Leptoclinides grandistellus, Kott, 2004

Kott, Patricia, 2004, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part I), Journal of Natural History 38 (19), pp. 731-774 : 735-737

Leptoclinides grandistellus sp. nov.

( figure 2 )

Distribution. Type locality: Western Australia (about 35 km SW of Cliff Head Dongara, 29 ° 4 ∞ S, 114 ° 42.5 ∞ E, 44 m on rock and weed, MV Sprightly dredging cruise Stn, 17 m, 17 February 1976, holotype WAM Z10920 ).

Description. The colony has firm translucent test with evenly distributed but not especially crowded spicules in the surface, making it raspy. Spicules become slightly less crowded toward the base of the colony. The spicules are large (to 0.22 mm in diameter), stellate, with 9–11 conical, pointed or chisel-shaped rays in optical transverse section. The common cloacal cavity is large and posterior abdominal. Zooids are large, attached firmly in the test and impossible to remove. Branchial and atrial siphons are long, with strong circular muscles around them. Four fine longitudinal muscles are in the parietal body wall on each side of the thorax. The branchial tentacles project up into a chamber at the base of the branchial siphon. Fourteen stigmata are in the anterior row of four in the branchial sac. The gut loop is horizontal behind the thorax. Gonads were not detected. Larvae are not known.

Remarks. The species is distinguished from other Leptoclinides by its large spicules. Leptoclinides magnistellus Kott, 2001 from Tasmania has spicules up to 0.24 mm diameter, but they have more rays in optical transverse section (11–13) and are crowded throughout, making the colony hard and brittle rather than tough and gelatinous like the present species.

Leptoclinides seminudus Kott, 2001 Leptoclinides seminudus Kott, 2001:82 .

Distribution. New records: New South Wales (Coffs Harbour jetty piles, 0–5 m, MV F53283 ); Tasmania (Tasman Peninsula, SAM E2928). Previously recorded (see Kott, 2001): South Australia (St Vincent Gulf), Victoria (Western Port), Tasmania (King I.).

Description. Colonies form robust, tough (but never hard or brittle) sheets with randomly placed common cloacal openings on elevations of the surface. In preservative the colonies are pinkish brown or beige. Branchial apertures are evenly spaced. Secondary common cloacal canals are oesophageal although the primary canals extend the full length of the zooids and extend into posterior abdominal cavities. A thin spicule-free layer of test is on the surface and another of variable thickness (never more than one-third of the thickness of the colony) is on the base of the colony. Elsewhere spicules are evenly distributed, though not very crowded. The newly recorded colony from Coff ’s Harbour has ridges up to 1 cm high, sometimes forming flat lamellae with deep furrows between them where the colony is only 5 mm thick. In the high ridges, deep primary canals surround clumps of zooids and separate them from a central test core. Common cloacal apertures are on the high parts of the ridges. Spicules are stellate, to 0.086 mm diameter, with 7–11 rays in optical transverse section, the rays with rounded, truncated or chisel-shaped tips.

Zooids are impossible to remove from the colony. They have a long atrial siphon with conspicuous circular muscles, large thoraces with 12 stigmata in the anterior row, a simple vertical gut loop and nine coils of the vas deferens around a cluster of up to seven or eight testis follicles. A large circular lateral organ is on each side of the posterior third of the thorax.

Remarks. As in the type material, preserved colonies are some shade of brownish or pinkish beige, branchial apertures are evenly distributed, randomly distributed common cloacal apertures are on only slight elevations of the surface and the spicules occasionally have chisel-shaped rays. The lack of a quilted pattern on the surface distinguishes the species from others with similar spicules. Leptoclinides placidus Kott, 2001 resembles the present species in its smooth surface without depressions over primary common cloacal canals, but it has extensive posterior abdominal cloacal cavities, spicules throughout the test and seven coils of the vas deferens. Although Kott (2001) reported eight coils of the vas deferens, nine (as in Kott, 2001: figure 37c) have been found on re-examination of the material. This is an unusually large number for this genus, and, with the different cloacal systems, helps to distinguish the species from Leptoclinides maculatus (with eight coils of the vas deferens).

The high surface ridges reported from the Coff ’s Harbour specimen could be a response to its habitat on vertical wharf piles.

The new records of this species constitute extensions to the northern and southern limits of its known geographic range.

Figures

FIG. 2. Leptoclinides grandistellus (WAM Z10920): (A) vertical section through colony; (B) zooid; (C) spicules. Scales: (A) 1.0 mm; (B) 0.1 mm.