Lissoclinum bistratum ( Sluiter, 1905 )

Monniot, Françoise, 2010, Some new data on tropical western Pacific Ascidians, Zootaxa 2561 (1), pp. 1-29 : 10

Lissoclinum bistratum ( Sluiter, 1905)

( Figures 7D )

Didemnum bistratum Sluiter, 1905: 103 .

Lissoclinum bistratum: Monniot F. & Monniot C. 2001: 283 . Kott 2001: 298; 2004: 64; 2005: 2460 Fig. 17E .

Material. Coll. Coral Reef Research Foundation, Malaysia, South China Sea , Ardasier Reef, 07°36.67’N – 113°59.90’E, 5–22m, 18/IX/2006, 0CDN 9450-I ( MNHN A2 LIS 196 ) .

Often recorded in the Pacific and Indian oceans, these small green colonies have symbiotic algae in the common cloacal cavity ( Fig.7D ). The larva 1mm long is gemmiparous, with 3 adhesive papillae and 8 vesicles on each side. The spicules are composed of rod-like rays in spheres 20 to 30µm in diameter.

All anatomical characters of L. bistratum are the same as those of Lissoclinum timorense ( Sluiter, 1909) , except that the later has a spiky colony surface and larger and stellate spicules. L. bistratum probably does not represent a single species. The closely allied Lissoclinum voeltzkowi (Michaelsen 1920) could not be differentiated by the zooids, larvae or spicules and had been considered a synonym of L. bistratum , but chemical studies have shown differences between both species in the same location (see discussion in Monniot & Monniot, 2001: 283).

Figures

FIGURE 7. A: Didemnum nocturnum. B: Didemnum parau. C: Didemnum rodriguesi. D: Lissoclinum bistratum.

FIGURE 17. Eudistoma vulgare: digestive loop, scale bar: 0.5mm.