Piromis fauchaldi, 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 : 18-19

Piromis fauchaldi n. sp.

Figure 6

Type material. Eastern Pacific Ocean, Gulf of California. Holotype (LACM-AHF -2511), Agua Verde Bay, Baja California Sur, Knudsen Sta. 127 (25°31ʹ24ʺ N, 111°03ʹ56ʺ W), 98 feet (31.6 m), green mud, shells, 25 Jan. 1955, Knudsen, coll. One paratype (LACM-AHF-2512), anterior fragment, damaged, previously dissected, R/V Velero III, Sta. 751 (23°22ʹ45ʺ N, 109°24ʹ15ʺ W), off Los Frailes, Baja California Sur, 5–15 fathoms, sand, algae, 4 Apr. 1937. One paratype (LACM-AHF-2513), anterior fragment, damaged, R/V Velero II I, Sta. 1733 (23°24ʹ0 7ʺ N, 109°24ʹ15ʺ W 23°23ʹ50ʺ N, 109°24ʹ30ʺ W), 3.7 km SE off Cabo Pulmo, Baja California Sur, 21 fathoms, 13 Mar. 1949.

Description. Holotype complete, broken into two parts, previously dissected anteriorly, many chaetae broken ( Fig. 6 A); tunic papillated, with large adhering sediment particles, especially dorsally ( Fig. 6 B); papillae in two longitudinal rows dorsally, four rows ventrally; each papilla cirriform, capitate. Holotype 25(11+14) mm long, 1.8 mm wide, cephalic cage 2.8 mm long, 75(28+47) chaetigers.

Anterior end observed by dissecting holotype. Cephalic hood short, marginal papillae not visible. Prostomium short, four eyes, fused, directed fronto- and posterolaterally. Caruncle pale, well-developed, separating branchial lobes, extending almost to branchial plate split ( Fig. 6 D). Palps pale, palp keels rounded, short. Branchiae cirriform, arising on tongue-like protuberance, distally cleft, each filament with irregular dark bands along their length, about 60 filaments per side. Palps as long as largest branchiae. Dorsal and ventral lips reduced, lateral lips wide, better developed. Nephridial lobes not seen.

Cephalic cage chaetae damaged, about 1/9 body length, or 1.5 times longer than body width. Chaetigers 1–2 involved in cephalic cage; chaetae arranged in short rows, lateral and ventrolateral fascicles; each with 2–3 noto- and 3–4 neurochaetae per bundle. Anterior dorsal margin of chaetiger 1 with median lobe, projecting anteriorly, bent ventrally, with four or five distal papillae; anterior chaetigers with long papillae, chaetigers 2–3 with dorsal papillae making short, conical notopodial lobes directed forward. Chaetigers 1–3 of similar length. Chaetal transition from cephalic cage to body chaetae abrupt; chaetiger 4 with thin multiarticulate neurohooks, one with bidentate tip. Chaetigers 3–7 with ventrolateral groups of 3–5 short papillae. Gonopodial lobes not seen.

Parapodia well developed, especially in anterior chaetigers; parapodia lateral, median neuropodia ventrolateral. Notopodia with one pre- and three postchaetal papillae, each cirriform, capitate, longer by chaetigers 11–15, each about 1/3–1/2 as long as notochaetae. Neuropodia with one pre- and 1–2 postchaetal papillae, smaller than notopodial ones.

Median notochaetae arranged in short oblique row, five notochaetae per bundle, about half as long as body width; all notochaetae multiarticulated capillaries, each with basal articles short, medial and distal ones long, becoming shorter towards tip ( Fig. 6 E). Neurochaetae multiarticulated capillaries in chaetigers 1–3, chaetiger 4 with single hooked tip, entire, from chaetiger 5 all neurochaetae bifid multiarticulated hooks, arranged in transverse row ( Fig. 6 F), 4–5 hooks per ramus in following chaetigers ( Fig 6 G), many broken. Neurohooks with 11–12 articles, all long throughout the chaetae but 1–2 median ones slightly longer, decreasing in size distally; distal article slightly falcate, tapering, bidentate.

Posterior region tapering, without sediment particles, pygidium with dorso-terminal anus, without anal cirri.

Etymology. This species is being named after Kristian Fauchald, good friend and better mentor, in recognition of his many contributions to polychaete taxonomy, because he noticed that these specimens belong to an undescribed species, and especially to acknowledge his encouraging, unrestricted, and long-term support for my studies on the group.

Type locality. Agua Verde Bay, Baja California Sur.

Variation. The two paratypes were anterior fragments, one (LACM-AHF-2512) was 17 mm long, 2.5 mm wide, cephalic cage broken, 3 mm long, 42 chaetigers, whereas the other (LACM-AHF-2513) was 25 mm long, 4 mm wide, cephalic cage 7 mm long, 23 chaetigers.

Remarks. Piromis fauchaldi n. sp. is closely allied with P. robertsi ( Hartman, 1951) from the Gulf of Mexico. Both species have large sediment particles covering the body; however, they differ in the relative number of notochaetae, development of the ventrolateral tubercles in chaetiger 1, and on the number of articles in neurohooks of posterior chaetigers. Thus, P. fauchaldi n. sp. has only five notochaetae while P. robertsi has up to eight per bundle; ventrolateral tubercles are present in P. robertsi , while in P. fauchaldi n. sp. they are modified into a group of 3–5 papillae along the first five chaetigers, but they are not grouped into a tubercle either individually or collectively, and the neurohooks in P. fauchaldi n. sp. have more articles (10–12) than in P. robertsi (3–7).

Distribution. Southwestern Gulf of California, in muddy, sandy or mixed bottoms, in 10–40 m depth.

Figures

FIGURE 6. Piromis fauchaldi n. sp. A. Holotype (LACM- 2511), complete. B. Same, anterior end, dorsal view. C. Paratype (LACM-AHF 1733), anterior end, ventral view showing some epizoic hydroids. D. Holotype, head, palps and branchiae removed (BS: branchial scars, Ca: caruncle, Pr: prostomium, PS: palp scar). E. Paratype (LACM-AHF- 2512), notochaetae from an anterior chaetiger showing basal, median and distal regions. F. Same, neurochaetae from a median chaetiger, insert showing chaetal tips. G. Same, neurochaetae from a posterior chaetiger, insert showing chaetal tips. Scale bars: A: 2 mm, B – C: 1 mm, D: 250 µm, E: 50 µm, F: 75 µm, G: 100 µm.