Molgula delicata Monniot C.

Kott, Patricia, 2009, Taxonomic revision of Ascidiacea (Tunicata) from the upper continental slope off north-western Australia, Journal of Natural History 43 (31 - 32), pp. 1947-1986 : 1981-1982

Molgula delicata Monniot C. and F., 1991

( Figure 3F ) Molgula delicata Monniot C. and F., 1991, p. 426; 2003, p. 738. Sanamyan K. and N. 1999, p. 1864.

Distribution

Previously recorded ( Monniot F and Monniot C 2003): New Caledonia; New Zealand. New record: CSIRO 05 / 07 western Australia (Station 176-032, Kulumburu, 13.23 S 123.50 E, 392 m, Sled tow 16.5.07, QM G328510 ) .

The depth range recorded for this species is 400–1026 m.

Description

The newly recorded specimen is dorso-ventrally flattened, oval in outline, about 2 cm long and is covered with fine hairs to which sand adheres. The apertures are sessile and about one-third of the body length apart in the centre of the upper surface. Fine circular muscles surround each of the apertures and equally fine bands radiate from each of the apertures over the anterior half of the body wall. A fine transverse muscle forms a shallow arc across the dorsal mid line between the apertures. About 12 delicate, branched branchial tentacles are of various sizes. The dorsal lamina is a plain-edged fold. A small, simple, oval, longitudinally oriented opening is on the dorsal tubercle. A row of eight deep conical infundibula, their bases meeting in the interspaces between adjacent folds, is in each of the six branchial folds on each side of the body. About five or six internal longitudinal branchial vessels are on each fold. The gut forms a slightly curved loop, open at the pole, in the ventral part of the left side of the body The stomach is small and almost spherical with about four broad, smooth longitudinal folds in its wall. A kidney is in the centre of the right side of the body wall. In this specimen a three-dimensional, circular mass of blood vessels is clumped together on the right, dorsal to the kidney but gonads were not detected.

Remarks

The long flexible test hairs and the six branchial folds with eight tall infundibula in each are like M. rima , which has longer siphons than the present species and lacks its characteristic short stomach, with four broad folds and its simple, curved gut loop.

Figures

Figure 3. (Continued). (E) body opened along ventral midline showing gonads, endocarps and gut loop. (F) Molgula delicata (QM G328510), body seen from above showing muscles radiating from around the apertures and extending halfway down the body wall and the fine transverse muscle crossing the dorsal mid-line. Scales: A, 1.0 cm; B, D, 0.5 cm; C, 0.5 mm; E, 1.0 mm; F, 2.0 mm.