Lissoclinum roseum Kott, 2001

Monniot, Françoise, 2010, Some new data on tropical western Pacific Ascidians, Zootaxa 2561 (1), pp. 1-29 : 10-12

Lissoclinum roseum Kott, 2001

( Figures 8C , 11, 12A )

Lissoclinum roseum Kott, 2001: 322 Fig. 145, 176BC, pls 4C, 20EF; 2004: 2514 Fig. 21G .

Material. Coll. Coral Reef Research Foundation Malaysia, South china Sea, Lyang Lyang atoll, 07°22.12’N – 113°50.22’E, 6m, 23/IX/2006, 0CDN 9559-Y ( MNHN A2 LIS 195 ) .

The very soft colonies are flat cushions with a smooth mucous surface. In life, the zooids seen in transparency appear in systems similar to botryllid rosettes in a vitreous red tunic ( Fig. 12A ). In formalin the zooid distribution disappears in a colourless tunic filled with opaque clear cells. The zooids are more or less completely enclosed in shells made of a layer of spicules, one thoracic and one abdominal. The thoracic musculature is strong and reduces the atrial opening. The lateral thoracic organs are protruding. There is no languet and no muscular appendage ( Fig. 11). The waist is narrow and short without the muscular ring described by Kott (2001). (Some zooids of the type colony have been examined: only one of them possessed a muscular ring around the waist). Ten stigmata were counted in the first branchial row on each side. The ovary is pedunculate ( Fig. 11), anterior to a single testis vesicle. The calcareous capsules made of burr-like spicules 25µm in diameter ( Fig. 8C ) are often incomplete or totally absent. No larvae have been found in the material studied to confirm the identification. The type and paratype have been examined ( QM G308053 - G308312 ): they are in shreds, very contracted. The general aspect and consistency are similar to the Malaysian specimens, with the same clear cells of the tunic. The spicules are the same in shape and size. This species was previously recorded from west Australia and Queensland .

Figures

FIGURE 8. Spicules: A: Didemnum parau. B: Didemnum rodriguesi. C: Lissoclinum roseum. D: Lissoclinum timorensis. Scale bars: 10µm.

FIGURE 12. A: Lissoclinum roseum. B: Lissoclinum timorensis.C: Diplosoma versicolor.

FIGURE 21. Amphicarpa duploplicata: A: body of a zooid, B: part of the posterior left side of the body, scale bar=2mm C: branchial sac.