Sclerothyone velligera ( Ludwig and Heding, 1935 )

Thandar, Ahmed S., 2006, New species and new records of dendrochirotid and dactylochirotid holothuroids (Echinodermata: Holothuroidea) from off the east coast of South Africa, Zootaxa 1245, pp. 1-51 : 17-19

Sclerothyone velligera ( Ludwig and Heding, 1935)

Figure 5

Cucumaria ? velligera Ludwig and Heding, 1935: 70, text fig. 49. Pentamera velligera Deichmann, 1948: 351 .

Neothyone ? velligera Panning, 1949: 458 .

Sclerothyone velligera Thandar, 1989c: 295 , figs. 3 & 9b.

Type

?Bonn, Germany.

Type locality

Cape Point, South Africa.

Previous southern African records West coast of Cape Peninsula.

Material examined

SAM­A27902, Off East London, Eastern Cape Province, 32 28.6’ S, 28 58.8’ E, R.V. ‘Meiring Naude’, St. SM 226, 24.vi.1979, 710– 775 m., 1 spec. (male).

Description

Specimen tiny but an almost mature male; form cucumber­like with an extended tentacle crown. Length, including tentacle crown, 6 mm, tentacle crown 2 mm, breadth in mid­body 2 mm. Colour, in alcohol, a dull beige­grey. Anal papillae five, teeth­like, densely packed with spicules but not itself calcified. Tentacles 10, bushy, well­developed, mid­ventral two reduced. Podia non­retractile, restricted to ambulacra in 2–3 rows, well developed, giving impression of being crowded, especially on the dorsal surface; suckers well developed, diameter larger than diameter of podium.

Calcareous ring ( Figure 5 H) well developed, non­tubular, compact, radial and interradial plates only connected to each other at their bases, radial plates anteriorly notched and bearing paired, faintly subdivided posterior prolongations, twice as long as radial plates; interradial plates triangular. Polian vesicle single, anteriorly directed; stone canal very short, free; madreporite ( Figure 5 H) minute, not well calcified. Gonadal tubules unbranched, full of spermatozoa. Respiratory trees poorly developed with sacciform endbranches at their base.

Spicules of body wall comprise tables ( Figure 5 A) of two types: commonly those with oval discs (65–106 µm, mean 87 µm), with four large central holes and a two­pillared spire (27–39 µm, mean 32 µm), terminating in a single point or with three or more teeth; others with larger, more robust, rectangular to sub­rectangular discs (79–88 µm, mean 85 µm), with 4–6 holes and bearing either an arched spire (ca 25 µm) or a two­pillared spire terminating in several teeth. No handle to body wall tables. Podia supported by twopillared, toothed tables ( Figure 5 B) with a curved disc (67–110 µm, mean 88 µm) and a short spire (23–29 µm, mean 27 µm) as well as by curved, multilocular plates/rods (60–94 µm, mean 71 µm) with a spinose/serrated margins ( Figure 5 C). Endplates reduced ( Figure 5 D). Introvert supported by multilocular plates (58–94 µm, mean 76 µm) with jagged margins ( Figure 5 E). Tentacles also supported by multilocular plates (67–189 µm, mean 98 µm) with more jagged margins than those from introvert ( Figure 5 F, G).

Distribution

East and west coast of South Africa, 360– 775 m.

Habitat

Rock.

Remarks

This species, described by Ludwig & Heding (1935), was rediscovered by Thandar (1989c), who pointed out several differences between his specimen and that of the type but despite this, identified his material with Ludwig & Heding’ s species. The differences, according to him, might have warranted the establishment of a new species but hesitated to do so. The current material, also taken from deep waters but off the South African southeast coast, differs from that described by Thandar from off the west coast, but less so than the differences between the west coast specimen and the type. In the present specimen the radial and interradial plates of the calcareous ring are fused at their bases, the processes of the radial plates not clearly fragmented, the body wall tables lack a handle/half ring on one side, and the introvert and tentacle spicules have more pronounced jagged margins. Thandar (1989c) did not mention the presence of endplates in his single specimen but these are recorded in the original manuscript as being well developed. In the present specimen endplates are rare or absent. These differences are perhaps geographic, age or individual variations and more material is required to confirm this. In the meantime the name S. velligera must also suffice for the east coast form. Ludwig & Heding did not comment on the maturity of their specimen but like the west coast specimen, the present specimen is also mature and hence it appears unlikely that this species reaches any appreciable size. Sclerothyone was especially erected to accommodate only Ludwig and Heding’ s species and hence it still remains monotypic. Perhaps Pawson and Miller’ s (1981) Thyone adinopoda and other similar species could be referred to this genus if the generic diagnosis is amended to also include species with scattered podia.

Figures

FIGURE 5. Sclerothyone velligera (Ludwig & Heding, 1935). SAM­A 27902. A. tables from body wall; B. podial tables; C. podial plates; D. part of end­plate; E. introvert plates; F. plates from tentacle stalk; G. plates from tentacle tip; H. calcareous ring and madreporite. A – G scale a.