Polyclinum constellatum Savigny, 1816

Monniot, Françoise & Monniot, Claude, 2001, Ascidians from the tropical western Pacific, Zoosystema 23 (2), pp. 201-383 : 223-224

Polyclinum constellatum Savigny, 1816

Polyclinum constellatum Savigny, 1816: 189 . Type locality: Red Sea. — Monniot C. & Monniot F. 1987: 83, Polynesia.

MATERIAL EXAMINED. — Mariana Islands. Guam, Apra Harbour off Buoys, 0-3 m, 12. VI.1997 ( MNHN A1 POL.B 70).

Polyclinum psammiferum Hartmeyer, 1911 ( Figs 16 ; 114B )

Polyclinum sabulosum Sluiter, 1909: 96 , preoccupied by Polyclinum sabulosum Lahille, 1890 . Type locality: Indonesia.

Polyclinum psammiferum Hartmeyer, 1911 . Replacement name.

Polyclinum solum Kott, 1992a: 458 , fig. 31, Queensland; 1998: 124.

MATERIAL EXAMINED. — Palau. Koror, Ngermerrangel Island, Flatworm Lake, marine lake, 7°19.12’N, 134°30.40’E, 0.5 m, 23.VII.1997 ( MNHN A1 POL.B 69).

DESCRIPTION

The colonies are pale yellow cushions ( Fig. 114B ), 1 cm thick and about 3.5 cm in diameter, with a translucent tunic allowing one to see yellow zooids through the embedded sand. The systems are circular or in concentric circles around the common cloacal apertures. The tunic has a soft consistency.

The zooids are 6 to 8 mm long. The oral siphon has six pointed lobes. The cloacal siphon is a narrow tube ( Fig. 16A ). The cloacal languet is thin and long with a pointed tip ( Fig. 16A, C ). The oral tentacles are numerous, in three orders of size. The branchial sac has 15 to 18 rows of

A-C stigmata with 22 stigmata in a half row in the middle of the thorax.

There is an unperforated band along the dorsal line, and the rapheal languets are progressively displaced to the left side on the transverse vessels. There are no papillae or undulations on the rim of the transverse vessels.

The abdomen has the usual shape of the genus but the gut loop is only slightly twisted ( Fig. 16A ). The peduncle of the post-abdomen arises from the posterior part of the gut loop; the sperm duct makes a curl at this level ( Fig. 16A ). The elongated postabdomen contains a double row of testis follicles. The ovary lies mid-way down the testis line ( Fig. 16B ).

The larvae ( Fig. 16D ) are incubated in the cloacal cavity. They have an elongated trunk and three long adhesive papillae alternating with finger-like ampullae. In addition there are four round ampullae on each side of the trunk at the base of the adhesive papillae. A crystal of calcium oxalate ( Fig. 16D ) is present in the larval body, as usual in the genus Polyclinum . Two clusters of small vesicles, one dorsal and one ventral, lie on each side of the trunk ( Fig. 16D ).

REMARKS

This species seems to be intermediate between the genera Aplidiopsis and Polyclinum by virtue of the absence of papillae on the transverse vessels and a slightly twisted gut loop. Nevertheless, it has the larval calcium crystal characteristic of the genus Polyclinum .

The species is recorded here for the third time. It has been found in Indonesia and Queensland.

Figures

FIG. 16. — Polyclinum psammiferum Hartmeyer, 1911; A, B, two parts of a zooid; C, thorax; D, larva. Scale bars: A-C, 1 mm; D, 0.25 mm.

FIG. 114. — A, Monniotus papillosus n. sp.; B, Polyclinum psammiferum Hartmeyer, 1911; C, Pseudodistoma aureum (Brewin, 1957); D, Pseudodistoma digitata n. sp.; E, Pseudodistoma fragile Tokioka, 1958; F, Pseudodistoma novaezelandiae (Brewin, 1950).