Synallactes cf. challengeri ( Théel, 1886 ), Theel, 1886

Thandar, Ahmed S. & Rambaran, Ryan, 2015, On some sea cucumbers (Echinodermata: Holothuroidea) from off the south and west coasts of South Africa collected by the South African Environmental and Observation Network (SAEON), Zootaxa 3999 (1), pp. 41-61 : 46-49

Synallactes cf. challengeri ( Théel, 1886)

( Table 1, Figures 4 & 5 )

Stichopus challengeri Théel, 1886: 163 -164, pl. 10, fig. 21; Ludwig, 1889: 331; Edwards, 1907: 65 –66, fig. 12. Synallactes challengeri ; Östergren, 1896; Ludwig, 1898: 8; Clark, 1922: 46 (list); Massin, 1992: 313 –316, figs. 2–3 (synonymy); Branch et al., 1993: 55 (in key).

Diagnosis (see Théel 1886, Massin 1992).

Material examined. A32145, off Lamberts Bay, Demersal West Coast Trawl V279, 32 ° 19.41'S, 16° 19.40'E, Demersal Trawl 007-6172, Cruise 279, 633 m, 11/01/2012, Lara Atkinson, 3 specs.

Description. Body elongate, form sub-cylindrical, slightly flattened, flaccid. Length up to 221 mm, width in mid-body 24 mm in preservative. Skin thick, soft, smooth. Mouth ventral, anus terminal. Preserved colouration deep purple with some regions off-white. Tentacles 20, peltate, off-white to yellow, densely packed in two circles, reduced tentacles in inner circle. Tube feet restricted to ventral surface, length 3–15 mm, slender, cylindrical, more or less confined to ambulacra with a few in inter-ambulacral regions, ventro-laterally in 2–3 rows, mid-ventrally in two paired rows, coalesced and densely packed posteriorly, extending to mouth and anus. Papillae in six rows, varying in length, often highly reduced (2–14 mm), longer at extremities of body. Tube feet and papillae surround both mouth and anus ventrally and dorsally. Anal teeth absent.

Specimen 1—eviscerated, only calcareous ring and Polian vesicle present, other structures lost; length 57 mm. Plates of calcareous ring fused, notched posteriorly, radial plates larger, undulating anteriorly, deeply notched posteriorly; inter-radial plates with triangular anterior projection. Polian vesicle single, large (35 mm), saccular. Longitudinal muscles unpaired, broad.

Specimen 2—length 87mm; calcareous ring and longitudinal muscles identical to those of specimen 1. Stone canal and madreporite not observed. Polian vesicles three, saccular, two large (12 mm, 14 mm) and one very reduced (5 mm). Only one respiratory tree present, 35 mm long, well developed. Gonad elongate, unbranched, full of eggs.

Body wall ossicles as cruciform bodies (pseudo-tables) of variable size (disc diam. 64–243 µm) with tri-radiate disc, with each arm usually dichotomously branched or bifurcate or anastomosing terminally, forming one or more perforations, but rarely a complete disc, but never lattice-like; spire (pseudo-spire) (34–84 µm), with or without terminal hole but sometimes terminally bifurcate. Tube feet with large rods, small and large cruciform bodies and end-plates. Large rods of variable form and size (354–738 µm), curved or straight, spinous or smooth, slender or bulky, perforated at one or both ends or without perforations, sometimes terminally forked, sometimes with third arm, with or without perforations. Small cruciform bodies (37–75 µm) with three, usually branched arms with bifurcate, non-perforate ends; spire short (19–53 µm), with or without terminal hole and teeth. Large cruciform bodies (100–150 µm) with three arms, with or without terminal hole, pillars nearly half length of arms (47–59 µm), also with or without terminal hole. End-plates large (232–261 µm), multilocular, with irregular margin. Papillae also with similar cruciform bodies (crosses) - small crosses (disc diam. 88–137 µm; pillar height 44–142 µm); large crosses (disc diam. 222–434 µm; spire height 64–197 µm). Papillae rods of variable size (310–621 µm) and form, usually with smooth margin and one end with multiple perforations. Rods with spinous margin, side projections and both extremities with or without perforations. Anal region predominantly with large cruciform bodies (disc diam. 128–424 µm, spire height 54–113 µm) with three dichotomously branched arms with terminal perforations, arms sometimes anastomosing, forming an almost complete disc. Tentacles comprise small and large rods; small rods (97–153 µm), usually with smooth margins or adorned with a few spines, extremities sometimes bifurcate, with or without teeth; large rods (197–714 µm) with spinous margins, sometimes with side projections with or without teeth, extremities non-perforate or perforated at one or both ends.

Théel Massin Current collection 1886 1992

Distribution Antarctic region (46° Sub-Antarctic (Marion and West coast of South 53'S, 51° 52'E) Prince Edward Islands) Africa (32° 19'S, 16° 19'E)

Body wall cruciform bodies 3–4 armed, disc diam. 56 3–4 armed, disc diam. 35–100 3- armed only, disc diam.

deposits Μm, spire height 80 Μm Μm, spire height 40–50 Μm 63–243 Μm, spire height

34–84 Μm

Tube feet rods not recorded 220–660 Μm 354–738 Μm

cruciform bodies disc diam. 60–100 Μm small ones with disc

diam. 37–75 Μm; large ones 100–150 Μm diam.

end-plates can reach 1 mm in diam. 232–261 Μm

Papillae cruciform bodies disc diam. 280 Μm disc diam. 20–350 Μm small 37–75 Μm disc diam.; large 100–150 Μm disc diam.

Tentacles rods not recorded. 60–800 Μm small 97–153 Μm, large

197–714 Μm Distribution (After Solis-Marin 2003, extended herein). Off Crozet, Marion and Prince Edward Islands, off southern Australia, in the north Pacific from Alaska (Uyak Bay and Kodiak Island) and now possibly the west coast of South Africa, 20–1115 m.

Remarks. According to Massin (1992) S. challengeri is known to be restricted to the Sub-Antarctic waters. However, Edwards (1907) recorded this species from Alaska but this record needs verification (Solis-Marin 2003). The species has also been reported from southern Australia ( Solis Marin 2003).

The specimens in the current collection strongly resemble S. challengeri , as described by Théel (1886) and redescribed by Massin (1992) from both the type and new materials, but with some variations. Table 1 compares the three samples. Both authors describe the skin as thin, whereas the current specimens all have thick skins but this may be due to their greater degree of contraction. Specimens from all collections indicate that S. challengeri has a variable size range (69 mm to more than 160 mm). Théel (1886) mentions that the papillae are scattered across the ambulacral and inter-ambulacral regions, with the arrangement in rows being obvious only dorso-laterally. However, specimens examined by Massin (1992) and those in the current collection, display papillae in six distinct longitudinal rows. The number of tentacles in Théel’s specimens (19) also differs from specimens examined by Massin and in the current collection (20) but such an oddity is quite common amongst holothuroids. Similarly, the presence of a branched gonad described by Théel was not apparent in one of the specimens in which the gonad was identified. The number and size of Polian vesicles are also variable in all collections.

Four- armed cruciform bodies were not observed in the current material. However, the form of the ossicles from the tube feet, papillae and tentacles correspond well with other descriptions but their size vary across collections (see Table 3 ). The diameter of the cruciform bodies of the body wall was larger in the current collection. The end-plates recorded by Massin (1992) are massive when compared to those in the current collection. Cruciform bodies and tentacle rods in the current collection were divided into two size-groups: small and large. The cruciform bodies of the papillae examined by both Théel and Massin appear to have a much higher upper size limit than those in the current collection. The tentacle rods in Massin’s material also have a greater size variation than those of the current collection. However, both Théel (1886) and Massin (1992) did not differentiate the cruciform bodies of the tube feet and tentacle rods on size. Hence, the southern African material is only tentatively referred to S. challengeri as it may prove to be another species or one that is new to science. The differences may eventually prove to be only geographic variations in a distantly distributed population.

It must here be noted that some west coast species, especially those from the Namibian –Angolan region do have Antarctic affinities (eg. the ascidian fauna, see Primo & Vázquez 2004). Therefore, it is possible for the above Subantarctic species to also occur in the cold waters of the southern African west coast.

Figures

FIGURE 4. Synallactes cf. challenger i (Theel, 1886). A 32145 A. Body wall tables; B. part of tube feet end plate; C. Rods from tube feet; D. Papillae ossicles; E. Tables from anal region; F. Cruciform bodies from tube feet; G. Large and small tentacle rods. H. Calcareous ring. (Figures A – E, G, scale b; Figure F, scale a; Figure H, scale c)

FIGURE 5. Synallactes cf. challenger i (Theel, 1886). A 32145. A. End plate; B and C. Tables of body wall; D. Crosses of body wall; E. Partially complete disc; F. Table from anal region; G. Tentacle rods; H. Tube feet rods: I. Entire specimen.