistinct paired dorsolateral patches. Peristomial ring absent.
Pharynx & pharyngeal apparatus. Foregut a muscular axial pharynx; with two pairs of jaws; fang-like; distal ring of papillae present.
Body segments & parapodia. First segment chaetigerous (dorsal and ventral cirri enlarged and elongated). First chaetiger without external chaetae, or with notochaetae only; anteriorly directed and wrapping around head. Parapodia biramous with prominent parapodial lobes; notopodial lobes represented by at least one chaetal lobe; neuropodial lobes represented by at least one chaetal lobe. Dorsal cirri modified as elytra (may include cirriform ones as well). Elytra smooth or ornamented, without concentric rings; occur on alternate chaetigers throughout the body. Ventral cirri present, cirriform or tapering. Branchiae absent, or present; arise from parapodia; occur on at least some chaetigerous segments; digitiform, or branching.
Chaetae. Notochaetae present. Aciculae present; in both dorsal and ventral positions (=noto- and neuroaciculae). Capillary chaetae hair-like; spinose. Silky fibre-like chaetae present (in notopodia). Spines present in most or all chaetigers; in neuropodia only; with series of rings or half-rings of spinelets. Hooks absent.
Tube & burrow. Tube membraneous (mud embedded with silk-like chaetae).

The above description was generated from: 'C.J. Glasby & K. Fauchald (2002 onwards). POLiKEY. An information system for polychaete families and higher taxa: Version 1: September 2002.'
(See ABRS website: Online Resources: Polikey, for Version 2, released June 2003)