Family ACROCIRRIDAE

Museums

Museum list

Regional Maps

Family ACROCIRRIDAE

Compiler and date details

10 July 2003

Introduction

The Acrocirridae is a small family of sedentary, non-tubiculous, small thread-like or maggot-shaped worms. They are a poorly known group that occurs worldwide in soft sediments, from intertidal down to 5000 m depth. In feeding, the food particles are carried via the ciliated grooves of the palps to the mouth.

Figures of 2 genera and 2 species were given by Beesley et al. (2000: App. 1) for representation of the family in Australian waters, and 2 genera and 24 species worldwide. Acrocirrids were originally described as cirratulids, until Banse (1969) diagnosed a new family, Acrocirridae. Fauchald (1977) recognised 3 genera, whereas Banse (1969) recognised only 2 genera (Acrocirrus and Macrochaeta). Fauchald included the deep water genus Flabelligella, however, the inclusion of this genus in Acrocirridae has not been widely accepted.

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, or grub-shaped; segments numerous (more than about 15); regionation absent. Epidermis papillate, irregularly arranged papillae. Pygidium simple ring or cone. Pygidial appendages absent.
Head & head structures. Head discrete and compact, dorsal to mouth, or not clearly identifiable (may be retracted into anterior segments). Prostomium rounded to oval (anteriorly truncate), or narrow, keel- or ridge-shaped. Eyes absent, or present; three pairs; situated on prostomium; without lenses. Palps paired (often detached in preserved specimens); longitudinally grooved; dorsolateral. Nuchal organs indistinct paired dorsolateral patches. Peristomial ring single.
Pharynx & pharyngeal apparatus. Foregut a ventral pharyngeal organ.
Body segments & parapodia. First segment a smooth ring (usually first several segments lack parapodia or cirri). First chaetiger with neurochaetae only, or with both notochaetae and neurochaetae; more-or-less laterally directed and free from head, or anteriorly directed and wrapping around head (when prostomium retracted). 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. Dorsal cirri absent. Ventral cirri absent. Branchiae present; arise from dorsum; occur only on achaetous first segments, or occur on at least some chaetigerous segments; digitiform, or filiform.
Chaetae. Notochaetae present. Aciculae absent. Capillary chaetae hair-like; smooth, or hirsute-serrate. Spines absent. Hooks absent. Compound chaetae present; appendage distally curved (=falcate); appendage not canaliculated; appendage with a single hood open in front; joint flat or pseudocompound; joint effected by fold in external sheath of chaeta; shaft tapering slightly or evenly thick from emergence to joint; shaft without distinct core. Compound falcigers present in most or all chaetigers.
Tube & burrow. Tube absent or unconsolidated. Burrow traces absent.

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)