Leptoclinides decoratus Kott, 2004b

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 : 2417-2418

Leptoclinides decoratus Kott, 2004b

( Figures 14A , 18A ) Leptoclinides decoratus Kott 2004b, p 2469 and synonymy.

Distribution

Previously recorded (see Kott 2004b): South Australia (Kangaroo I.). New records: South Australia (Kangaroo I., SAM E3257 ) .

Description

The newly recorded colony is a tough, gelatinous slab. Spicules crowded into white spots, and aggregations of black pigment particles crowded into similar-sized black spots are evenly spaced in the surface test. A sparse layer of spicules lines the common cloacal cavity but both spicules and pigment are not in the lower half of the colony, which is separated from the upper zooid-bearing half by vast posterior abdominal common cloacal cavities. Large common cloacal apertures with white spicule-filled rims are terminal on elevated lobes, including short vertical cylinders, produced from the upper surface of the colony. Each of these common cloacal apertures opens from a spacious cavity that connects with the posterior abdominal spaces. Spicules are stellate, to 0.06 mm diameter with seven to nine short rays in optical transverse section, the rays with sharp chisel-shaped or pointed tips.

Remarks

Although the lobes on the surface of the colony often are cylindrical as in some species of the genus Atriolum , the present species does not have the long atrial siphon opening directly into a central cavity as in the latter genus. The species appears to be a southern Australian one, at present known only from Kangaroo I., characterized by its relatively small spicules with few rays which have chisel-shaped and conical tips. The spicules are gathered into small clumps in the surface layer of test where they are mixed with equal-sized clumps of black pigment. Spicules are also in a sparse layer lining the large common cloacal spaces. In life, the colonies look the same as they do in preservative and the in situ photographs, and the newly recorded colony and type material are similar. The appearance of these colonies is distinctive.

Leptoclinides compactus has bulky colonies with rounded lobes with terminal common cloacal apertures, similar spicules (but with more rays) and although the spicules have a similar distribution as in the present species, they form a continuous layer beneath the superficial bladder cell layer rather than being gathered into small clumps.

Figures

Figure 14. Scanning electron micrographs of the calcareous spicules of: (A) Leptoclinides decoratus (SAM E3257); (B) Leptoclinides dubius (WAM 1093.89); (C) Leptoclinides frustus sp. nov. (SAM E3255, holotype); (D) Leptoclinides kingi (WAM Z20557); (E) Leptoclinides minimus sp. nov. (WAM 30.84, holotype); (F) Leptoclinides pulvinus sp. nov. (QM G308742, holotype); (G) Polysyncraton galaxum (SAM E3250); (H) Polysyncraton glaucum (QM G308736).

Figure 18. In situ images of: (A) Leptoclinides decoratus (SAM E3257); (B) Leptoclinides frustus (SAM E3255, holotype); (C) Leptoclinides imperfectus (SAM E3243); (D) Leptoclinides lissus QM G308709); (E) Leptoclinides rigidus (QM G308708); (F) Leptoclinides seminudus (SAM E3264); (G) Polysyncraton cuculliferum (QM G308715); (H) Polysyncraton galaxum (SAM E3261).