Chone diazi, Tovar-Hernández, María Ana, 2005

Tovar-Hernández, María Ana, 2005, Redescription of Chone americana Day, 1973 (Polychaeta: Sabellidae) and description of five new species from the Grand Caribbean Region, Zootaxa 1070, pp. 1-30 : 9-13

Chone diazi sp. nov.

Figures 3A–H, 4A–U

Material examined

Type material: Holotype [ FSBC I 66731], Paratypes [ FSBC I 66732] (2), [ECOSUR 0051] (1): Guacarapo, Golfo de Cariaco, Venezuela, 11° 37’ 30’’ N, 63° 45’ 05’’ W, 1 m, in PVC dock pilings among interstices covered by fine sand, bivalves, barnacles, sponges and cnidarians, Coll. O. Díaz, October 19, 1998.

Non­type material: Venezuela [ECOSUR], Mochima, Col. M. Liñero & O. Díaz, November 0 1, 2001 (1).

Additional material: Chone arenicola Langerhans, 1880 , holotype [ NMW 2286] Madeira, Ak IVr 1884/XIV/191, Alte Inv. Nr. 3375. Chone eniwetokensis ( Reish, 1968) , holotype [ USNM 38406] Eniwetok Atoll, Marshall islands, lagoon near Parry island, September 14, 1957, Coll. D. Reish. Chone princei McIntosh, 1916 , topotypes [ CMN 1989­0384] Quebec, St. Lawrence Estuary, off Trois Pistols, Sta. B130–70F–11D, 33 m, Coll. Rafat MASSAD, June 22, 1970 (6). [ CMN 1989–0385] Sta. BI 63–7 IL – 1210, 115 m, July 0 7, 1971 (15). [ CMN 1989–0386] off Trois Pistols, Sta. B167–70P–86D, 165 m, Coll. Rafat MASSAD, August 21, 1970 (30). [ CMN 1989–0387] off Point au Pire, Sta. B504–711–164B, 15 m, Coll. Rafat MASSAD, July 0 9, 1971 (3). [ CMN 1989–0390] off Point au Pire, Sta. B527–71H– 57, 220 m, Coll. Rafat MASSAD, June 17, 1971. [ CMN 1989–0391] off Granados Beyoerome, Sta. B94–15, 70L–61D, 274 m, Coll. Rafat MASSAD, June 30, 1970 (3).

Description (inside parentheses variation observed in paratypes)

Color, body shape and size: Body pink in life, pale in preserved material; cylindrical in thorax and anterior part of abdomen, depressed in posterior part of abdomen (Figure 3A); BoL= 10 mm (9.5–12), W= 1.3 mm (0.5–1.5).

Branchial crown: BrCL= 3 mm (2.5–3), RML/BrCL= 0.75/1. Radioles: 11 (9–10) pairs, broad flanges (Figures 3A, E), pinnules long, of similar length throughout radiole, RT= medium­sized [8 pinnules]. Radiolar skeleton composed of 2 rows of cells (Figure 3H) continued into pinnules (Figure 3E). BrL= small, completely exposed beyond collar (Figures 3A–C). DL= 3 times longer than wide (Figures 3F–G), without a discernable longitudinal ridge, with a basal plexus of blood vessels continuing distally as a single blood vessel (Figure 3G). VL= rounded, as long as wide, about one half of DL length (Figure 3F). VRA= 3 pairs, the inner one short, about one quarter of the BrCL; remainder long, about one half of the BrCL (Figure 3F).

Peristomium : APRL= completely exposed beyond collar (Figure 3B), ventral margin distally entire, long, triangular (Figure 3A). PPRC= antero­dorsal, lateral and ventral collar margins entire (Figure 3A–C), ventral slightly higher than dorsal (Figure 3C), dorsolateral pockets well developed (Figure 3C). VSC= swollen, horseshoe­shaped, 2 times wider than long (Figure 3A). PPRCL/ Ch 1L= 1/1.

Thorax: Chaetiger 1= Notopodia: two groups of 6 elongate, narrowly hooded chaetae. Chaetigers 2 to 8= Notopodia: SG= 2 rows of 6 elongate, narrowly hooded chaetae (Figures 4A–B); IG= 1 anterior row with 3 short bayonet chaetae (Figures 4C–D), 2 posterior rows with 6 symmetrical, paleate chaetae with short mucro (Figure 4E). Neuropodia: one row of 11–14 acicular uncini per torus, MF= 4, covering one half of the MF length (Figure 4F), teeth above MF unequal in size, basal tooth bigger than teeth in distal rows, hood present, handles long (Figure 4G). GR2= narrow, of same width around the segment (Figures 4A–C).

Abdomen: AS = 29. Anterior segments: 2 transverse rows of 10 elongate, narrowly hooded chaetae (Figures 4H–I), chaetae from the upper row 50% shorter than chaetae in lower row; 17–22 uncini per torus (Figure 4J), MF= 4, covering one half of the MF length, teeth above MF equal in size, breast rectangular, well developed, main fang not extending beyond breast, handles absent (Figures 4K–Q). Posterior segments: 2–3 modified, elongate, narrowly hooded chaetae, 25% longer than in anterior segments; 5–7 modified uncini per tori, MF= 7–8, covering three quarters of the MF length, teeth above MF equal in size, breast rectangular, poorly developed, main fang not extending beyond breast, handles absent (Figures 4R–U). Pygidium rounded, without cirrus (Figure 3D).

Gametes: Female paratypes with oocytes in thorax.

MGS: Solid color in ventral shield of collar, except in the distal end. Dorsally, second thoracic segment colored only in the anterior half, before GR2; following segments are divided by 2 dark rectangles except for the faecal groove. Ventrally solid color, except for intersegmental lines and both pre­ and post­chaetal lobes.

FIGURE 3. Chone diazi sp. nov. A) Whole worm, ventral view, B) anterior end, dorsal view, C) anterior end, lateral view, D) pygidium, lateral view, E) dorsal radiole, median region, lateral view, F) anterior end, lateral view, G) dorsal lip, H) radiolar skeleton, cross section, ventralmost pair, median region. A–D) Holotype FSBC I 66731, E–H) Paratype FSBC I 66732. aprl: anterior peristomial ring lobe, brl: branchial lobes, bs: branchial skeleton, bv: blood vessel, c: collar, dl: dorsal lip, fg: faecal groove, fl: flange, gr: glandular ridge, pe: peristomium , pi: pinnule, ps: pinnular skeleton, py: pygidium, rm: radiolar membrane, rs: radiolar skeleton, r d: dorsalmost radiole, r v: ventralmost radiole, vl: ventral lip, vra1: ventral radiolar appendage 1, vra2: ventral radiolar appendage 2, vra3: ventral radiolar appendage 3, vsc: ventral shield of collar.

FIGURE 4. Chone diazi sp. nov. A) Thoracic chaetae, segment 2, B) thoracic, elongate, narrowly hooded chaetae, C–D) bayonet chaetae, E) paleate chaetae, F) thoracic acicular uncinus, anterior end, G) whole thoracic acicular uncini, H) elongate, narrowly hooded chaeta, anterior abdominal segments, I) same, detail, J) abdominal tori, segment 13, K–Q) abdominal uncini, segment 13, R–U) abdominal uncini, last tori. A–U) Holotype FSBC I 66731. b: breast, d m: dorsalmost uncinus, h: hood, mf: main fang, v m: ventralmost uncinus.

Remarks: Chone diazi sp. nov. is unique among Caribbean species, by having the anterior peristomial ring lobe and branchial lobes exposed beyond the collar ( Table 1); however, Chone eniwetokensis ( Reish, 1968) described from the Marshall Islands, Chone arenicola Langerhans, 1880 from Madeira, Chone princei McIntosh, 1916 from the Gulf of Saint Lawrence, Canada, and Chone duneri Malmgren, 1867 from Norway, also share these characters. Chone diazi sp. nov. is unique among these species in having the ventral collar margin slightly higher than dorsal (notably higher than dorsal in C. arenicola , C. duneri , C. eniwetokensis and C. princei ) and broad flanges (narrow in others). Chone princei (CMN, topotype material) is unique in having the anterior peristomial ring lobe bilobed, two glandular shields located on the lateral sides of the anterior peristomial ring, and a longitudinal glandular band on the posterior part of abdomen. Chone eniwetokensis (USNM 38406, holotype) differs from these species because the paleate chaetae have a long mucro (short in others). Chone arenicola (NHMW 2286, holotype) and C. eniwetokensis have peristomial eyes (absent in C. diazi , C. duneri and C. princei ). Chone duneri is unique among them in having long radiolar tips (see Malmgren, 1867, pt. XIII, fig. 75B).

Species RML/ Flanges RT BrL and PPRCL/ GR2 MF of poste­ Pygidial BrCL APRL Ch 1L rior abdominal cirrus beyond uncinus

collar

C. americana 0.5/1 Narrow Long Not 1/1 Narrow Not extending Present

(20) exposed beyond breast

Etymology: This species is named after Óscar Díaz (Instituto de Investigaciones Oceanológicas, Cumaná, Venezuela), who collected the materials and kindly sent them to me for their identification.