Fimbriosthenelais longipinnis (Grube 1870)

Sthenelais variabilis.—Horst 1917:111 (part; Siboga station 240)

MATERIAL EXAMINED.—Banda Anchorage, 9–45 meters, Siboga station 240, 22 November–1 December 1899—holotype (ZMA 1387.4).

DESCRIPTION.—Length of holotype (anterior fragment of 46 segments) 20 mm, width, including setae, 5 mm. Wide middorsal ridge on segments 2–5 (Figure 11a). Ventral surface smooth, not papillate. Elytra subreniform, mostly smooth, with microtubercles confined to anterior crescent-shaped areas (Figure 11m) and on medial areas of more posterior elytra (Figure 11n,o), with long papillae along lateral borders and several irregular submarginal rows; microtubercles low, rounded.

Prostomium with median antenna with large auricles on ceratophore and moderately long style; lateral antennae short, subulate; four eyes arranged in square, moderate in size, anterior pair larger than posterior pair, hidden by auricles of median antenna; palps extending about to segment 5; nuchal organs prominent (Figure 11a). Tentacular parapodia with dorsal tentacular cirri shorter than median antenna; ventral tentacular cirri about half as long as dorsal cirri; inner tentacular lobe extending nearly to tip of ventral tentacular cirrus, fused to shorter, rounded inner palpal sheath; dorsal ctenidium elongate-oval (Figure 11a,b).

Parapodia of segments II and III directed anteriorly, slightly modified from following segments (Figure 11a,c–e). All neurosetae compound falcigerous, upper ones with long multiarticulate blades (about 6 articles) and stems with spinous rows; middle ones stouter, with articulate blades (about 4 articles) and stems smooth; lower ones slender, with articulate blades and stems with few spines (Figure 11d). Additional small ctenidia located medial to elytrophores of segment II (Figure 11a).

Parapodia of anterior (Figure 11f–h) and middle regions similar. Cirriform branchiae beginning on segment IV (Figure 11f). Clavate notopodia with few stylodes and fimbriated bracts—few papillae on lower anterior part. Neuropodial acicular lobes with 1–3 oval stylodes. Bilobed posterior bracts fimbriated—papillae longer on upper and lower parts. Anteroventral bracts fimbriated, with row of short papillae. Additional papillae (2–4) on lower sides of neuropodia medial to anteroventral bracts. Blades of C-shaped group of stout neurosetae short to longer, with 1–2 articles, with smooth stems (Figure 11k). Upper anterior group of neurosetae simple spinous (Figure 11i) and compound falcigerous with long articulate blades (about 6 articles); stems with few spines (Figure 11j). Blades of anteroventral slender neurosetae with 2–5 articles; stems smooth or with few spines (Figure 11l). Ventral cirri tapered, with short outer basal knob; usually 2 (2–3) long papillae on medial bases of ventral cirri.

DISTRIBUTION.—Indonesia. In 9 to 45 meters.

Fimbriosthenelais longipinnis (Grube)

Sthenelais longipinnis Grube, 1870:493; 1875:75, 77. Sthenelais variabilis Potts, 1910:349 (part; var. glabra), pl. 19: fig. 22 [not fig. 23], pl. 21: fig. 63—Horst 1917:11 [part; Siboga station 114].—Monro 1939:172 [part; not Cape Verde Islands].

Sthenelais dubiosa Horst, 1917: 111, pl. 22: fig. 7. [?]Sthenelais minor var. digitata Fauvel, 1919:344.

MATERIAL EXAMINED.—Red Sea, Ehrenberg, collector—holotype of Sthenelais longipinnis (ZMB 495).

Maldive Islands, Hulule, Male Atoll, 20 June 1900, J. S. Gardiner, collector—lectotype of Sthenelais variabilis (var.glabra) (BMNH 1924:3:1:105).

Indonesia: Bay of Badjo, west coast of Flores, shore, Siboga station 50, 16/18 April 1899—syntype of Sthenelais dubiosa (ZMA 1388). Kwandang Bay entrance, 0°58.5′N, 122°55′E, 75 meters, very fine hard sand, Siboga station 114, 8 July 1899—1 specimen (ZMA 1387.2; identified by Horst as S. variabilis). Anchorage east of Dangar Besar, Saleh Bay, reef, Siboga station 313, 14/16 February 1900—syntype of S. dubiosa (RMNHL 1195).

Marianas, Lagoon west of Saipan, 4 May 1949, P. E. Cloud, collector—1 specimen (USNM 26096).

TYPE-MATERIAL.—The holotype of Sthenelais longipinnis (ZMB 495) consists of an anterior fragment of 25 segments and a posterior fragment of 56 segments, including a regenerating end of about 13 segments, with a total length of 29 mm and 3 mm in width, including setae. All the elytra are now missing except for a single one loose in the vial (Figure 17a).

The types of Sthenelais variabilis, deposited in the British Museum, consist of three syntypes from the Maldive Islands (BMNH 1924:3:1:105–106). Potts (1910) described two varieties, var. glabra and var. hirsuta, based chiefly on differences in the elytra. The varieties were not clearly indicated on the labels. One of the three syntypes agrees with the var. glabra and is herein selected as the lectotype (BMNH 1924:3:1:105). The other two specimens (BMNH 1924:3:1:106a, b) agree with var. hirsuta and are referred to Fimbriosthenelais hirsuta. The lectotype of S. variabilis var. glabra consists of an anterior fragment of 58 segments, 22 mm long and 4 mm wide, including setae; eggs are present in the body cavity. Some of the elytra show faint color markings.

The two syntypes of Sthenelais dubiosa consist of anterior fragments. One of them (ZMA 1388) has 41 segments and is 22 mm long and 4 mm wide, including setae. The other syntype (RMNHL 1195) has 34 segments, is 13 mm long and 5 mm wide, including setae.

DESCRIPTION.—Length more than 30 mm, width 3 to 5 mm, including setae, segments numerous (more than 80). Wide middorsal ridge on segments 2–5, with 2–4 pairs of small ctenidia alongside (Figure 15a). Ventral surface finely papillate. Elytra thin, transparent, suborbicular, subrectangular to subreniform. Anterior elytra with uniformly distributed microtubercles and lateral borders with papillae: microtubercles low, rounded to subconical (Figures 16h, 17b). More posterior elytra with microtubercles confined to anterior and medial regions, sometimes with few submarginal microtubercles near lateral papillate borders (Figures 16i, 17a,c–e).

Prostomium with median antenna with large auricles on ceratophore and moderately long tapered style; lateral antennae short, subulate; four eyes arranged in square, moderately large, anterior pair much larger than posterior pair; palps extending about to segment 12 (9–16); nuchal organs small (Figure 15a,b). Tentacular parapodium with dorsal tentacular cirri longer than median antenna; ventral tentacular cirrus about half as long as dorsal cirrus; inner tentacular lobe shorter than ventral tentacular cirrus, fused to shorter, rounded inner palpal sheath; dorsal ctenidium elongate-oval (Figure 15a,b).

Parapodia of segments II and III directed anteriorly, slightly modified from following segments; with pair of small ctenidia on lateral lips (Figure 15a–d). All neurosetae compound falcigerous, with articulate blades (3–11 articles), and bifid tips; stems with 3–10 spinous rows; lower neurosetae more slender than middle and upper ones (Figure 15e). Additional small ctenidia located medial to elytrophores of segments II and IV and medial to ventral cirri of segments III–XIII (Figure 15a,d).

Parapodia of anterior (Figure 16a,b) and middle regions similar. Cirriform branchiae beginning on segment VI. Notopodial bracts with row of papillate clavate stylodes on anterior side. Neuropodial acicular lobes with 1–2 papillate clavate stylodes. Upper and lower lobes of bilobed posterior bracts each with few papillate clavate stylodes (1–3). Anteroventral bracts fimbriated. Anterior upper bracts inconspicuous. Blades of C-shaped group of stout neurosetae short to longer, with 1–3 articles; stems smooth or with few spines (Figure 16e). Upper anterior group of neurosetae simple spinous (Figure 16c; not present on more anterior segments) and compound falcigerous with articulate blades (4–7 articles) and stems with 2–7 spinous rows (Figure 16d). Blades of anteroventral slender neurosetae with 2–7 articles; stems with 1–2 spines (Figure 16f). Ventral cirri with small basal knob.

DISTRIBUTION.—Red Sea, Indopacific (Maldives, Zanzibar, Indonesia), Central Pacific (Marianas). Low water to 75 meters.