Leptoclinides prunus, Kott, 2010

Kott, Patricia, 2010, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part 2), Journal of Natural History 38 (26), pp. 2455-2526 : 2473-2476

Leptoclinides prunus sp. nov.

( figures 3 , 16B )

Distribution. Type locality: Victoria (Portsea Pier on piles 4–5 m, coll. K. Gowlett Holmes, 26 June 1999, holotype SAM E2915).

Description. The holotype is an encrusting sheet with a quilted surface, formed by depressions in the surface test over the primary common cloacal canals that surround the circular stands of solid test protruding slightly from the surface. A thin superficial layer of bladder cells contains stellate grey-black pigment bodies mixed with evenly, but sparsely, distributed spicules. Some relatively large spots created by patches of crowded spicules are scattered in the bladder cell layer on some parts of the surface. Branchial apertures are depressed into the surface along each side of the primary common cloacal canals, but they are inconspicuous, without a marginal row of spicules. Large common cloacal apertures are on slight prominences at some of the junctions of primary common cloacal canals. The common cloacal apertures are scattered over the surface of the colony rather than around its margins. Deep posterior-abdominal common cloacal cavities are found beneath common cloacal apertures, but these become oesophageal canals toward the outer margins of the colony.

Spicules are present only in the zooid layer and lining the common cloacal canals. In the lower half of the colony the test is firm and translucent. Spicules are stellate, to 0.063 mm diameter, with seven to nine rays in optical transverse section, the rays with relatively short, round, pointed, chisel-shaped or truncated tips.

Zooids have seven coils of the vas deferens.

Remarks. Of the Leptoclinides spp. with similar common cloacal systems and spicules absent from the lower half of the colony, the tropical L. constellatus Kott, 2001 lacks the pigment cells and has larger zooids and spicules; while L. rigidus Kott, 2001 has only five coils of the vas deferens and larger spicules than the present species. The temperate L. seminudus Kott, 2001 has larger spicules and more (eight) vas deferens coils, and L. exiguus Kott, 2001 has fewer (five) vas deferens coils and different pigmentation. All of these species have more (9–11) spicule rays than the present species. Other temperate species, such as L. compactus Kott, 2001 with spicules missing from the lower half of the colony, have different common cloacal systems with a terminal common cloacal aperture on conspicuous lobes projecting from the surface of the colony, rather than the quilted surface of the present species.

Leptoclinides rigidus Kott, 2001

( figure 16C )

Leptoclinides rigidus Kott, 2001: 77 and synonymy.

Distribution. Previously recorded (see Kott, 2001): Western Australia (Montebello Is), Queensland (Whitsunday Is, Deloraine I., Hawksbury I.), Northern Territory (Wessel I.);? Papua New Guinea. New records: Western Australia ( Ashmore Reef, WAM 1035.88), Northern Territory (Darwin Harbour, QM G308614).

Description. The surface of the firm, gelatinous colony has a mosaic of oval to irregular elevated areas separated by circular depressions over the primary common cloacal canals. These deep canals expand into extensive posterior abdominal common cloacal cavities that separate the lower basal test from the upper zooid-bearing layer. In the zooid-bearing layer of test there is black pigment mixed with the spicules, which are sparse elsewhere. Spicules are to 0.082 mm diameter and have 9–11 pointed or chisel-tipped rays in optical transverse section. Atrial apertures are on long posteriorly orientated siphons opening into the posterior abdominal common cloacal cavities. The abdomina are bent up ventral to the thoraces or are vertical loops in teardrop-shaped abdomina. Six coils of the vas deferens surround seven or eight testis follicles.

Remarks. Although the colony has the same mosaic of elevated areas on the surface as in L. aciculus , it is distinguished by its spicules, which have fewer rays. The spicules have more rays and are larger than L. sulawesi .

Leptoclinides sulawesi Monniot and Monniot, 1996

( figure 16D )

Leptoclinides sulawesi Monniot and Monniot, 1996: 180 ; Kott, 2001: 83.

Distribution. Previously recorded (see Kott, 2001): Western Australia (Dongara), New South Wales (Twofold Bay), Indonesia, Palau Is. New records: NW Australia ( Ashmore Reef, WAM 996.88).

Description. Small oval cushions about 1 cm long, with about three randomly distributed common cloacal openings on slight prominences on the upper surface. A crowded layer of spicules is on the upper surface and another is on the lower surface, and these form a capsule that surrounds the whole colony. Spicules are not present in the remainder of the colony. Spicules are stellate, to 0.075 mm diameter, with seven to nine chisel-tipped rays in optical transverse section. Black pigment, mixed with spicules around each common cloacal aperture in the surface test and in the zooid layer in the upper half of the colony, fades out toward the base. A large common cloacal cavity is posterior to the zooids in the centre of the lower part of the colony and abdomina are around the periphery.

Zooids are relatively small, with about 12 stigmata in the anterior row, a posteriorly orientated atrial aperture, a gut loop bent at right angles to the antero-posterior axis of the body, five testis follicles surrounded by seven coils of the vas deferens.

Remarks. The newly recorded specimens are as previously described except for the small cushion-shaped colonies. Only further material can resolve the true identity of these newly recorded colonies, which could be found not to be conspecific with L. sulawesi .

Leptoclinides variegatus Kott, 2001

( figure 16E )

Leptoclinides variegatus Kott, 2001: 86 and synonymy.

Distribution. Previously recorded (see Kott, 2001): South Australia (Great Australian Bight, Spencer Gulf, Gulf St Vincent, Investigator Strait). New records: South Australia (Gulf St Vincent, SAM E3206; Kangaroo I., SAM E3221).

Description. The tough, robust, sheet-like colonies have patches of black grey pigment in a white background, crossed by veins of orange pigment mixed with the spicules in the superficial test. The spicules are relatively small (to 0.09 mm diameter) and have 11–13 rays in optical transverse section, usually with chisel-shaped or truncated tips. They are not crowded and the colony is slightly translucent. Spicules become sparser toward the base of the colony and often are missing altogether from the basal test. Large sessile common cloacal apertures are randomly distributed over the otherwise smooth or slightly quilted surface. Gonads were not detected.

Remarks. Apart from the distinctive marbled colour pattern, the firm consistency of the colony without conspicuous surface depressions over the common cloacal canals, the relatively small zooids, the conspicuous chisel-shaped tips of the relatively large spicules, and their distribution, together distinguish the species.

Figures

FIG. 3. Leptoclinides prunus (SAM E2915). (A) Surface view of colony; (B) zooid. Scale bars: 5.0 mm (A); 0.1 mm (B).

FIG. 16. (A) Leptoclinides maculatus (SAM E2916); (B) Leptoclinides prunus (SAM E2915); (C) Leptoclinides rigidus (WAM 1035.88); (D) Leptoclinides sulawesi (WAM 996.98); (E) Leptoclinides variegatus (SAM E3221); (F) Polysyncraton catillum (WAM 1046.88); (G) Polysyncraton cuculliferum (QM G308616); (H) Polysyncraton dromide (QM G308596).