Flabelligera orensanzi, Salazar-Vallejo, 2012

Salazar-Vallejo, Sergio I., 2012, Revision of Flabelligera Sars, 1829 (Polychaeta: Flabelligeridae) 3203, Zootaxa 3203 (1), pp. 1-64 : 27-29

Flabelligera orensanzi n. sp.

Figure 10

Flabelligera affinis: Rullier & Amoureux 1979:183 (non Sars, 1829).

Type material. Southwestern Atlantic Ocean. Holotype (MACN-In 39270) and paratypes ( CENPAT), Cruise of R/ V Sanjo I, off San Roman, among scallops, 4–5 fathoms, 5 May 1976, J.M. Orensanz, coll. (paratypes one large anterior fragment 18 mm long, 4.5 mm wide, cephalic cage 4 mm long, 20 chaetigers, and other median fragments). Two paratypes ( ECOSUR), one complete with tunic slightly damaged, and one anterior and another posterior fragments, Cruise of R/ V Sanjo I, Punto Tehuelche, on scallops, 6 May 1976, J.M. Orensanz, coll.

Additional material. Southwestern Atlantic Ocean. Three specimens ( CENPAT- 00GSJ), one complete without tunic, and two fragments, Golfo San José, San Román, on scallops, Mar. 1976, J. M. Orensanz, coll. Two specimens ( CENPAT- 00GSJ2), one complete with regenerating pygidium and an anterior fragment, without tunic, Golfo San José, R / V Sanjo II, off El Riacho, May 1976, J. M. Orensanz, coll. One specimen ( MNHN-884 ), tunic removed, most cephalic cage chaetae and some parapodia dissected, head appendages lost, R/V Calypso, Stat. 24 (08º23' S, 34º42' W), 51 m, sand, 21 Nov. 1961 (two copepods on the head) .

Description. Holotype (MACN-In 39270) almost complete, without posterior end, pale, medially swollen, tapering towards both ends ( Fig. 10A ); 22 mm long, 2 mm wide, cephalic cage 3.5 mm long, 22 chaetigers. Tunic transparent with thin, irregular layer of fine sediment particles; papillae long, distally swollen, some mucronate.

Cephalic hood not exposed. Anterior end observed in paratype ( Fig. 10C ). Prostomium low cone, partially eroded, with four large, barely pigmented eyes. Caruncle well developed, extended well beyond the branchial plate margin; medial lobe elevated, barely pigmented; lateral lobes rounded, pale. Palps pale, contracted, as long as branchiae; palp bases elevated, rounded. Lateral lips well developed, projected forward as two rounded lobes; dorsal lip projected inside the mouth; ventral lip reduced. Ventral pharyngeal organ exposed.

Branchiae in two lateral groups, each group with about 100 branchial filaments in 7–8 rows;, longer filaments as long as palps, decreasing in size ventrally. Nephridial lobes cirriform, base flat, tapering in a long, blackish nephridial tube.

Cephalic cage chaetae about twice as long as body width. Chaetiger 1 involved in the cephalic cage, about 40 noto- and 26 neurochaetae per side. Chaetal transition from cephalic cage to body chaetae abrupt; multiarticulate neurohooks from chaetiger 2. Anterior dorsal margin of first chaetiger papillated. Anterior chaetigers without especially long papillae. Chaetigers 1–3 decreasing in size posteriorly. Gonopodial lobes not seen.

Parapodia well developed, lateral; median neuropodia ventrolateral. Notopodia foliose, barely pigmented distally. Neuropodia conical, barely pigmented distally.

Median notochaetae arranged in short transverse rows; all notochaetae multiarticulated capillaries, about as long as body width, 9–10 per fascicle, most with short articles basally, becoming alternate or longer medially and distally. Neurochaetae multiarticulated capillaries in chaetiger 1; single, multiarticulated hooks from chaetiger 2 ( Fig. 10D ). Handle articulation basally placed, articles irregular (Fibonacci); two articles: medium sized and long. Other articles anchylosed, barely visible along median region. Crest slightly wider than handle, dark brown along the body, with darker distal half; width:length ratio 1:4.

Posterior end missing in holotype; paratype and non-type specimen ( CENPAT- 00X, CENPAT- 00GSJ) tapered posteriorly, pygidium cylindrical, with anus terminal, rounded, without anal cirri .

Etymology. This species is dedicated to my good friend and teacher, José M. ‘Lobo’ Orensanz, as a humble recognition of his many fine publications on Southern Atlantic Ocean polychaetes, and for providing support and sharing expertise during my academic activities in Chetumal and elsewhere.

Remarks. Flabelligera orensanzi n. sp. resembles F. affinis . They differ because in F. orensanzi n. sp. the tunic has a slight sediment cover and the neurohook crests are medially widened and dark red, whereas in F. affinis the tunic is free from sediment particles and the neurohook crests are pale and tapered, not medially widened.

One specimen (MNHN-884) has two copepod parasites on its cephalic hood inner margin ( Fig. 10E ). They resemble those present in F. diplochaitus (see above) and might belong to the same genus.

Type locality. Off San Roman , Argentina, in shallow sandy bottoms with scallops .

Distribution. Only known from few localities off Central Argentina, in shallow depths on scallop bottoms.

Figures

FIGURE 10. Flabelligera orensanzi n. sp. A. Holotype (MACN-In 39270), dorsal view. B. Same, anterior end, ventral view. C. Paratype (CENPAT), head, frontal view, palps and branchiae removed, prostomium slightly eroded (BS: branchial scars, LL: lateral lip, PS: palp scar). D. Paratype (ECOSUR), chaetiger 9, neurohook (insert: articulated region of handle). E. Non-type specimen (MNHN-884), head, frontal view, two copepod parasites indicated by arrows (Ca: caruncle, BS: branchial scar, VL: ventral lip). Scale bars: A: 0.8 mm, B: 1 mm, C: 0.5 mm, D: 225 µm, E: 0.25 mm.