Description: Body slender, cylindrical; covered by small papillae. Prostomium broadly rounded, without eyes. Peristomium dorsally not visible. Palps unknown. 2 pair of thread-like gills on the second segment. One large oval papilla present, laterally below gills on second segment (M. polyonyx-head). The first chaetiger with 2, second with 2-3 and next chaetigers with 3-5 finely denticulate capillary chaetae on notopodia. Ventrally 5-6 compound chaetae from the 4th segment (M. polyonyx-chaetae). Pygidium unknown.
Size: Up to about 12 mm for 36 segments (incomplete).
Colour: Anterior edge of the prostomium and segments without chaetae with pigmentation, anterior chaetigers with broad brown cross-bands.
Habitat: 235-478 m.
Distribution: Northern North Sea (60° N), Skagerrak.
Kingdom Animalia Phylum Annelida Class Polychaeta Order Flabelligerida Family Acrocirridae Genus Macrochaeta Species Macrochaeta polyonyx
