Synoicum obscurum Kott, 1992

Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), Journal of Natural History 40 (3 - 4), pp. 169-234 : 199

Synoicum obscurum Kott, 1992

Synoicum obscurum Kott 1992a, p 496 .

Distribution

Previously recorded (see Kott 1992a): Victoria (Lakes Entrance); New South Wales (Arrawarra). New record: Tasmanian Canyons (MPA2 area—40.79269 ° E, 144.210916 ° S, 94.6 m) .

Description

The newly recorded colony is a large clump of inverted cones, fixed at their apices to one another. Three or four circles of zooids around common cloacal apertures open on the flat base of the cone, which is at the top of the colony. The internal test is soft and translucent and a thin layer of sand adheres to the outer surface of the cone. The atrial tongue arises from the body wall just anterior to the atrial opening. The stomach is smooth.

Remarks

The present temperate species is distinguished from S. sacculum , which has a lobed colony, by the shape of its conical (rather than cushion-like) lobes and irregular creases in the stomach wall (rather than the mulberry-like stomach wall of S. sacculum ). Only three specimens of this species previously were known. The newly recorded colony has multiple colony lobes rather than the single one previously known.

Kott (1992a) found the irregular creases in the stomach wall that are present also in the newly recorded specimen. These probably are artefacts.