Polysyncraton rica Kott, 2001

Kott, Patricia, 2005, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (Part 3), Journal of Natural History 39 (26), pp. 2409-2479 : 2437

Polysyncraton rica Kott, 2001

( Figure 19E )

Polysyncraton rica Kott 2001, p 130 ; 2004a, p 745 and synonymy; 2004b, p 2485.

Polysyncraton pedunculatum: Kott 2001, p 121 (part, specimen QM GH2387 from Flinders I., Plate 6D).

Distribution

Previously recorded (see Kott 2001, 2004a, 2004b): South Australia (Great Australian Bight, Spencer Gulf, St Vincent Gulf, Investigator Is, Flinders I., Kangaroo I.). New record: South Australia (Kangaroo I., SAM E3245).

Remarks

The newly recorded colony resembles those previously described in its soft, fleshy consistency, smooth surface with a superficial layer of bladder cells and lobes or in this case with part of the surface overgrowing and partly fusing with the other half. Spicules are evenly distributed throughout but are not crowded, and some are characteristically bilaterally (rather than radially) symmetrical with rays on one side longer than those on the other. Zooids, crowded in a layer at the surface, have a robust rectangular thorax with a conspicuous, strong, tapering retractor muscle and three coils of the vas deferens around a circle of four or five testis follicles.

The species is unusual in this genus in having only a small atrial tongue. The species has not been recorded outside South Australian waters.

Specimen QM GH2387 from Flinders I., erroneously assigned to P. pedunculatum , has been re-examined and found to belong to the present species. Although the in situ photograph of the living colony ( Kott 2001, Plate 6D) is dramatically different from the deck photograph ( Kott 2001, Plate 6G), the preserved colonies are identical.

Figures

Figure 19. In situ images of: (A) Polysyncraton glaucum (QM G308736); (B) Polysyncraton papyrus (SAM E3253); (C) Polysyncraton pedunculatum (SAM E3272); (D) Polysyncraton purou (QM G308707); (E) Polysyncraton rica (SAM E3245); (F) Didemnum cilicium (SAM E3251, holotype); (G) Didemnum corium (SAM E3249, holotype); (H) Didemnum cygnuus (QM G308716).