Home | Overview | Browse families | Key to families

Identification tips
Natural History
Identification guide



Aeolosomatids are minute oligochaete-like worms which inhabit mostly freshwater. Like the similar potamodrilids they lack head appendages and parapodial lobes, but may be distinguished from them by the presence of coloured epidermal glands all over the body surface.

Aeolosomatids are minute, ciliated worms with no clear affinity to other polychaetes. The large, lobe-like prostomium is almost completely ciliated ventrally and has lateral ciliated grooves that have been interpreted as nuchal organs by Rouse & Fauchald (1997); the muscular pharynx lies in the peristomium. Constrictions along the trunk give the appearance of external segmentation, but they actually represent a chain of zooids produced by paratomy (fragmentation). Parapodia are absent. Chaetae are usually present as four bundles per segment; they are rarely absent. They comprise usually only capillaries, but in some species, some sigmoid hooks may be present, or, rarely, only hooks. The body is often brightly coloured due to the epidermal gland cells. Each gland cell consists of a vacuole, filled with red, green, blue-green, yellow, or sometimes colourless liquid; the function of the gland cells is unknown (Bunke 1988).

The above description is taken from Paxton (2000), which in turn is based on that of Fauchald & Rouse (1997).

The Aeolosomatidae, together with the Potamodrilidae, had been considered to be members of the Clitellata prior to the analysis of Rouse & Fauchald (1997) which placed them as provisional Polychaeta incertae sedis. However, further work may yet cause the Potamodrilidae and Aeolosomatidae to be removed back to the Clitellata (Rouse 2000).

Identification tips

Recognising the family
The Aeolosomatidae are apparently the only polychaete family which has epidermal glands present as discrete coloured spots. This family will be collected only when interstitial fauna is being sampled. This specialised habitat has been poorly sampled worldwide and especially in Australia.

Distinguishing species
Characters used to separate species of Aelosomatidae include the type of chaetae present (these include capillaries and sigmoid hooks), and the colour of the epidermal gland cells (which range from red, green, blue-green, yellow to colourless).


Description | Identification tips | Natural History | Diversity | Checklist | References | Identification guide