Leptoclinides fungiformis Kott, 1972

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 : 1168-1169

Leptoclinides fungiformis Kott, 1972

( Figures 12B–D ; 16C )

Leptoclinides fungiformis Kott 1972, p. 180 ; 2001, p. 63.

Distribution

Previously recorded (see Kott 2001): South Australia (Pearson I., Investigator Strait); New record: Western Australia CSIRO SS10 / 05 (Point D’ Entrecasteaux, Stn 18, 100 m, 21.11.05, QM G328444 ; Albany, Stn 22, 100 m, 22.11.05, QM G328105-6 ) .

Description

The newly recorded colonies are large, robust vertical bulb-shaped lobes, about 4– 7 cm diameter at the top and narrowing (to about 2–3 cm) toward the base. The upper surface is rounded, although the whole surface of the upper expanded half of one colony (QM G328105) projects out into three long, vertical, rounded vanes or ridges. The narrow, constricted basal part of the colony does not form a distinct cylindrical stalk as reported previously for this species, although it does expand into a holdfast at the base. Spicules are crowded in the surface which is smooth and hard. Internally spicules are absent from the test at the abdominal level, although they are present and evenly spaced through the remainder of the test, albeit not crowded as they are in the surface. Posterior abdominal cavities separate the surface zooidbearing test from the internal test core. A series of dimple-like depressions across the top of the colony may be common cloacal apertures, although they are obscured by the contracted condition of the colony. The small spicules (to 0.042 mm diameter) mostly are stellate with 13–15 short pointed conical rays, although other spicules are almost globular with rounded or flattened ray tips.

Zooids are small and, in the newly recorded material, contracted. The branchial siphon is usually a moderately long cylinder. The posteriorly orientated atrial siphon projecting from the postero-dorsal corner of the thorax is short and the rim of the aperture has minute crenulations. Four rows of up to 14 stigmata are in a half row in the branchial sac. A circle of six or seven wedge-shaped tapered male follicles converge to the vas deferens which make four loose spiral turns around the testis before extending anteriorly to the atrial siphon. A single ovum is between the two outer coils of the vas deferens. Larvae, present in the central test of several of the colonies (QM G328105, G328444), have an almost spherical trunk 0.8 mm diameter with the tail wound the whole way around it. Four rounded lateral ampullae are on each side of the antero-median adhesive organs.

Remarks

The well defined, transversely wrinkled cylindrical stalk and small spicules (to 0.02 mm diameter) that Kott (2001) reported for the South Australian specimens are conspicuously different from the newly recorded material. Otherwise the colonies, especially the consistency of the test, the form and distribution of the stellate spicules and the zooids are the same in all the specimens here assigned to this species. It is possible that in the previously recorded material some environmental factor has favoured the development of a long stalk and Kott (2001) could have overlooked the larger spicules. Nevertheless in due course these differences may be found to be consistent, justifying the definition of two species

The present colonies resemble those of Polysyncraton pedunculatum , especially in regard to their external shape and the position of the common cloacal apertures. The loosely coiled vas deferens (see Kott 2005a) and the presence of the ovum inside the distal coil also resemble Polysyncraton spp. However, the atrial siphon of the present colonies clearly indicates their status as species of the genus Leptoclinides . Leptoclinides minimus Kott, 2005 from Cockburn Sound (Western Australia) has similar small zooids with loosely coiled vasa deferentia. Although re-examination of scanning electron micrographs from the syntypes shows spicules up to 0.036 mm diameter, consistent with the spicules of the newly recorded colonies, L. minimus spicules are distinguished by their more numerous rays.

Figures

Figure 12. Atriolum tubiporum (QM G328004): A, colony. Leptoclinides fungiformis: B1,2 (QM G328106, QM G328105), colonies; C (QM G328105), zooid; D (QM G328105); larva Leptoclinides multilobatus (QM G328128): E, abdomen showing gut loop and gonads. Scales: A, 1.0 cm; B, 2.0 cm; C, 0.1 mm; D, E, 0.2 mm.

Figure 16. Scanning electron micrographs of didemnid spicules: A, Atriolum tubiporum, QM G328004; B, Leptoclinides durus, QM G328158; C, Leptoclinides fungiformis, QM G328444; D, Leptoclinides vesica, QM G328458; E, F, Polysyncraton calculum, QM G328140; G, Polysyncraton dealbatum, QM G328119; H, Polysyncraton fistulum, QM G328446.