Eurysyllis mercuryi Lucas, Martín & Parapar, 2012, sp. nov.
Creators: name: Lucas, Yolanda
name: Martín, Guillermo San
name: Parapar, Julio
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Phyllodocida
Syllidae
Eurysyllis
Eurysyllis mercuryi

description: Eurysyllis mercuryi sp. nov.
Figures 1–4
Type material: A total of 13 specimens were obtained from two DIVA-Artabria I samples. Sample AT-1000, holotype (MNCN 16.01/12026) and 9 paratypes (MNCN 16.01/12030-38); 08/09/2002, 1091– 1132 m, stones and dead corals, 43º57.030’N, 08º54.795’W. Sample AT-800, 3 paratypes, 11/09/2002, 770– 842 m, nodules and stones, 43º47.188’N, 08º53.053’W (MNCN 16.01/12027-29).
Diagnostic characters: Dorsal compound chaetae with elongated blades and strong spinulation on distal part of shafts, especially on anterior chaetigers.
Description based on holotype: Body small, ovate-elongated, dorsoventrally flattened (Fig. 1 A, 3A), slightly bulging from peristomium to posterior proventricular segments, without colour marks, somewhat opaque (preserved material). Holotype, longest specimen, 4.8 mm long, 0.54 mm wide, 55 chaetigers. Dorsum of segments with four spherical tubercles, forming four longitudinal rows (Figs. 1 A, C, 3B); peristomium with only two dorsal tubercles (Figs. 1 A, 3B). Two median rows of tubercles more elevated than those of lateral rows. Prostomium ovate, with two dorso-lateral lobes, translucid, sometimes difficult to see (Figs. 1 A, 3B). Three spherical antennae, similar to dorsal tubercles but slightly larger, inserted on the anterior margin of the prostomium; median antenna slightly longer than lateral ones. Two pairs of large eyes situated laterally on prostomium, close to each other on each side. Palps not visible dorsally, fused all along their length, with median groove forming a bilobed spherical structure (Figs. 1 B, 3C). Peristomium shorter than subsequent segments; dorsal tentacular cirri spherical, similar in size to antennae (Figs. 1 A, 3B); ventral tentacular cirri similar, but distinctly smaller, only visible ventrally (Figs. 1 B, 3C). Nuchal organs as two small ciliated grooves, between prostomium and peristomium (Fig. 3 D, arrow). Segments numerous, short; parapodial dorsal cirri with well-developed, elongated cirrophores; cirrostyles with single article, spherical, small, similar in size and shape to antennae, tentacular cirri and dorsal tubercles. Ventral cirri triangular, with several ventral pores (Fig. 3 E, F, arrows). Parapodia provided with 9–10 compound heterogomph chaetae, with shafts distally spinose, especially in dorsal and anterior chaetae, and less spinose to smooth in more ventral and posterior chaetae (Fig. 2). Blades of anterior chaetae slender, elongated, unidentate, thin, 51–52 μm long dorsally, 35–36 μm long ventrally, with moderately long marginal spines (Figs. 2 A, 4A–C).
Blades of midbody compound chaetae similar in shape, but distinctly shorter (41–42 μm long), with moderately long marginal spines (Figs. 2 C, 4D); those of posterior parapodia shorter, with shorter marginal spines or smooth (Figs. 2 E, 4E, F). Dorsal simple chaeta absent; ventral simple chaeta curved, smooth, unidentate (Fig. 2 F). Single acicula in each parapodium, distally expanded with central thin tip distally (Figs. 2 B, D, G). Pharynx, through about seven segments, with middorsal anterior tooth; trepan not observed (no specimen with everted pharynx). Proventricle elongated, through about 6 segments, with 20–22 muscular cell rows (Fig. 1 A). Pygidium small, with two spherical, anal cirri (Fig. 1 C).
Etymology: The species is named in honour of Freddie Mercury (nickname of Farrokh Bulsara), leader of the rock band Queen.
Type locality: Continental slope off Ártabro Gulf (Galicia, NW Spain); on hard substrates (dead corals and stones), from 1091 to 1132 m deep.
Remarks: Only four species of Eurysyllis are currently known: E. tuberculata Ehlers, 1864, common in NE Atlantic and Mediterranean waters, but also present in Australia (San Martín et al. 2008); E. pacificus (Hartman, 1954) from the Marshall Islands (South Pacific); E. spicum Kudenov & Harris, 1995 from California; and E.
japonicum Imajima, 2003 from Japan. All differ from E. mercuryi sp. nov. in presenting smooth or very slightly spinulated and remarkably shorter chaetae (Hartman 1954; Kudenov & Harris 1995; Imajima 2003; San Martín 2003). Eurysyllis spicum and E. pacificum have straight aciculae, slightly rounded and distally hooked. Eurysyllis tuberculata has aciculae similar to E. mercuryi sp. nov., but distinctly thicker distally. Furthermore, the new species has more separated lateral antennae from the median antenna, a proventricle distinctly longer, with similar number of muscle rows, chaetae markedly longer and spinose (especially on anterior parapodia), and aciculae with longer distal tips as E. tuberculata. The latter is a widely distributed species (N Atlantic, Mediterranean and Australia), found in a wide variety of substrata (dead corals, sand, Posidonia beds, maërl, Amphioxus sand, etc.) and depths (0–760 m) (San Martín 2003; San Martín et al. 2008); and was also found in DIVA-Artabria I samples in the same depths as E. mercuryi sp. nov.
description: Published as part of Lucas, Yolanda, Martín, Guillermo San & Parapar, Julio, 2012, Two new species of Syllidae (Annelida: Polychaeta) from DIVA-Artabria I project (cruise 2002) to deep areas off NW Spain, pp. 77-88 in Zootaxa 3589 on pages 78-83, DOI: 10.5281/zenodo.210484