Family NERILLIDAE

Nerillidae

© Copyright Greg Rouse

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Introduction

Nerillids are minute worms (rarely exceeding 2 mm) that mainly inhabit the interstitial spaces of intertidal and subtidal sediments such as sand, shell or gravel, and seem to prefer temperate and tropical waters. They apparently browse diatoms and bacteria from sediment particles, but little is known of their biology or ecology. They are transparent when alive, with a coloured gut and bright eye spots.

Figures of 1 genus and 2 species were given by Beesley et al. (2000: App. 1) for representation of the family in Australian waters, and 18 genera and 42 species worldwide. Many of the taxa are from northern Europe, but this is almost certainly a reflection of the additional collecting effort that has taken place there. Systematic studies of interstitial faunas are scarce in Australia so it is little wonder that Nerilla australis, from salt marshes in Western Port in Victoria, is the only described Australian species. A second species, apparently undescribed, has been collected from a cave on Christmas Island (R.Wilson, unpublished observation).

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

Database Notes

proof read against Day & Hutchings 1979 by RW; no subsequent records added
checked against DELTA CD 2003 by RTJ

Diagnosis

General features. Body shape grub-shaped; segments few (typically 7 to 14); regionation absent. Body more-or-less transparent, gut visible. 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). Eyes absent, or present; one pair, or two pairs; situated on prostomium; without lenses. Prostomial antennae present; include paired anterolateral ones and single medial one; smooth, or articulated. Palps absent, or paired; unarticulated; ventrolateral. Nuchal organs indistinct paired dorsolateral patches. Peristomial ring absent.
Pharynx & pharyngeal apparatus. Foregut a ventral pharyngeal organ; dorsolateral ciliated folds present.
Body segments & parapodia. First segment chaetigerous, or with tentacular cirri. Tentacular cirri 1 pair(s); arise on a single segment; internal aciculae absent. First chaetiger with neurochaetae only, or with both notochaetae and neurochaetae. Parapodia biramous with parapodial lobes absent or low; notopodial lobes represented by at least one chaetal lobe; neuropodial lobes represented by at least one chaetal lobe. Interramal fleshy process present, cirrus-like (the only distinct parapodial lobe). Dorsal cirri absent. Ventral cirri absent. Branchiae absent.
Chaetae. Notochaetae present. Aciculae absent. Capillary chaetae hair-like; smooth. Spines absent. Hooks absent. Compound chaetae present; appendage distally tapering to slender tips (=spinigerous); appendage not canaliculated; appendage without hoods or guards; joint distinctly asymmetrical (=heterogomph); joint effected by ligament(s); shaft tapering slightly or evenly thick from emergence to joint; shaft without distinct core. Compound falcigers present in most or all chaetigers.

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)

General References

Beesley, P.L., Ross, G.J.B. & Glasby, C.J. (eds) 2000. Polychaetes & Allies: The Southern Synthesis. Fauna of Australia Vol. 4A Polychaeta, Myzostomida, Pogonophora, Echiura, Sipuncula. Melbourne : CSIRO Publishing Vol. 4 Part A xii 1-465 pp.

Paxton, H. 2000. Family Nerillidae. pp. 170-171 in Beesley, P.L., Ross, G.J.B. & Glasby, C.J. (eds). Polychaetes & Allies: The Southern Synthesis. Fauna of Australia Vol. 4A Polychaeta, Myzostomida, Pogonophora, Echiura, Sipuncula. Melbourne : CSIRO Publishing Vol. 4 Part A xii 1-465 pp.

History of changes