Polycarpa pigmentata (Herdman, 1906)

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 : 1975

Polycarpa pigmentata (Herdman, 1906)

(Figure 2D–E)

Styela pigmentata Herdman, 1906, p. 118 .

Polycarpa pigmentata: Kott 1985, p. 192 and synonymy. Monniot F.and C. 2001, p. 329.

Distribution

Previously recorded ( Kott 1985; Monniot F and Monniot C 2001): western Australia (Cape Jaubert, Cockburn Sound); Victoria (Bass Strait); Queensland (Moreton Bay, Bowen, Townsville and the Great Barrier Reef north to Flinders Reef); Papua New Guinea, New Caledonia, Palau Is., Philippines, Solomon Is., Gilbert Is., Marshall Is., Indonesia, Sri Lanka, Japan, the Red Sea. New records: CSIRO 05/07 western Australia (Station 188-100 and 188-101, Ashmore, 12.45 S 123.60 E, 95 m, Beam trawl, 17.5.07, QM G328569, QM G328570).

Description

One of the specimens (QM G328570) is the basal part of a leathery test attached to a hard rocky substrate with encrusting bryozoans. It is assigned to this species solely on the grounds that this piece of test resembles that of the other (entire) specimen. The latter, is about 8 cm long, 6 cm deep and laterally flattened. The four-lobed branchial aperture is at one end of the dorsal surface and the atrial aperture on a short siphon about halfway along the more or less horizontal upper surface is directed ventrally. The postero-ventral part of the body is inflated.

Internally a slightly asymmetrical C-shaped slit is on the dorsal tubercle at the top of a short peri-tubercular V. Four branchial folds are on each side, with longitudinal vessels arranged according to the following formula: DL (12) 6(20) 6(24) 9(16) 6 E. The gut loop is straight, the ascending and descending limbs being almost the same length and almost parallel. The stomach, almost half the length of the proximal limb of the loop is narrow, elliptical and its wall is lined with long parallel folds. The anal rim has about 18 small rounded lobes. Two long, narrow, flattopped endocarps are enclosed in the narrow gut loop end to end. Only traces of polycarps were detected deeply embedded in the body wall of this specimen which appears to be senescent.

Remarks

The specimen resembles previously recorded specimens assigned to this species, especially in the tough consistency of the test and the general shape of the body. Although Kott (1985) reports that the relatively short rectum is bent at right angles to the gut loop, her figure ( Kott 1985, fig. 89e) shows a gut loop with enclosed flat-topped endocarps very like the present specimen. It is possible that this is a variable condition depending on the contraction and age of the specimen.