Diplocirrus micans Fauchald, 1972

Salazar-Vallejo, Sergio I. & Buzhinskaja, Galina, 2011, Revision of Diplocirrus Haase, 1915, including Bradiella Rullier, 1965, and Diversibranchius Buzhinskaja, 1993 (Polychaeta, Flabelligeridae), ZooKeys 106, pp. 1-45 : 26-28

Diplocirrus micans Fauchald, 1972 Fig. 8

Diplocirrus micans Fauchald 1972:218-219, Pl. 44, Figs. a–e; Darbyshire and Mackie 2009:97, Table 1.

Type material.

Eastern Pacific Ocean. Holotype (LACM-AHF992), off Natividad Island, Baja California, RV Velero IV, Stat. 7229 (27°54'25"N, 115°40'00"W), 957-942 fathoms, 31 Dec. 1960.

Additional material.

Eastern Pacific Ocean. Several fragments (LACM-AHF 2615), off Natividad Island, Baja California, RV Velero IV, Stat. 7231 (from 27°24'00"N, 115°12'15"W, to 27°23'17"N, 115°13'45"W), 1355-1312 fathoms, green mud, 1 Jan. 1961. Median fragment (LACM-AHF 2612), off Natividad Island, Baja California, RV Velero IV, Stat. 7249 (27°36'25"N, 115°56'25"W), 2050-2027 fathoms, red clay and rock, 4 Jan. 1961. Two specimens (LACM-AHF 2611), 44 miles, 192 degrees N from Cabo Corrientes Lighthouse, RV Velero IV, Stat. 13754-70 (19°41"15"N, 105°53 ’00” W), 1220 fathoms, Campbell grab, 18 Jan 1970 (25-30 mm long, 1.2-1.5 mm wide, cephalic cage 1.5-3.0 mm long; chaetiger 1 with 2-3 noto- and 5-6 neurochaetae per bundle, 39 chaetigers; female with oocytes 125 µm). An anterior fragment (LACM-AHF 2611a), 35.3 miles 205 degrees T (T=true north) from Cabo Corrientes Lighthouse, RV Velero IV, Stat. 13755-70 (19°51'30"N, 105°58'00"W), 1400 fathoms, Campbell grab, 18 Jan 1970 (7 mm long, 1.5 mm wide, cephalic cage chaetae 7 mm long; chaetiger 1 with 4-5 noto- and 5-6 neurochaetae).

Description.

Holotype pale, damaged, without posterior end (in regeneration?), several parapodia removed, many chaetae broken. Body slightly swollen anteriorly, tapering posteriorly (Fig. 8A); 11 mm long, 1 mm wide, cephalic cage 1 mm long, 26 chaetigers. Tunic papillated, with abundant, fine sediment particles adhered. Papillae short, abundant (most eroded), cylindrical, longer in first chaetiger and in chaetal lobes, less than 1/3 chaetal length (very long in LACM-AHF 2615, as long as half notochaetal length).

Anterior end not exposed; not dissected to avoid further damage. Cephalic cage chaetae as long as body width. Chaetigers 1-2 involved in the cephalic cage; chaetae arranged in short, lateral lines, 2 chaetae per ramus. Anterior dorsal margin of first chaetiger papillated. Anterior chaetigers without long papillae. Chaetigers 1-3 progressively larger; notopodia with suprachaetal conical lobes. Post-cephalic cage chaetigers not elongated. Chaetal transition from cephalic cage to body chaetae abrupt; multiarticulared neurochaetae start in chaetiger 3. Gonopodial lobes not seen (Fig. 8B).

Parapodia porly-developed, chaetae emerge from the body wall (Fig. 8D). Parapodia lateral; median neuropodia ventrolateral. Noto- and neuropodia low, rounded lobes, very close to each other. All notochaetae multiarticulated capillaries, articles short basally, become long medially and distally (Fig. 8E). Median notochaetae arranged in a short, transverse line, holotype with 2-3 per bundle (other specimens with 8-9 chaetae per bundle), twice as long as body width. Neurochaetae multiarticulated capillaries in chaetigers 1-2; multiarticulated, thicker neurospines start in chaetiger 3, arranged in a transverse line, 4 per bundle (up to 8 in larger fragments Stat. 7231). Neurochaetae with short articles basally, become long medially, slightly decreasing their length distally; tips slightly falcate (Fig. 8F).

Posterior end unknown.

Remarks.

Diplocirrus micans Fauchald, 1972 resembles other species with abundant papillae and long chaetae such as Diplocirrus longisetosus (von Marenzeller, 1890), and Diplocirrus normani (McIntosh, 1908), comb. n. However, Diplocirrus micans separates from the two other species because its neurochaetae have long articles, and there are no gonopodial lobes, whereas the two other species have distal articles barely longer than wide, and gonopodial lobes.

The record by Fauchald and Hancock (1981:36) was based on a single, damaged specimen collected off Oregon, United States. The specimen (LACM-AHF 2616) resembles Diplocirrus micans but it is brittle, apparently it has dried out in the past, so the conical lobes in first few chaetigers cannot be confirmed. However, this specimen has many more chaetae per bundle, especially in the anterior end, and articles are much longer than in Diplocirrus micans , so it may be a different species, but the specimen is in poor shape and more specimens are required to describe it.

Distribution.

Western Mexico, in deep water (1900-2800 m depth).