Type species: Harmothoe spinosa Kinberg, 1856.
Diagnosis (from Barnich & Fiege (2009)). Body dorsoventrally flattened, short, with up to about 50 segments; dorsum more or less covered by elytra or short tail region uncovered. Fifteen pairs of elytra on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 26, 29, 32. Prostomium with distinct cephalic peaks and three antennae; lateral antennae inserted ventrally to median antenna. Position of anterior pair of eyes variable, posterior pair situated dorsally near hind margin. Parapodia with elongate acicular lobes with both acicula penetrating epidermis; neuropodia with a supra-acicular process. Notochaetae stout with distinct rows of spines and blunt tip. Neurochaetae more numerous and usually more slender; with distinct rows of spines distally and tips falcate or straight, either all bidentate with a subdistal secondary tooth or some bi- and some unidentate.