Lygdamis, KINBERG, 1867

Capa, María, Hutchings, Pat & Peart, Rachael, 2012, Systematic revision of Sabellariidae (Polychaeta) and their relationships with other polychaetes using morphological and DNA sequence data, Zoological Journal of the Linnean Society 164 (2), pp. 245-284 : 261-263

LYGDAMIS KINBERG, 1867

Lygdamis Kirtley, 1994: 116 .

Type species: Lygdamis indicus Kinberg, 1867 by monotypy. Type locality: Bangka Straits , Java, Indonesia .

Diagnosis: The monophyly of the genus has not being assessed in the phylogenetic analyses although all species assigned to Lygdamis have an operculum with separated lobes and distal end sloped posteriorly, opercular paleae straight and smooth, the outer ones being flattened and the inner ones cylindrical, resembling spines.

Description: Operculum longer than wide with lobes completely separated and distal end sloped posteriorly (oblique to longitudinal axis). Numerous opercular papillae around edge of lobes. Outer paleae arranged in semicircles, straight, with flat blades, lateral and distal margins smooth. Inner opercular chaetae arranged in one row along the inner margin ·

of opercular lobes with straight and cylindrical or slightly flattened blades. One pair of nuchal spines with bent tips (hooks) and without limbations. Palps similar in size to the operculum. Median organ elongate at the dorsal junction of the lobes of the opercular stalk. Tentacular filaments compound (branching); buccal flaps absent. Neuropodia of segment 1 with a conical cirrus, with or without capillary chaetae. Segment 2 with three triangular-shaped lobes between noto- and neuropodia, in some species rounded and small. Four parathoracic segments with notochaetae consisting of lanceolate and capillary chaetae and neurochaetae similar in shape but smaller. Branchiae from segment 2 to mid abdominal segments.

Remarks: According to our analyses this genus is not monophyletic but this is probably an artefact of splitting the paleal types into different categories according to their ornamentation, shape, and angle. All Lygdamis species have an operculum with a distal end sloped posteriorly and opercular paleae straight and smooth, the outer ones being flattened and the inner ones cylindrical. Some variation included the shape of lateral lobes of segment 2, the presence or absence of neurochaetae in segment 2, and the presence of eyes near the median organ. This genus shares several features with Idanthyrsus but differences are the number of parathoracic segments, the shape of outer paleae (strongly denticulated in Idanthyrsus and smooth in Lygdamis ), and the presence of capillary chaetae alternating with the lanceolate chaetae on the neuropodia of parathoracic segments of Lygdamis , the latter type being the only ones present in Idanthyrsus species. The genus is known from 16 species ( Kirtley, 1994).