Syllis armillaris is one of the largest syllids in Norwegian waters and the most common syllid in Norwegian ports. It is characterised by having the dorsum with dark transverse stripes in the anterior end. 


Up to 3 cm and with up to 140 segments.


Some specimens can be quite large. The main characteristic is the pigmentation pattern, with two transverse dark brown pigment bands on each segment, particularly clear in the anterior end. The head has four rather small eyes and two small eye spots. The palps are large and fused at the base. The three antennas are about the same length and have 11–13 segments. The dorsal cirri are similar in length throughout the body and have 8–12 segments. The compound chaetae have shafts of medium length. 


This species is characteristic by the two dark transverse bands in the dorsum of each segment. However, there are also some other Syllis species in the Northeast Atlantic showing this pattern, for example Syllis fasciata, which is common in Northern Norway, Syllis khronii, reported from the North Sea to the Mediterranean, and Syllis gracilis, cosmopolitan in temperate seas also in Europe. These species can be distinguished by the chaetal morphology among other features, which needs detailed examination under a compound microscope. In addition, Syllis armillaris is the most common species of all these in southern Norway port environments.

Biology, ecology and behaviour

It feeds on unicellular and multicellular algae, and also some animals. The species is a broadcast spawner. Gametes can be differentiated in the adults, the eggs are violet and the sperm yellow to pink. 


Syllis armillaris is common on hard bottoms from a depth of three meters and below. It is reported as a cosmopolitan, but the type locality is in the North East Atlantic.

Recommended citation

Capa M. Syllis armillaris (O.F. Müller, 1776). Downloaded <year-month-day>.