Staurothyone rosacea ( Semper, 1869 )

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 : 33-34

Staurothyone rosacea ( Semper, 1869)

Figure 11

Thyone rosacea Semper, 1868: 242 (nom.nud.); 1869: 122, pl.1, fig. 2 a–c; Lampert, 1885: 159, pl. 1, fig. 3.

Thyone sargassi Lampert, 1889: 840 , fig. 10.

Staurothyone rosacea Panning, 1949: 418 , fig. 5; 1964: 159, fig. 1.

Type

Hamburg Museum, Germany, 2901.

Type locality

Red Sea.

Previous South African record

None

Material examined

SAM­A27910, between Bhanga Nek and Kosi Bay, No. 13 reef, KwaZulu­Natal, D. Herbert, SCUBA­dive, 12–20 vii 1987, 6– 18 m, 1 spec.

Description

Specimen previously dried up but prolonged soaking in alcohol softened the body wall to some extent. Form cylindrical, slightly U­shaped, measuring 22 mm along trivium and 3.5 mm in breadth in mid­body. Colour dark reddish brown ventrally, paler dorsally. Podia usually restricted to ambulacra, two rows dorsally and 3–4 rows ventrally, with few also scattered in interambulacra of ventral surface. Mouth anterior, tentacles extremely bushy but number and size variation could not be determined. Anus terminal, encircled by five calcareous teeth, easily demonstrated. Calcareous ring ( Figure 10 C) well developed, interradial plates longer than radial plates with a shallow depression on their outer surface. Polian vesicle single, sac­like. Stone canal not observed.

Spicules of body wall include large crosses ( Figure 11 A) and minute rosettes ( Figure 11 B). Podial deposits include rods with digitated ends. No indication of any secondary branchings to the two primary dichotomous branches of the crosses.

Distribution

West Indian Ocean, including Red Sea.

Remarks

Of the three other species currently classified in Staurothyone , S. vercoi ( Joshua & Creed, 1915) is apparently a 20­tentacled form and hence referable to another genus (see Rowe & Gates 1995); S. distincta ( Clark, 1938) from North Australia is distinct in possessing, in addition to the crosses and rosettes in the body wall, peculiar minute ‘oblong particles’; and S. inconspicua ( Bell, 1887) is a South Australian­Tasmanian species, very close to the Indo­West Pacific S. rosacea and suspected by both Clark (1938) and Panning (1949) to be synonymous with it. However, according to O’ Loughlin (1991) and Materia et al. (1991), S. inconspicua is a seasonal coelomic brooder, while Rowe (pers. comm.) is of the opinion that there are also differences in proportions of crosses in the two species. The current specimen differs from the holotype, re­described by Panning (1949, 1964), in the ambulacral restriction of the podia, the shape of the plates of the calcareous ring, especially the anterior tip of the interradial plates, and the posterior margin of the ring. These are perhaps growth characteristics since the type (40 mm long) is almost twice as large as the specimen here described.

Figures

FIGURE 10. Plesiocolochirus tessellarus (Cherbonnier, 1970). SAM­ 27909. A. large­knobbed buttons from dorsal body wall; B. side view of buttons; C. plate / scale from dorsal body wall; D. baskets from dorsal body wall; E. side view of baskets from dorsal body wall; F. baskets from dorsal podia; G. rods from dorsal podia; H. small­knobbed plates from dorsal podia; I. end­plate from dorsal podium; J. part of end­plate from ventral podium; K. plates from tentacles; L. tentacle rods. A­C & G­L scale a; D­F scale b.

FIGURE 11. Staurothyone rosacea (Semper, 1869). SAM­A 27910. A. crosses from body wall; B. rosettes from body wall; C. calcareous ring.