Lissoclinum maculatum Kott, 2001

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 : 1194-1195

Lissoclinum maculatum Kott, 2001

( Figure 19C )

Lissoclinum maculatum Kott 2001, p. 310 .

Distribution

Previously recorded (see Kott 2001): Queensland (Lizard I.). New record: Western Australia CSIRO SS10 / 05 (Bald I., Stn 35, 200 m, 24.11.05, QM G328462 ) .

The only two records of this species suggest that it has a wide geographic range around the Australian coast and possibly beyond, and that owing to its inconspicuous form it has been overlooked by collectors.

Description

The colony is a delicate, low dome with a single, terminal, sessile common cloacal aperture on the upper surface. Internally the zooids cross the vast common cloacal cavity in strands of test connecting the surface with the basal layer of test. Spicules are crowded in a single layer in the surface test. They are up to 0.03 mm diameter and burr-like, with numerous rod-like rays with pointed to flattened tips.

Zooids have a more or less rectangular outline with the margin of the atrial aperture withdrawn ventrally to expose the branchial sac directly to the common cloacal cavity. The stigmata are long. The gut is folded up behind the thorax and a large yellow egg is behind the almost horizontal gut loop at the posterior end of the zooid. The testis was not detected in this specimen.

Remarks

The colony and spicules resemble those of Trididemnum spumosum , although the species are separated by their generic characters and size of the spicules, those of T. spumosum being only 0.02 mm diameter. The colony also resembles that of Didemnum cynuus although the latter species has characteristic stellate spicules that are very different from those of the present species (see above).

Family STYELIDAE Sluiter, 1895

Sub-family STYELINAE

Figures

Figure 19. Scanning electron micrographs of didemnid spicules: A, Trididemnum grandistellatum, QM G328007; B, Trididemnum sibogae, QM G328421; C, Lissoclinum maculatum, QM G328462.