Didemnum rodriguesi Rocha & Monniot F., 1993

Monniot, Françoise & Monniot, Claude, 2001, Ascidians from the tropical western Pacific, Zoosystema 23 (2), pp. 201-383 : 271

Didemnum rodriguesi Rocha & Monniot F., 1993

( Figs 55 ; 120F )

Didemnum rodriguesi Rocha & Monniot F., 1993: 261 , figs 1; 2, Brazil and New Caledonia. — Monniot C. et al. in press, Sodwana Bay, South Africa. MATERIAL EXAMINED. — Papua New Guinea. Milne Bay, China Straits, 10°34.50’S, 150°40.73’E, 23 m, 10.VI.1998 ( MNHN A2 DID. C 463 ) .

DESCRIPTION

The colonies are thin red crusts covering many kinds of substrates ( Fig. 120F ). The surface is smooth but appears as finely prickled and pitted, due to the distribution of spicules in the surface layer of the colony. The spicules are dense throughout the thickness of the colony: they are stellate, up to 40 µm in diameter.

The zooids have a wide cloacal aperture. The lateral thoracic organs are above the third transverse vessel. The thorax is narrowed posteriorly. The gut forms a twisted loop. There is a single testis follicle which is covered by about seven turns of the sperm duct.

The developed larvae ( Fig. 55 ) protrude at the colony surface. They have three short adhesive papillae encircled by seven to eight pairs of ampullae. They are not gemmiparous.

REMARKS

This richly coloured Didemnum is well-characterised by the microscopical pattern of its colony surface. Its distribution is surprisingly large, as it occurs in Papua New Guinea, New Caledonia, South Africa, and Brazil.

Figures

FIG. 55. — Didemnum rodriguesi Rocha & Monniot F., 1993, larva. Scale bar: 0.5 mm.

FIG. 120. — A, Didemnum algasedens n. sp.; B, Didemnum cuculliferum (Sluiter, 1909); C, Didemnum lacertosum Monniot F., 1995; D, Didemnum madeleinae n. sp.; E, Didemnum obscurum Monniot F., 1969; F, Didemnum rodriguesi Rocha & Monniot F., 1993.