Trididemnum pigmentatum Kott, 2001

Kott, Patricia, 2007, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part 4), Journal of Natural History 41 (17 - 20), pp. 1163-1211 : 1196-1203

Trididemnum pigmentatum Kott, 2001

( Figure 11A ) Trididemnum pigmentatum Kott 2001, p 278 and synonymy; 2005a, p 2457 and synonymy.

Distribution

Previously recorded (see Kott 2005a): Western Australia (Kimberly, Montebello Is); Queensland (Hervey Bay-Lizard I.); Northern Territory (Bynoe Harbour, Darwin); West Pacific ( Indonesia, Fiji). New records: Queensland (Great Barrier Reef: 14.715 ° S, 145.405 ° E, 26 m, QM G308842 ; 17.645 ° S, 146.375 ° E, 27 m, QM G308897 ; 17.935 ° S, 146.785 ° E, 35 m, QM G308840 ; 18.615 ° S, 146.645 ° E, 30 m, QM G308841 ; 17.865 ° S, 146.645 ° E, 66 m, QM G308844 ; 18.015 ° S, 146.295 ° E, 25 m, QM G308893 ; 17.645 ° S, 146.375 ° E, 27 m, QM G308898 ) .

Description

Small, lumpy three-dimensional scraps of colony, with the largest containing zooids with eight coils of the vas deferens around an undivided testis.

The spicules are large, stellate, to 0.15 mm diameter with 11–15 long attenuated rays with very pointed tips. Spicules are present throughout the colony but are most crowded at the surface. Zooids are covered with dark squamous epithelial cells. They have the usual short posteriorly orientated siphon, about 10 rows of stigmata, and eight coils of the vas deferens. Remarks

The specimens are assigned to this species on the basis of the large stellate spicules with numerous long, attenuated, pointed rays. Dark squamous epithelium and eight coils of the vas deferens are also characteristic of the species, which has not been reported outside tropical waters.

Trididemnum sibogae has smaller spicules and more complex colonies than the present species. Trididemnum titanium sp. nov. has larger spicules (to 0.17 mm diameter), but they have fewer spicule rays than the present species.

Figures

Figure 11. Scanning electron micrographs. (A) Trididemnum pigmentatum (QMG308842); (B) Trididemnum sibogae (QM G308893); (C) Trididemnum titanium (QM G308816); (D) Lissoclinum capsulatum (QM G308804); (E) Lissoclinum reginum (QM G308871); (F) Didemnidae?genus?species (QM G308889); (G, H) Didemnidae?genus?species [(G) QM G308888; (H) QM G308900].