Fimbriosthenelais zetlandica (McIntosh, 1876)

Barnich, Ruth & Haaren, Ton Van, 2021, Revision of Sthenelais Kinberg, 1856, Fimbriosthenelais Pettibone, 1971 and Eusthenelais McIntosh, 1876 (Polychaeta, Sigalionidae) in the Northeast Atlantic, European Journal of Taxonomy 740, pp. 138-171 : 155-158

Fimbriosthenelais zetlandica (McIntosh, 1876) (emended)

Figs 5F , 6

Sthenelais ? zetlandica McIntosh, 1876a: 390 , pl. 70 figs 15–17.

Sthenelais atlantica McIntosh, 1876b: 405 , pl. 72 figs 16–17.

Sthenelais Sarsi McIntosh, 1897b: 174 , pl. 3 figs 1–5 (description sufficient; see also Pettibone 1971). Sthenelais papillosa Day, 1960: 289 , fig. 3e–j.

Sthenelais vachoni Rullier, 1964: 139 , fig. 6.

Sthenelais zetlandica – McIntosh 1900: 414, pl. 30 fig. 14, pl. 34 fig.7, pl. 41 figs 24–26. — Chambers 1985: 26, fig. 20a–b. — Chambers & Muir 1997: 160, fig. 52.

Fimbriosthenelais zetlandica – Pettibone 1971: 32, figs 21–22. — Barnich & Fiege 2003: 119, fig. 60. — Gil 2011: 941. — Núñez et al. 2015: 223, fig. 90.

Diagnosis

Dorsal cirri absent on segment 3. Ventral body surface densely papillated. Outer and posterior elytral margin with numerous short papillae, elytral surface covered by rounded to conical microtubercles. Parapodial stylodes distinctly papillated. Neuropodial posterior bracts truncate.

Type material

The holotypes of Sthenelais ? zetlandica and Sthenelais atlantica were investigated by Pettibone (1971) and Chambers (1985); all others by Pettibone (1971), except for Sthenelais sarsi (type material probably lost).

The respective type localities are: Sthenelais ? zetlandica ( United Kingdom, Shetland Islands, NE Atlantic), Sthenelais atlantica ( United Kingdom, NE Atlantic), Sthenelais Sarsi ( Norway, Hardanger Fjord, NE Atlantic), Sthenelais papillosa ( South Africa, False Bay, Southeast Atlantic), Sthenelais vachoni ( Cape Verde Islands, NE Atlantic).

Other material (examined)

FRANCE • 4 specs; W Mediterranean Sea , Cortiou; stn D1; 1976; EtOH preserved; ex Coll. Bellan; SMF 12682. ( Fig. 6C, F–H )

IRELAND • 1 spec.; Irish Sea Benthos ; stn ISB05b; 30 Jul. 2006; EtOH preserved; TUM 39480. ( Fig. 6A–B, D–E )

UNITED KINGDOM • 1 spec.; S England , E English Channel ; stn 92a; 22 Aug. 2005; EtOH preserved; TUM 36747 ( Fig. 5F ) • 1 spec.; S England , E English Channel; stn 166a; 22 Aug. 2005; EtOH preserved; TUM 37011 • 4 specs; S England , E English Channel; stn 217a; 22 Aug. 2005; EtOH preserved; TUM 36765 .

Further Mediterranean material, see Barnich & Fiege (2003).

Description

PROSTOMIUM. Median antenna with short, smooth, tapering style; ceratophore with small auricles. Lateral antennae fused to inner dorsal side of tentaculophores, very short, not reaching half the length of dorsal tentacular cirri. Two pairs of eyes present ( Fig. 6A ).

TENTACULOPHORES. Dorsal tentacular cirri subequal or slightly longer than median antenna, of similar shape. Ventral tentacular cirri about half the length of dorsal ones ( Fig. 6A ).

ELYTRA. With short, clavate papillae on outer lateral and posterior margin; surface covered by rounded to conical microtubercles ( Fig. 6B–C ).

CIRRI. Dorsal cirri absent from segment 3. Ventral cirri with basal knob and distal article, without long basal papillae ( Fig. 6D–E ).

PARAPODIA. Stylodes club-shaped or cylindrical, with large, obvious papillae ( Fig. 5F ). Parapodia of anterior and middle body with stylodes present on anterior side of notopodial bract, on neuropodial acicular lobe, on truncate posterior neuropodial bract, and on neuropodial anterodorsal and anteroventral bracts ( Fig. 6D–E ).

CHAETAE. Notochaetae slender, spinous, tapering to simple capillary tip. All neurochaetae compound falcigers with bidentate tip. Those of anteriormost segments slender with multi-articled blades. In all other parapodia falcigers of similar size and shape with bi- or three-articled blades. Middle neurochaetae slightly stouter than those of upper and lower groups ( Fig. 6F–H ).

BODY SURFACE. Densely papillated ventrally.

SIZE. Length more than 40 mm, width up to 4 mm for more than 100 segments. Specimens figured: TUM 36747 ( Fig. 5F ): anterior fragment, width 4 mm; TUM 39480 ( Fig. 6A–B, D–E ): complete specimen, length 54 mm, width 3.5 mm for 120 segments; SMF 12682 ( Fig. 6C, F–H ): anterior fragment, width 4 mm.

Remarks

The description above is emended for the details regarding shape and size of the stylodes and their associated papillae and for the terminology used in the description of the neuropodial bracts.

Distribution and habitat

Reported from the NE and Southeast Atlantic and the Mediterranean Sea. Also reported from the Gulf of Oman, Indian Ocean. Occurring on muddy substrates from 30 to 560 m depth (see Pettibone 1971; Barnich & Fiege 2003; Wehe 2007).

Figures

Fig. 5. Comparison of stylodes. A–D. Sthenelais boa (Johnston, 1833), TUM 39683. A. Large specimen, width 6 mm, segment 21. B. Same, segment 4. C. Medium specimen, width 4 mm, segment 21. D. Small specimen, width 3 mm, segment 21. E. Fimbriosthenelais longipinnis (Grube, 1869), SMF 24345, width 2.5 mm, segment from mid-body. F. Fimbriosthenelais zetlandica (McIntosh, 1876), TUM 36747, width 4 mm, segment 20. Scale bar: 50 µm.

Fig. 6. Fimbriosthenelais zetlandica (McIntosh, 1876). TUM 39480 (A–B, D–E) and SMF 12682 (C, F–H). A. Anterior end, palps not figured, bent downwards. B. Right elytron of segment 5. C. Detail of posterior elytral margin. D. Left parapodium of segment 13, anterior view. E. Same, posterior view. F–H. Neurochaetae of segment 11, all distal part. F. Upper compound falciger. G. Middle compound falciger. H. Lower compound falciger. Scale bars: A, D–E =500 µm; B =1 mm; C, F–H=100 µm.