Polycarpa decipiens Herdman, 1906

Kott, Patricia, 2008, Ascidiacea (Tunicata) from deep waters of the continental shelf of Western Australia, Journal of Natural History 42 (15 - 16), pp. 1103-1217 : 1201-1202

Polycarpa decipiens Herdman, 1906

Polycarpa decipiens Herdman 1906, p. 324 . Kott 1985, p. 163 and synonymy.

Distribution

Previously recorded (see Kott 1985): Queensland (Bowen, Cleveland Bay , Lizard I, and Cape Sidmouth); Papua New Guinea, Sri Lanka, Singapore. New record: Western Australia CSIRO (Lancelin, Stn 76, 100 m, 01.12.05, QM G328454 ; Kalbarri, Stn 96, 435 m, 4.12.05, QM G328472 five specimens) .

Description

The specimen are small fungus-shaped individuals, with circular flat tops, sometimes narrowing to a short stalk on the undersurface and sometimes completely sessile and spherical. The test is thin and brittle with a thin coast of crowded sand. The apertures are sessile and relatively close together on the top of the upper surface. The body wall is a brownish black colour, thin, flaccid and slightly translucent, being thin and not very muscular. The circular nodes surrounded by dark pigment in the outer surface of the body wall that were previously described for this species are, in these specimens, especially conspicuous around the anterior half of the body. Internally, tough white fibres are in the blood vessels of the pharynx and the body wall of one of the specimens (QM G328454). The dorsal tubercle is circular with a deep S-shaped slit in a wide, flat peritubercular area. The anal margin is turned back (like the cuff of a sleeve) and is divided into the long, parallel finger-like lobes previously reported for this species. The distal end of the gut loop encloses the rounded end of a teardrop shaped endocarp. No other endocarps were found on the body wall. Gonads are not deeply embedded in the body wall. They are wide, flat, flask-shaped organs with long male follicles curving around the sac-like ovaries. They are arranged in rows of three to four polycarps, their short ducts from the narrow end of the flask directed toward the atrial aperture. Three rows are on the right side of the body and four on the left.

Remarks

The tough white fibres in the pharyngeal and body wall blood vessels of one of these specimens have previously been reported as characteristic of Polycarpa obscura , a similar species, possibly related, known from temperate waters. Otherwise the characteristic thin weakly muscular body wall in the thin rigid test, the deeply incised slit on the circular dorsal tubercle, the long parallel anal lobes turned back like a cuff, the brown pigmented patches in the outer body wall, and the flask-shaped gonads are all as previously described for this species (see Kott 1985).