Leptoclinides decoratus, 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 : 2469-2473

Leptoclinides decoratus sp. nov.

( figures 2 , 15G )

Distribution. Type locality: South Australia (Kangaroo I., The Arch between Snug Cave and Western River Cave on rock wall, coll. K. Gowlett Holmes, 8 March 2002, holotype SAM E3212; rock E of Snug Cave, coll. K. Gowlett Holmes, 10 March 2002, paratype SAM E3214).

Description. In life the colonies look glassy with randomly distributed, embedded blue-black spots of pigment and, mixed with them and in the same size range, spherical white clumps of tightly crowded spicules. In preservative, the black and white spots persist in reddish brown colonies, which have a fleshy appearance. However, these colonies are especially tough, the translucent test is difficult to cut and the zooids are impossible to remove. The surface of the holotype colony is elevated into a broad rounded ridge with a large circular, elevated common cloacal aperture at one end of the ridge. The superficial layer of test contains pale brown-orange pigment mixed with an even, but relatively sparse, thin layer of spicules. Spicules are even sparser in a layer lining the very extensive posterior abdominal common cloacal cavity and another thin, sparse layer of spicules is on the base of the colonies. Spicules are absent from other parts of the colony. The surface ridges are the result of thickening of the basal test.

Clean scanning electron micrographs of the spicules were not obtained, and a considerable amount of amorphous material obscures them, despite efforts to free them by the usual method of incinerating strips of spicule-containing test. The spicules are small, stellate, to 0.04 mm diameter, with five to seven and sometimes nine conical, pointed rays in optical transverse section.

Zooids are relatively large. Branchial siphons are robust cylinders without branchial lobes around the apertures. Posteriorly orientated atrial siphons have a small lip on the posterior rim of the aperture. There appear to be about 10 stigmata per row, but these could not be counted accurately. Gonads were not detected in these specimens.

Remarks. Leptoclinides maculatus Kott, 2001 has similar black spots in the test, although its posterior abdominal common cloacal cavities are never so extensive and the spicules are larger with more spicule rays. Larger spicules with more rays are also in L. variegatus Kott, 2001 . Leptoclinides compactus Kott, 2001 has similar tough colonies, with surface swellings and terminal common cloacal apertures, but it has a superficial layer of bladder cells, which is lacking in the present species and although its spicules have a similar number of rays, larger spicules (to 0.06 mm diameter) occur in L. compactus and the ray tips often are chisel-shaped or truncated.

Leptoclinides exiguus Kott, 2001

Leptoclinides exiguus Kott, 2001: 62 and synonymy; not Kott, 2004 (~ L. maculatus , see below).

Distribution. Previously recorded (see Kott, 2001): South Australia (Gulf St Vincent, Spencer Gulf, Kangaroo I.); Victoria (Port Phillip Bay, Western Port, Gabo I.). New records: Victoria (Western Port, QM G398569).

Description. In preservative, the newly recorded colony has blue-black piebald markings resulting from fine pigment cells beneath a thin, superficial layer of bladder cells. Spicules are present throughout the test but they are never crowded and they become sparser toward the base of the colony. Zooids have a number of male follicles surrounded by five coils of the vas deferens.

Remarks. Although Leptoclinides exiguus: Kott, 2001 (part, specimen QM G301615) is a figured specimen, it is not the holotype of L. exiguus Kott, 2001 as Kott (2004) erroneously stated. This specimen and others from South Australia (SAM E2096-7) with similar colonies, spicules and zooids with eight coils of the vas deferens ( L. exiguus: Kott, 2004 ) appear to be specimens of L. maculatus Kott, 2001 incorrectly assigned to the present species.

Leptoclinides levitatus Kott, 2001

( figure 15H )

Leptoclinides levitatus Kott, 2001: 69 .

Distribution. Previously recorded (see Kott, 2001): Western Australia (Warnbro Sound), Queensland (Little Black Reef, Penrith I.). New records: Northern Territory (Darwin Harbour, QM G308603, G308624).

Description. The surfaces of the newly recorded slab-like colonies (up to 6 cm long and 3 cm thick) are raised into long, sinuous rounded ridges. One colony (QM G308603) has large common cloacal apertures with frilled margins, along one side of the colony, at the outer extremity of each curve, suggesting that the slab may have been on a vertical surface, the margin with the common cloacal cavities being along the upper edge. Colonies are soft and gelatinous but quite turgid. Spicules are in a single layer in the surface, and in a sparse layer lining the vast central common cloacal cavity which has large vertical canals penetrating the surface layer of test around the zooids. The surface layer of spicules penetrates into the test that forms the rim around the common cloacal apertures but they are sparse in the remainder of the colony. One of the photographed colonies appears to have been black, although it is recorded in the collector’s note as brown (QM G308603). The other newly recorded colony appears to have been reddish orange. Both are colourless in preservative. The spicules are relatively small (to 0.04 mm diameter) with attenuated tips on the pointed conical rays, which are variable in length and number up to 15 in optical transverse section.

Zooids are large, with false siphons formed by the velum in the base of the branchial siphon, short atrial siphons, fine longitudinal muscles in the parietal body wall, and especially fine and few muscles in the transverse sinuses between the rows of stigmata. The paired dorsal pharyngeal muscles, which generally are inconspicuous in this genus, were not detected at all in this species. About 16 stigmata are in the anterior row of the branchial sac but the number reduces to about 12 in the posterior row. The gut forms a double loop and the vas deferens makes a sinuous curve across the outside of the testis follicles.

Remarks. The colonies resemble those previously described for this species, including the variations in colour, previously recorded and photographed specimens having been pink or bright orange-red or black in life and colourless in preservative. The spicules are, as in other species of the dubius group (see Kott, 2001), in a thin layer in the surface of the colony. Also, the zooids have the characters previously identified as characteristic of this group of species, having a branchial velum at the base of the branchial siphon, numerous stigmata, a double curved gut loop and an S-shaped curve of the vas deferens over the outside of the testis follicles. The only departure from previously recorded specimens is the absence of the smaller almost globular spicules that Kott (2001) reported, although the attenuated points on the conical spicule rays are exactly like those previously described.

Leptoclinides maculatus Kott, 2001

( figure 16A )

Leptoclinides maculatus Kott, 2001: 72 .

Leptoclinides exiguus: Kott, 2001: 62 (part, specimen QM G301615); 2004.

Distribution. Previously recorded (see Kott, 2001, 2004): South Australia (Yorke Peninsula to Investigator Strait); Western Port (Victoria). New records: South Australia (Kangaroo I., SAM E2916); Victoria (Western Port, QM G308556, G308563-4).

Description. Colonies are encrusting sheets varying in colour from white with black spots or with patches of grey to an even black. In preservative colours are similar, though lighter, and black spots are in the grey areas. Sometimes the pigment is more concentrated in the surface grooves over the primary common cloacal canals that surround grey surface elevations over the solid stands of test (where the pigment layer is diluted by the depth of the white spicules in the upper part of the colony). The black pigment is in branching bodies in a layer beneath the surface, where it is mixed with spicules. Randomly distributed common cloacal apertures with frilled rims are at the junctions of the primary common cloacal canals. Spicules are crowded in a layer in the upper, zooid-bearing half of the colony, but are only very sparse in, or absent from, the lower half of the colony where the test is translucent. They are to 0.065 mm in diameter, and have 9–11 rays with pointed or chisel-shaped tips in optical transverse section.

Zooids have four rows of oval stigmata, a long oesophageal neck, eight coils of the vas deferens around a circle of four or five testis follicles.

Remarks. The sympatric L. exiguus Kott, 2001 has been confused with the present species (see L. exiguus , above), having similar colonies and spicules. It has more intense pigmentation, with, in life, a vivid yellow/black pattern and only five coils of the vas deferens. The tropical L. aciculus is distinguished by its fewer (seven) coils of the vas deferens, larger spicules (some with bifid rays) and the lack of the quilted pattern on the surface of the colony.

Leptoclinides placidus Kott, 2001

Leptoclinides placidus Kott, 2001: 75 .

Distribution. Previously recorded (see Kott, 2001): New South Wales (Solitary Is) to Queensland (Hervey Bay). New records: New South Wales (Byron Bay, QM G308514-5).

Description. As previously described, the stellate spicules, to 0.06 mm in diameter, have 9–11 rays with chisel-shaped tips in optical transverse section and are crowded throughout the tough, hard colonies. The common cloacal cavities are oesophageal; the vas deferens coils seven times around the circle of four or five long, club-shaped male follicles.

Figures

FIG. 2. Leptoclinides decoratus (SAM E3214). (A) Thorax; (B) abdomen. Scale bars: 0.1 mm.

FIG. 15. (A) Atriolum glauerti (WAM 141.93); (B) Leptoclinides aciculus (QM 308615); (C) Leptoclinides brandi (QM G308645); (D) Leptoclinides cavernosus (WAM 308.89); (E) Leptoclinides comitus (SAM E3223); (F) Leptoclinides constellatus (QM G308634); (G) Leptoclinides decoratus (SAM E3212); (H) Leptoclinides levitatus (QM G308603).

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).