Didemnum moseleyi ( Herdman, 1886 )

Monniot, Françoise & Monniot, Claude, 2001, Ascidians from the tropical western Pacific, Zoosystema 23 (2), pp. 201-383 : 270

Didemnum moseleyi ( Herdman, 1886)

Leptoclinum moseleyi Herdman, 1886: 272 .

Didemnum moseleyi . — Monniot F. & Monniot C., 1996: 157, Micronesia, and synonymy.

MATERIAL EXAMINED. — Federated States of Micronesia. Pohnpei, NE lagoon, Tehpehk Island, bath sponge farm growing on nylon line, 6°57.68’N, 158°17.85’E, 8 m, 13.X.1996 ( MNHN A2 DID.C 419).

Papua New Guinea. Louisiade Archipelago, Deboyne Lagoon, Nivani Island, 10°47.46’S, 152°23.08’E, 10 m, 30. V.1998 ( MNHN A2 DID.C 466).

Didemnum obscurum Monniot F., 1969 ( Fig. 120E )

Didemnum obscurum Monniot F., 1969: 453 , fig. 14. Type locality: Dakar; 1995: 319, fig. 12, pl. 2f, New Caledonia. — Monniot C. & Monniot F. 1997: 1626, Bahrain. — Monniot C. et al. in press, figs 23E, F ; 25D, South Africa.

MATERIAL EXAMINED. — Tonga. Tongatapu, Ualanga Lalu Reef, 21°06.02’S, 175°11.56’W, 18 m, 18.XI.1997 ( MNHN A2 DID.C 452).

DESCRIPTION

The colonies are very dark inside but somewhat lighter externally, due to the spicules in the superficial layer ( Fig. 120E ). There is abundant mucus in the cloacal cavity. The colony is thick and not brittle. The zooids are black. The oral siphon is short. The cloacal aperture is wide with a very large bilobed languet in zooids near the common cloacal aperture but smaller elsewhere. The retractor muscle parts from the upper part of the oesophageal peduncle. The abdomen has about the same size as the thorax. The single testis follicle is large, flat and covered by the coiled sperm duct. The oocyte is large and protruding. The larvae are black with three short, stout adhesive papillae and a crown of numerous, joined digitiform ampullae.

REMARKS

All characters correspond well to previous descriptions, and the spherical spicules with many short, pointed rays are also similar. This species is widely distributed; it occurs as well in Senegal, from which it was described, and in the Indian Ocean and the western Pacific Ocean.

Figures

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.