Diplocirrus kudenovi, Salazar-Vallejo, Sergio I. & Buzhinskaja, Galina, 2011

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 : 21-24

Diplocirrus kudenovi sp. n. Fig. 6

Type material.

Eastern Pacific Ocean. Holotype (LACM-AHF 2594) and 14 paratypes (LACM-AHF 2595), Southern Bay, Isla Cedros, Baja California, Mexico, RV Velero IV, Stat. 2026 (20°05'00"N, 115°19'45"W), 16 fathoms, mud and sand, 19 Apr. 1951 (best paratypes: 8.0-22.5 mm long, 1-2 mm wide, cephalic cage 1.0-1.5 mm long, 24-49 chaetigers).

Additional material.

Gulf of California. One anterior fragment (LACM-AHF 2596), damaged, off southeastern tip of Isla Angel de la Guarda, Baja California, Mexico, Stat. P-71-59 (29°20.0'N, 113°11.2'W), 40 fathoms (7 mm long, 1.5 mm wide, cephalic cage 1.5 mm long, 19 chaetigers).

Description.

Holotype (LACM-AHF2594), without posterior end, soft, whitish (Fig. 6A). Body club-shaped, anteriorly swollen, progressively narrowing to chaetiger 15, then cylindrical, tapering to the end of the fragment; 19 mm long, 2 mm wide, cephalic cage 1.5 mm long, 47 chaetigers. Tunic papillated, fine sediment particles on papillae basis only. Papillae short, abundant, capitate, with basal sediment making a rounded lobe, about 13-15 irregular rows in anterior chaetigers (about 10 rows in median chaetigers), slightly longer dorsally and in posterior chaetigers; in median chaetigers papillae as long as 1/5-1/6 notochaetal length.

Anterior end completely exposed, slightly damaged (Fig. 6B). Cephalic hood short, smooth, margin smooth. Prostomium low, pale, eyes not seen. Caruncle poorly developed, lateral ridges low, median keel reduced, not continued to the posterior margin of the branchial plate (Fig. 6C). Palps lost in holotype (pale in one paratype), palp bases rounded. Lateral lips well developed, dorsal lip reduced, ventral lip rounded. Branchiae mostly lost, branchial scars on branchial plate, arranged in two rows, posterior row with 4 thicker branchial scars, anterior row discontinuous, two narrower branchial scars, one long cirriform branchia left. Nephridial lobes rounded, separating posterior and anterior branchiae.

Cephalic cage chaetae shorter than body width. Chaetiger 1 involved in the cephalic cage, slightly displaced dorsally; chaetae arranged in short dorsolateral lines, with 2 noto- and 4 (-6) neurochaetae. Anterior dorsal margin of first chaetiger papillated; anterior chaetigers without especially long papillae. Chaetigers 1-3 progressively larger. No chaetal transition from cephalic cage to body chaetae, all neurochaetae similar, but first chaetiger with shorter articles. Gonopodial lobes present in chaetiger 5 (or 5 and 6 in some paratypes), a transverse papillae-free area.

Parapodia lateral, poorly-developed, chaetae emerge from the body wall (Fig. 6E); median neuropodia ventrolateral. Notopodia without conical chaetal lobes. Noto- and neuropodia distant to each other.

Median notochaetae arranged in a longitudinal, short line; all notochaetae multiarticulated capillaries, short articles basally, long medially and distally (Fig. 6F). About 6-8 chaetae per bundle, 1/2-2/3 as long as body width. All neurochaetae multiarticulated hooks, feebly-defined short articles basally, medial- and distally with long articles, distally falcate (Fig. 6G); neurohooks arranged in a transverse line, with 5-6 per bundle.

Posterior end (observed in a paratype) tapering to a rounded lobe (Fig. 6D); pygidium with anus terminodorsal, without anal cirri.

Etymology.

This species is named after Jerry D. Kudenov, who has studied several polychaete families on a world-wide basis, and especially for his series of publications on the polychaetes from the Gulf of California, which have been very useful for many researchers working in the region, including one of us (SISV). The epithet is a noun in the genitive case.

Type locality.

Southern Bay, Isla Cedros, Baja California, México, in mud-sand bottoms, at 16 fathoms depth.

Remarks.

Diplocirrus kudenovi sp. n. is very similar to Diplocirrus stopbowitzi Darbyshire & Mackie, 2009, because both have bodies without sand particles, with papillae hemispherical, and by lacking ventrolateral gonopores. They differ in chaetal features, especially regarding neurochaetae; thus, in Diplocirrus kudenovi , median chaetigers have 5-6 neu rochaetae and each has articles about twice as long as wide, whereas in Diplocirrus stopbowitzi , there are 2-3 neurochaetae and each has longer articles, being about seven times longer than wide.

Distribution.

Western Mexico, in both sides of the Baja California Peninsula, in subtidal waters.