Diplocirrus erythroporus Gallardo, 1968

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 : 17-19

Diplocirrus erythroporus Gallardo, 1968 Fig. 3

Diplocirrus erythroporus Gallardo 1968:108, Pl. 49, Figs. 7-10; Darbyshire and Mackie 2009:97, Table 1.

Diplocirrus glaucus : Fauvel 1932:186-187; Fauvel 1953:353, Fig. 184 a–d (non Haase, 1915).

Diplocirrus glaucus orientalis Gibbs 1971:181, no figs.

Type material.

Viet Nam. Holotype (LACM-AHF 306), off Hon Mot Island (12°10'34"N, 109°16'11"E), R.V. Mao Tien, Naga Expedition Stat. 113, 22 m, 10 Feb. 1960.

Additional material.

Viet Nam. Two specimens (LACM-AHF 2606), Western side of Hon Lon Island (12°12'49"N, 109°14'22"E), R.V. Mao Tien, Naga Expedition Stat. 323, 14 m, 4 Apr. 1960.Australia. Two specimens (NTM-18920), one complete, the other without anterior end, Stat. DW69A (12°32.28'S, 130°46.66'E), Darwin Harbor, Australia, 3 m, 17 Mar. 1994, Marine Ecology Unit, coll. (complete: 34 mm long, 3 mm wide, cephalic cage 1.8 mm long, 64 chaetigers, gonopores in chaetigers 4-14). Yellow Sea. Anterior fragment (ZISP-10854), plus few chaetigers, Yellow Sea, R.V. Venus, no station data, Chzhan coll.; B. Wu id. as Brada longicirrata sp. n. It was 11 mm long, 2 mm wide, cephalic cage 1.5 mm long, 23 chaetigers; four large erect papillae on chaetigers 1-2, one per ramus (resembling a cirrus on each chaetal bundle and hence the name); dorsal ones rise behind the first chaetiger notochaetae whereas the ventral ones stem halfway between the neurochaetae of chaetigers 1 and 2; nephridial pores without pigmentation, in chaetigers 4-12.

Description.

Holotype an anterior fragment, soft, pale, with dispersed dark brown spots (Fig. 3A). Body cylindrical, anteriorly swollen, posteriorly tapered; 19 mm long, 2.8 mm wide (by chaetiger 7), cephalic cage 0.9 mm long, 33 chaetigers. Tunic papillated, with fine sediment particles.

Cephalic hood exposed, paler than following segments, almost transparent, with smaller papillae; anterior margin papillated, papillae sparse (anterior end dissected in another specimen, LACM-AHF 2606). Prostomium low cone (Fig. 3C); eyes not seen. Caruncle not seen. Palps pale; palp keels reduced. Branchiae of two types, distal row with filaments thick, cirriform; proximal branchiae in two lateral groups, filaments cirriform, thinner, with a thin distal part. Branchiae shorter than palps. Nephridial lobes rounded, low, brownish.

Cephalic cage chaetae as long as 1/3 body width. Only chaetiger 1 involved in the cephalic cage, slightly displaced dorsally. Chaetae arranged in a short lateral line; 3-4 chaetae per ramus. Anterior dorsal margin of first chaetiger papillated, papillae similar to those along the body but with one pair of stiff, long notopodial papillae; posterior chaetigers without long papillae but slightly longer papillae restricted to chaetal lobes.

Chaetigers 1-3 of about the same length (NTM-18920 with chaetiger 2 very thin, chaetiger 3 much longer, almost without papillae). Post-cephalic cage chaetigers not elongated, but progressively widening reaching the widest dimension by chaetiger 7, and then posteriorly reduced. Chaetal transition from cephalic cage to body chaetae gradual; neurohooks start by chaetiger 10. No gonopodial lobes; orange-reddish, disk-shaped gonopores in chaetigers 4-12 (Fig. 3B); in larger specimens along chaetigers 4-14.

Parapodia reduced, chaetae emerge from the body wall (Fig. 3D, G). Parapodia lateral; median neuropodia ventrolateral. Notopodia and neuropodia with slightly longer papillae in chaetal lobes. Median notochaetae arranged in a tuft, oblique to body axis. Median notochaetae as long as ¼ body width, about 9 per bundle; all notochaetae multiarticulated capillaries, articles very short basally, longer medially, becoming medium-sized distally (Fig. 3E). Neurochaetae multiarticulated capillaries resembling no tochaetae in chaetigers 1-9; from chaetiger 10, neurochaetae thicker, multiarticulated hooks with short articles basally, becoming long medially, distal article longest, falcate, smooth (Fig. 3F). Median neurochaetae arranged in a transverse line, 4-5 per bundle.

Posterior end missing in holotype; non-type specimen (NTM-18920) with posterior end tapering to a blunt cone; pygidium with anus terminal, no anal cirri.

Remarks.

Diplocirrus erythroporus Gallardo, 1968 resembles Diplocirrus branchiatus (Rullier, 1965), comb. n. and Diplocirrus nicolaji (Buzhinskaja, 1994), comb. n. because they all have ventrolateral gonopores along some anterior chaetigers. However, these two latter species have very short chaetae in their first chaetiger, whereas Diplocirrus erythroporus has long chaetae. Additionaly, the caruncle of Diplocirrus erythroporus is posteriorly expanded unlike that of Diplocirrus branchiatus and Diplocirrus nicolaji .

The original description ( Gallardo 1968) was brief. It indicated that there were six tentacles (branchiae), four larger and two smaller ones, and there were no details on the extent of the cephalic cage. Thus, a redescription was required in order to separate this species from other similar ones in the Indo-Pacific regions. The two additional specimens were one maculated with rounded dark brown spots (11 mm long, 2.5 mm wide, cephalic cage 0.9 mm long, 22 chaetigers, gonopores in chaetigers 4-13), which was dissected to study the anterior end, and another without dark spots (14 mm long, 2.8 mm wide, cephalic cage 1.0 mm long, 23 chaetigers, nephridial pores in chaetigers 4-12; it is a mature female). Diplocirrus glaucus orientalis Gibbs, 1971 was described without illustrations; it has orange globular papillae below each neuropodium in chaetigers 4-14(16). This could include the record of Diplocirrus glaucus by Fauvel (1932:186-187, Fauvel 1953:353, Fig. 184 a–d). It is being regarded as a junior synonym of Diplocirrus erytrhoporus .

Distribution.

Vietnam, Solomon Islands, Northeastern Australia, in shallow depths (up to 24 m depth).