(M. Sars, 1861)
Description:
A scale-worm with a body of uniform width. Dorsal and ventral surfaces smooth.
Prostomium bilobed with a peak on each lobe; median and lateral antennae papillated on the terminal portions and a pair of palps. Two pairs of eyes, the anterior pair on the line of greatest width, the posterior pair in front of the rear margin.
First segment bearing chaetae and a pair of dorsal and ventral tentacular cirri. Scales overlap covering the body. Scales are oval to round with a few papillae on the margins, and a surface covered with coarse wart-like protuberances and pointed bifid and floret tubercles, becoming increasingly larger towards the posterior border.
Notopodia are small mounds with a ventral acicular ligule and numerous chaetae. Notopodial chaetae stout with rows of spines and blunt tips. Neuropodia well developed with an anterior ligule and numerous chaetae. Neuropodial chaetae of 2 kinds: 1) upper and lower group with rows of spines and unidentate tips; 2) median group bidentate with minute secondary tooth (A. asperrima-detail).
Size:
Up to 25 mm for 41 chaetigers.
Colour:
Brownish.
Habitat:
Sublittoral to 1420 m
Distribution:
North Atlantic up to the Azores, northern North Sea to Skagerrak (Oslofjord).