Lissoclinum levitum 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 : 2465-2466

Lissoclinum levitum Kott, 2001

( Figure 21H )

Lissoclinum levitum Kott 2001, p 307 ; 2004a, p 767; 2004b, p 2512.

Distribution

Previously recorded (see Kott 2001, 2004a, 2004b): South Australia (Great Australian Bight, Ward I., Kangaroo I.). New records: South Australia (Kangaroo I., SAM E3254); Tasmania (Port Davey, SAM E3265).

Description

In preservative, the newly recorded colonies are thin, flexible, grey sheets with groups of zooids suspended in extensive common cloacal cavities by test ligaments connecting surface to basal test, including the extension of the basal test up into the central core of projecting lobes. At the surface the test ligament subdivides to separate the thoraces from one another. Evenly spaced branchial apertures are depressed into the soft surface. Only sparse spicules are in the internal test, which is cloudy with the small, spherical bodies that have been observed in other species of this genus. Spicules are to 0.05 mm diameter and have the numerous blunt, crowded rays previously reported for this species. In life, the surface of the pink to white translucent colonies are produced into elevations with large, terminal, smooth-rimmed common cloacal apertures.

Zooids are as previously described for the species but have numerous oesophageal buds. Gonads were not detected.

Remarks

Preserved specimens of this species can be confused with the sympatric L. clavatum sp. nov., owing to their similar extensive common cloacal canals and similar (but slightly larger in the present species) spicules. However, its spicules are not so crowded, and the terminal common cloacal apertures, raised on elevated surface lobes of the translucent colonies of the present species (see also Kott 2004a) are entirely different from the numerous sessile common cloacal apertures of the opaque colonies of L. clavatum .

Previously known only from South Australia, the new record from Tasmania extends the southern range of this species.

Figures

Figure 21. In situ images of: (A) Trididemnum amiculum (SAM E3263); (B) Trididemnum nobile (SAM E3262); (C) Trididemnum pigmentatum (QM G308714); (D) Trididemnum savignii (QM G308721); (E) Lissoclinum calycis (QM G308749); (F) Lissoclinum clavatum (SAM E3260, holotype); (G) Lissoclinum concavum (SAM E3242); (H) Lissoclinum levitum (SAM E3254).