Mariansabellaria, KIRTLEY, 1994

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 : 263

MARIANSABELLARIA KIRTLEY, 1994

Mariansabellaria Kirtley, 1994: 136–137 . Type species: Phalacrostemma norvegicum Strømgren, 1971 , by monotypy. Type locality: Bindalsfjiorden, Norway.

Diagnosis: Mariansabellaria is characterized by the following combination of features: presence of straight nuchal spines, very long palps, branchiae on the second segments, and the absence of a median organ. Members of the genus have a conspicuous ventral glandular area on the parathoracic segments ( Kirtley, 1994), a potential autapomorphy for the group.

Description: Operculum longer than wide with lobes completely divided into two symmetrical halves and distal disc perpendicular to longitudinal axis; long conical papillae around its perimeter. Outer paleae, arranged in semicircles, smooth, straight and cylindrical or slightly flattened. Inner paleae, few in number, arranged in a short single row near the dorsal junction of margin of lobes, straight. One or more pairs of nuchal spines. Palps grooved and longer than operculum. Tentacular filaments arranged in single rows. Buccal flaps absent. Conspicuous median organ absent. Neuropodia of segment 1 with one cirrus on each side of building organ; capillary neurochaetae absent. One or two triangular lateral lobes on segment 2. Thoracic branchiae absent. Four parathoracic segments. Parathoracic notochaetae lanceolate and capillaries alternating; neurochaetae only capillaries. Abdominal branchiae present on anterior abdominal segments but not on posterior ones.

Remarks: Mariansabellaria was characterized by the presence of conspicuous ventral glandular areas on the parathoracic segments ( Kirtley, 1994) but this feature is not described in all species of the genus or in other sabellariids and therefore needs confirmation. Mariansabellaria shares with Bathysabellaria , Gesaia , Phalacrostemma , and Tetreres the occurrence of a long operculum with perpendicular disc, long opercular papillae and single tentacular filaments without buccal flaps. However, only Gesaia , Mariansabellaria , and Tetreres have parathoracic neuropodia with just capillary chaetae. Close relationships between Mariansabellaria and Tetreres are based on the size of palps, exceeding the length of the operculum. Mariansabellaria is distinguished of these taxa by the presence of straight nuchal spines. This genus is represented by four species from the west coast of North and South America and also Norway, at depths ranging from 180 to 2000 m.