Comprehensive Description

provided by Smithsonian Contributions to Zoology
Fimbriosthenelais zetlandica (McIntosh)

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

Sthenelais atlantica McIntosh, 1876b:405, pl. 72, figs. 16, 17; 1900:415, pl. 29: fig. 2, pl. 34: fig. 8, pl. 41: figs, 27, 28.

Sthenelais sarsi McIntosh, 1897:174, pl. 3: figs. 1–5.

Sthenelais zetlandica.—McIntosh 1900:414, pl. 30: fig. 14, pl. 34: fig. 7, pl. 41: figs. 24–26.—Southern 1914:55, pl. 6: fig. 13A,B.—Eliason 1962:228.

Sthenelais papillosa Day, 1960:289, fig. 3e-j; 1967:108, fig. 1.20.a-e.

Sthenelais vachoni Rullier, 1961:139, fig. 6,A–L.

MATERIAL EXAMINED.—North Atlantic off Shetland Island, dredged, 1867, G. Jeffreys, collector—holotype of Sthenelais? zetlandica (BMNH 1921:5:1:593). North Atlantic off Great Britain, 558 meters, Porcupine station 2, 1870—holotype of Sthenelais atlantica (BMNH 1921:5:1:594).

Cape Verde Islands off Northwest Africa, 15° 16′30″N, 23°47′35″W, 50–65 meters, shelly bottom, Calypso station 26, 18 November 1959—holotype of Sthenelais vachoni (MNHNP).

False Bay, South Africa, 34°13.3′S, 18°31′E, 39 meters, sand, FAL station 444E—1 specimen (J. H. Day collection).

TYPE-MATERIAL.—The holotype of Sthenelais? zetlandica consists of an anterior fragment of 20 segments lacking a head end (segments 12–31, judged by the arrangement of the elytrophores and dorsal tubercles), 9 mm in length and 4 mm in width, including setae.

The holotype of Sthenelais atlantica consists of an anterior fragment of 29 segments, 8 mm in length, and 3 mm in width, including setae. It is in poor shape.

The holotype of Sthenelais vachoni is a complete specimen of about 95 segments, 22 mm in length, and 2 mm in width, including setae.

The specimen of Sthenelais papillosa, collected near the type-locality in False Bay, South Africa, consists of an anterior fragment of 45 segments, 15 mm in length and 3 mm in width, including setae.

DESCRIPTION.—Length more than 40 mm, width 2 to 4 mm, including setae, segments numerous (more than 100). Wide middorsal ridge on segments 2–5 rather indistinct, with 2 pairs of small ctenidia alongside (Figure 21a). Ventral surface thickly papillate with small globular papillae (Figure 22a,b). Elytra delicate, transparent, suborbicular, subrectangular to subreniform, nearly covered with flat to subconical microtubercles, being very lightly chitinized especially on posterior parts of elytra and appearing somewhat areolate; lateral and posterior margins with short clavate to globular micropapillae with minute sensory hairs on tips (Figures 21i,j; 22f).

Prostomium with median antenna with rather small auricles and short tapered style; lateral antennae short, subulate; four subequal, comparatively large eyes arranged in square in middle of prostomium; palps extending about to segment 8 (5–9); nuchal organs inconspicuous (Figure 21a). Tentacular parapodia with dorsal tentacular cirri subequal to or slightly longer than median antenna; ventral tentacular cirri about half as long as dorsal cirri; inner tentacular lobes shorter than ventral tentacular cirri, fused to shorter, rounded inner palpal sheaths; dorsal ctenidia elongate-oval (Figure 21a).

Parapodia of segments II and III directed anteriorly, slightly modified from following segments, with pair of small ctenidia on lateral lips (Figure 21b,c). All neurosetae compound falcigerous; blades with 2–9 articles and bifid tips; stems with 2–4 spinous rows (Figure 21d). Additional small ctenidia located medial to elytrophores of segment II, lateral to bases of ventral buccal cirri (II), and medial to ventral cirri of segments III–VIII (Figure 21a–c).

Parapodia of anterior (Figures 21e,f; 22a,b) and middle regions similar. Cirriform branchiae beginning on segment IV. Notopodial bracts with row of papillate clavate stylodes on anterior side. Neuropodial acicular lobes with 2–3 papillate clavate stylodes. Truncate posterior bracts with row of papillate clavate stylodes. Anteroventral and anterior upper bracts fimbriated—with rows of papillate stylodes. All neurosetae compound falcigerous with bidentate tips, similar in size and shape. Blades of C-shaped group of slightly stouter neurosetae with 2 articles (single article in more posterior neuropodia); stems with 2–4 faint spinous rows (Figures 21g, 22d). Blades of upper anterior group of neurosetae with 2–3 articles; stems with 3–5 spinous rows (Figure 22c). Blades of anteroventral slender neurosetae with 2–3 articles; stems with 2–3 spinous rows (Figures 21h, 22e). Ventral cirri with very small or inconspicuous basal knobs.

DISTRIBUTION.—North and South Atlantic—off Norway, Skagerrak, Shetland Islands, Great Britain, Isle of Man, Northwest Africa (Cape Verde Islands) and South Africa (False Bay). In 33 to 558 meters.

Fimbriosthenelais minor (Pruvot and Racovitza), new combination

Sthenelais minor Pruvot and Racovitza, 1895:465, pl. 20: figs. 111–121.—Fauvel 1923:122, fig. 41 m–q.

Sthenelais minor?—Saint-Joseph 1899:171.

[Not?] Sthenelais minor var. digitata Fauvel, 1919:344. [?=F. longipinnis].

MATERIAL EXAMINED.—Brest, France, collection of M. le Baron de Saint-Joseph, No. 20, 1911–1 specimen (MNHNP).

DESCRIPTION.—Length up to 45 mm, width 3–4 mm, including setae, segments numerous (up to 140). Wide middorsal ridge on segments 2–5, with four pairs of small ctenidia alongside (Figure 23a). Ventral surface smooth, not papillate. Elytra thin, transparent, suborbicular, subrectangular to subreniform, with uniformly distributed microtubercles and lateral borders with long papillae and tactile micropapillae; microtubercles low, rounded to subconical; surface characteristically covered with scattered foreign material, including sand grains and debris (Figure 23k–m).

Prostomium with median antenna with moderately large auricles on ceratophore and moderately long tapered style; lateral antennae short, subulate; four eyes arranged in square, moderately large, anterior pair larger than posterior pair; palps extending about to segment 9; nuchal organs inconspicuous (Figure 23a). Tentacular parapodia with dorsal tentacular cirri subequal to or slightly shorter than median antenna; ventral tentacular cirri about half as long as dorsal cirri; inner tentacular lobes shorter than ventral tentacular cirri, fused to shorter, rounded inner palpal sheaths; dorsal ctenidia elongate-oval (Figure 23a).

Parapodia of segments II and III directed anteriorly, slightly modified from following segments; with pair of small ctenidia on lateral lips (Figure 23a–c). All neurosetae compound falcigerous; blades with 2–8 articles and bifid tips; stems with 3–15 spinous rows (Figure 23d). Additional small ctenidia located medial to elytrophores of segments II and IV and medial to ventral cirri of segments III–VII (Figure 23a).

Parapodia of anterior (Figure 23e,f) and middle regions similar. Cirriform branchiae beginning on segment IV. Notopodial bracts with row of papillate clavate stylodes on anterior side. Neuropodial acicular lobes with 1–2 papillate clavate stylodes. Upper part of bilobed posterior bracts rounded; lower part subtriangular, sometimes terminating in single papillate stylode. Anteroventral bracts fimbriated. Anterior upper bracts inconspicuous. Blades of C-shaped group of stout neurosetae short to longer, with 1 article; stems with faint spinous rows (Figure 23i). Blades of upper anterior group of neurosetae with 2–3 articles; stems with 5–8 spinous rows (Figure 23h); 1–2 simple spinous neurosetae present or absent (Figure 23g; present in some of parapodia of specimen examined and noted by Saint-Joseph; not observed by Pruvot and Racovitza). Blades of anteroventral slender neurosetae with 1–3 articles; stems with 3 spinous rows (Figure 23j). Ventral cirri with small basal knobs.

DISTRIBUTION.—English Channel, France, Mediterranean.
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bibliographic citation
Pettibone, Marian H. 1971. "Partial revision of the genus Sthenelais Kinberg (Polychaeta: Sigalionidae) with diagnoses of two new genera." Smithsonian Contributions to Zoology. 1-40. https://doi.org/10.5479/si.00810282.109