Eudistoma amplum (Sluiter, 1909)

KOTT, PATRICIA, 2003, New syntheses and new species in the Australian Ascidiacea, Journal of Natural History 37 (13), pp. 1611-1653 : 1624

Eudistoma amplum (Sluiter, 1909) Polycitor amplus Sluiter, 1909: 21 ; Kott, 1990a: 194 and synonymy; Monniot and Monniot, 1996: 185.

Distribution. New records: Queensland (Swain Reefs, QM G305762; Lihou Reef, QM G306995). The species is known from the Great Barrier Reef, Micronesia, Indonesia, Palau Is, Papua New Guinea and the Philippines (see Kott, 1990a).

Description. The colony from Lihou Reef is a robust irregular plate about 1 cm thick, with circular systems of about six zooids, each with a long atrial opening into a small common cloacal cavity in the centre of the circle. Sand and brown pigment are in the lower half of the colony which also contains the zooids which are withdrawn from the surface in the specimen.

Remarks. The presence of a shallow common cloaca with a central aperture rather than a shallow depression in the surface (as is usually reported for this species) has also been reported by Millar (1975) for one of the colonies from Toeal. This type of colony resembles E. reginum Kott, 1990a in its true common cloacal cavity, although it lacks the hard test and large red vesicles of the latter species.