Piromis amoureuxi, Salazar-Vallejo, Sergio I., 2011

Salazar-Vallejo, Sergio I., 2011, Revision of Piromis Kinberg, 1867 and Pycnoderma Grube, 1877 (Polychaeta: Flabelligeridae), Zootaxa 2819, pp. 1-50 : 10-12

Piromis amoureuxi n. sp.

Figure 2

Piromis cf. roberti Amoureux, 1985:104 , Fig. 4 .

Type material. Caribbean Sea. Holotype (MNHN-900) and five paratypes (MNHN-900a) damaged, most sediment cover removed and many chaetae broken by screening or excessive brushing, Manche à l’eau Lagoon (16°16ʹ0 0ʺ N, 61°33ʹ0 0ʺ W), Guadeloupe Island, Nov. 1980.

Additional material. Caribbean Sea. Eight specimens (MNHN-914), seven anterior and one posterior fragments, preserved in alcohol, stained with Rose Bengal, Guadeloupe Island, without details about the collecting site or date. One specimen (ECOSUR-2/2001), Semarnat Pier, Cancun, Quintana Roo, Mexico, in purple sponge growing on sea-wall, 1 m, 18 Feb. 2001, P. Salazar coll.

Description. Holotype (MNHN-900) complete, pinkish due to overstaining with Rose Bengal, anteroventrally dissected, several parapodia removed ( Fig. 2 A). Body smooth with few sediment particles ( Fig. 2 B, C), possibly due to abrasion during sieving process; paratypes with large sediment particles on dorsal surface. Tunic thick, covering most body papillae; exposed papillae arranged in longitudinal rows, two dorsal and four ventral. Holotype 25.5 mm long, 2.5 mm wide, cephalic cage 3 mm long, 80 chaetigers.

Anterior end previously dissected in holotype, now lost (details based upon a paratype). Cephalic hood short, margin finely papillose. Prostomium low, pale, rounded, with dark brown eyes. Caruncle pale, well developed, extending to tip of branchial plate ( Fig. 2 D). Palps invaginated into mouth, contracted, distorting lips. Branchiae cirriform, arising from a short tongue-like protuberance, arranged in two lateral groups, each with branchiae arranged in about 11 oblique rows, basal ones longer, with more filaments, each group with about 80 filaments. Nephridial lobes not seen.

Cephalic cage chaetae about 1/8 as long as body length, or slightly longer than body width. Chaetigers 1–3 involved in the cephalic cage; chaetae arranged in short rows, dorsolateral in chaetiger 1, lateral in chaetigers 2–3; chaetiger 1 with 6–7 noto- and 3–4 neurochaetae per side, chaetigers 2–3 with 4–5 chaetae per fascicle. Anterior dorsal margin of chaetiger 1 with a multifid lobe, better preserved in non-type specimens, with 2–3 distal and two lateral projections. Anterior chaetigers with long papillae, chaetigers 2–6 with an elevated notopodial lobe. Chaetigers 1–3 progressively longer. Chaetal transition from cephalic cage to body chaetae abrupt; shorter multiarticulated bidentate neurohooks from chaetigers 6–7. Gonopodial lobes not seen.

Parapodia poorly developed, low rounded dorsal lobes in anterior chaetigers (2–6), reduced posteriorly. Parapodia lateral, median neuropodial ventrolateral. Noto- and neuropodia with long postchaetal capitate papillae; notopodia with 3–4, longest about 1/3–2/5 as long as notochaetae ( Fig. 2 E); neuropodia with three papillae.

Median notochaetae arranged in a transverse ∪-shaped row, 6–7 per bundle, about as long as 1/3 body width; all notochaetae multiarticulated capillaries, articles short basally, longer medially and distally ( Fig. 2 F), tips tapering. Neurochaetae multiarticulated capillaries in chaetigers 1–5; shorter multiarticulated bidentate neurohooks from chaetigers 6–7, arranged in a transverse row in anterior, median and posterior chaetigers ( Fig. 2 G); far posterior chaetigers with neurohooks in an oblique row ( Fig. 2 H), 4–5 per bundle throughout the body. Each neurohook with long articles basally, progressively decreasing in size; distal piece about as long as 1/5–1/6 neurohook length. Tip hooked, bidentate; accessory tooth not passing the fang.

Posterior end tapering, conical; pygidium contracted, anus ventral, without anal cirri.

Etymology. This species is named for Louis Amoureux, in recognition of his many studies on polychaetes, including some on Western Atlantic Ocean specimens, including the ones employed for this description.

Type locality. Manche à l’eau Lagoon, Guadeloupe Island, Lesser Antilles.

Variation. The paratypes are four anterior and one posterior fragments; the anterior fragments are 13–21 mm long, 0.8–2.8 mm wide, cephalic cage 2–3 mm long, 30–40 chaetigers.

Remarks. Piromis amoureuxi n. sp. is closely allied with P. brisegnoi n. sp. from the Gulf of California because both species have very few sediment grains along the body. They differ in the relative number and size of notochaetae, and in the shape of the distal article of neurohooks. Thus, in P. amoureuxi n. sp. the median notopodia have fewer (6–7) and shorter chaetae (about 1/3 as long as body width) than P. brisegnoi n. sp., which has more (about 10) and longer notochaetae (about 1/2 as long as body width). Further, the distal neurochaetal article in P. amoureuxi is straight, of about the same width throughout it, while in P. brisegnoi they are falcate and tapering.

Distribution. From the Northwestern Caribbean region to the Lesser Antilles, in shallow water fine sediments or in sediment pockets in some intertidal sponges.

Figures

FIGURE 2. Piromis amoureuxi n. sp. A. Holotype (MNHN- 900), twisted. B. Same, anterior end in dorsal view. C. Same, median segments in lateral view, showing sediment particles dorsally and laterally. D. Paratype (MNHN- 900 a), anterior end, palps and most branchiae detached (BD: branchial scars, LL: lateral lip, PS: palp scar). E. Holotype, anterior notopodium. F. Same, close-up of notochaetal regions, left, median and distal. G. Same, neurochaetae from a median chaetiger. H. Same, neurochaetae from a posterior chaetiger. Scale bars: A: 1 mm, B – C: 0.5 mm, D: 0.3 mm, E: 100 µm, F: 10 µm, G: 50 µm, H: 25 µm.

FIGURE 4. Piromis capulata (Moore, 1909) n. comb. A. Holotype (CAS- 19721), complete in lateral view. B. Same, anterior end, lateral view. C. Same, anterior end, dorsal view, notice the eroded areas. D. Non-type specimen (USNM- 40484), anterior end, dorsal view. E. Same, anterior end, palps and most branchiae detached (BS: branchial scars, LL: lateral lip). F. Same, right neuropodium showing the gonopodial lobe with an asterisk in the base. G. Holotype, notochaetal regions, basal, median, distal. H. Same, median neuropodia with an insert showing the tips. Scale bars: A: 5 mm, B: 2.3 mm, C: 1.5 mm, D – E: 2 mm, F: 325 µm, G: 100 µm, H: 50 µm.