Piromis brisegnoi Salazar-Vallejo, 2011, n. sp.

Piromis brisegnoi n. sp.

Figure 3

Type material. Eastern Pacific Ocean, Gulf of California. Holotype (LACM-AHF -2509), Puerto Refugio (29°33ʹ30ʺ N, 113°32ʹ58ʺ W), Isla Angel de la Guarda, Baja California, 2 Apr. 1940, E.F. Ricketts coll. Two paratypes (ECOSUR, MNHN), Playa Las Moradas, Bahia de Los Angeles, Baja California, rocky intertidal, under rocks, 25 May 1986, SISV coll.

Additional material. Eastern Pacific Ocean, Gulf of California. One specimen (ECOSUR-8/1987), Playa El Caimancito, Bahia de La Paz, Baja California Sur, under stones, 1.5 m depth, 6 Aug. 1987, SISV, coll. (anterior end exposed).

Description. Holotype (LACM-AHF-2509) complete; body pale, chaetae long, abundant, with few sediment particles (Fig. 3 A); anterior region bent over on ventral side; tunic heavily papillose (Fig. 3 B). Papillae not arranged in longitudinal rows, irregularly distributed. Holotype 27 mm long, 4 mm wide, cephalic cage 5.5 mm long, 48 chaetigers.

Cephalic hood not exposed. Upon dissection, prostomium short, with dark pigment in a laterally fading median longitudinal band; anterior eyes black, posterior ones brown. Caruncle well developed, extending to tip of branchial plate (Fig. 3 C), median keel pale, lateral ridges black. Palps contracted; palp keels rounded, elevated, black. Lips distorted by dissection, finely spotted. Branchiae cirriform, arising on tongue-like protuberance, in two lateral groups, each with branchiae arranged in about 30 oblique rows, basal ones with more filaments, each group with about 100 filaments. Nephridial lobes not seen.

Cephalic cage chaetae about 1/5 as long as body length, 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 ten notochaetae per bundle, six thicker, four thinner; parapodia 2–3 with six thick notochaetae, six neurochaetae per bundle.

Anterior dorsal margin of chaetiger 1 with multifid lobe, projected ventrally. Anterior chaetigers with long papillae, chaetigers 2–8 with elevated notopodial lobe. Chaetigers 1–3 of the same length. Chaetal transition from anterior cephalic cage segments to body segments abrupt with multiarticulate bidentate neurohooks from chaetiger 6. Gonopodial lobes not seen.

Parapodia well developed, dorsal lobes in anterior chaetigers (1–8). Parapodia lateral, median neuropodia ventrolateral. Noto- and neuropodia with long chaetal lobes and long digitate papillae; both with 4–5 smaller prechaetal and 4–5 larger postchaetal papillae.

Median notochaetae arranged in transverse ∪-shaped row, with 9–10 chaetae per bundle, each notochaeta half as long as body width, as thick as, or thicker than, neurochaetae; all notochaetae multiarticulated capillaries with short articles basally and medially, markedly longer distally (Fig. 3 D), tips entire. Neurochaetae multiarticulated capillaries in chaetigers 1–5; multiarticulated bidentate hooks from chaetiger 6, arranged in transverse row in chaetigers 1–11, from chaetiger 12 in a J-shaped pattern with 8–9 neurohooks in anterior and median chaetigers (Fig. 3 E), increasing to 12 in posterior chaetigers (Fig. 3 F). Each neurohook with short articles basally, then fewer articles, becoming progressively shorter, with very long distal article. Tips of neurohooks curved, bidentate, accessory tooth not longer than the fang.

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

Etymology. This species is named after my Invertebrate Zoology teacher, Carlos H. Briseño, in recognition of his encouraging lectures and lab sessions, and his unexpected inspirational effect by telling me that studying polychaetes was a very difficult task that I should avoid, and to thank him for his confidence and support by providing lab space and equipment during my early academic career. The last name root has been modified for euphonic purposes.

Type locality. Puerto Refugio, Baja California, Gulf of California.

Variation. Paratypes 32–45 mm long, 5.0 mm wide, cephalic cage 6.0– 6.5 mm long, 42–49 chaetigers.

Remarks. Because of the relative scarcity of sediment particles on the body, Piromis brisegnoi n. sp. is closely allied with P. amoureuxi n. sp., a Caribbean Sea species. The two species differ especially in chaetal features: P. brisegnoi n. sp. has longer notochaetae (about 1/2 as long vs 1/3 as long as body width), and more abundant notochaetae (about 10 vs 6–7 per bundle); the distal neurochaetal article in P. brisegnoi n. sp. is falcate and tapering, while it is straight and of about the same width in P. amoureuxi n. sp.

Distribution. Western coast of the Gulf of California, in intertidal to shallow water, mixed rocky bottoms.