Aplidium caelestis Monniot, 1987

Kott, Patricia, 2006, Observations on non-didemnid ascidians from Australian waters (1), Journal of Natural History 40 (3 - 4), pp. 169-234: 204-205

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http://doi.org/ 10.1080/00222930600621601

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Aplidium caelestis Monniot, 1987


Aplidium caelestis Monniot, 1987  

Aplidium caelestis Monniot 1987, p 517   . Kott 1992a, p 528 and synonymy.


Previously recorded (see Kott 1992a): Western Australia (Shark Bay, Mullalloo Beach, Rottnest I., Hillary’s Boat Harbour); South Australia (St Vincent Gulf, Spencer Gulf); Victoria (Bass Strait); New South Wales (Norfolk I.); Queensland (Capricorn Group); New Caledonia; Marianas Is. New record: Queensland (south-eastern coast, QM G321403).


The newly recorded specimen is a robust, thick slab overgrowing ascidians and other organisms. Sessile common cloacal apertures occur at the junctions of the long canals that are lines on each side. Sand is crowded in the colony, especially in the ridge that protrudes from the surface between the rows of zooids, although it is absent from the surface over the common cloacal canals. In the preserved specimens oval masses of black granular bodies also are in the test between the rows of zooids. Zooids have pale yellow thoraces, yelloworange abdomina, and white posterior abdomina (with two rows of male follicles). The atrial tongue is well separated from the aperture.


Generally the newly recorded colony resembles those previously described. The sandy test, long double rows of yellowish zooids, dark granular bodies, long narrow zooids with conspicuous siphons, separate atrial tongue and a narrow gut loop with a small five-folded stomach appear to be characteristic.

The geographic range of this species, from Western Pacific tropical locations to Australian temperate waters, is vast. It appears to be one of the species that can be said to use the Australian coast as a bridge between tropical and temperate waters.

Aplidium clivosum Kott, 1992  

( Figure 10F View Figure 10 )

Aplidium clivosum Kott 1992a, p 530   and synonymy.


Previously recorded (see Kott 1992a): Western Australia (from Port Hedland to Hamelin Bay on the south-western coast)   ; South Australia (Great Australian Bight to Nuyts and Eyre Peninsulas, Kangaroo I., Gulf St Vincent)   ; New South Wales ( Jervis Bay ); Queensland (Capricorn Group). New record   : Tasmania ( Forestier Peninsula , 8–15 m, SAM E3390 View Materials )   .


The newly recorded specimen has the characteristic appearance of these large, conspicuous cushion- to tabular-shaped colonies, with a more or less horizontal upper surface where rows of zooids are along each side of common cloacal canals converging to large protuberant common cloacal apertures. Rounded marginal elevations on the upper surface surround each large cloacal system as well as the outside margin of the colony. The sides of the colonies are encrusted with sand, which also is present throughout the test, absent only from around the thoraces along each side of the shallow radial common cloacal canals. The sand can be seen in radial lines intruding in toward the common cloacal apertures between the double rows of zooids.

Zooids are distinctive with conspicuous sphincter muscles, a large atrial lip well removed from the apertures and five gastric folds. Colonies are invariably some shade of pink to red.


Other species with similar systems depressed into the upper surface of the colony and similar zooids with conspicuous siphonal muscles and separate atrial tongues are A. cratiferum ( Sluiter, 1909)   and A. grisiatum Kott, 1998   . The former can only be distinguished by its cloacal systems with the zooids opening around a central cavity rather than along each side of converging canals. The latter can be distinguished only by its more numerous gastric folds. Many of the Aplidium spp.   (see Kott 1992a) have similar zooids to the present species, with conspicuous sphincters, separate atrial apertures and five stomach folds, but they have long, branched or circular common cloacal canals rather than central chambers or cavities or radial canals.

Species in other genera, namely the temperate Aplidiopsis mammillata Kott, 1992a   , and the tropical Synoicum castellatum Kott, 1992a   , also have similar colonies, although the latter has cloacal systems more like A. cratiferum   and both are readily distinguished by their generic characters.

The present species, unlike A. caelestis   , appears to be an indigenous Australian species. It has been recorded from temperate locations more often than from the tropics, although it does extend up both the western and eastern coast of Australia.


South African Museum














Aplidium caelestis Monniot, 1987

Kott, Patricia 2006

Aplidium clivosum

Kott P 1992: 530

Aplidium caelestis

Kott P 1992: 528
Monniot C & Monniot F 1987: 517