Chaetozone setosa Malmgren, 1867

Synonyms:
No synonyms.

Distinguishing characteristics
Pair of thick palps and one filamentous branchia dorsally on notopodia.
Very long capillary chaetae present from approx. 20th chaetiger.
Posterior chaetigers with thick spines in a nearly complete ring around the segments.

Species description
Body long, cylindrical. Prostomium a sharp cone, without eyes. Peristomium achaetous, partially divided into 3 annuli. Pair of grooved tentacular palps originating from dorsal surface of posterior annulus. Long filamentous branchiae arising posterior to bases of palps, absent on posterior third of body. Anterior segments with long capillary chaetae, mid-body parapodia with long chaetae dorsally and ventrally thicker capillaries and spines. Very long capillary chaetae (2-3 times body width) present from approx. 20th chaetiger. Posterior chaetigers with 6-8 thick spines in noto- and neuropodia forming a nearly complete ring around the segments. Well-defined constrictions (about half of chaetiger width) between posterior chaetigers. Pygidium with very small flat rounded ventral lobe.

Size
Up to 25 mm for 90 segments.

Color
Bright or dark grey, brownish- or bluish-black.

Habitat
On muddy bottoms in the shallow sublittoral.

Mobility
Sedentary.

Feeding
Surface deposit feeder.
Facultative suspension feeder.

Life cycle
Non-pelagic larvae.

Distribution
Whole North Sea, Skagerrak, Kattegat to Baltic Sea, Arctic to Mediterranean.