Aplidium crateriferum ( Sluiter, 1909 )

Monniot, Françoise & Monniot, Claude, 2001, Ascidians from the tropical western Pacific, Zoosystema 23 (2), pp. 201-383 : 207

Aplidium crateriferum ( Sluiter, 1909)

Amaroucium crateriferum Sluiter, 1909: 103 . Type locality: Philippines. Synonymy: see Kott 1992a: 536, fig. 71.

MATERIAL EXAMINED. — Philippines. SW Bohol, Panglao Island, 23 m, 20.IV.1997 ( MNHN A1 APL.B 390).

DESCRIPTION

The colonies were attached to gorgonians, as smooth dark grey cushions with orange zooids inside. The tunic is up to 3 cm thick with large furrows between swellings. The zooids are arranged in lines. Some sand is incrusted along the lines of the oral siphons; it is sparse inside the tunic, more abundant in the base of the colony.

The oral siphon is long with short lobes and an apical stout sphincter making a protruding ring. The cloacal aperture is far apart at the level of the fourth stigmata row, in a short tube. A simple languet is inserted distinctly anterior to the aperture. There is a large unperforated area at the anterior part of the branchial sac. The thorax is elongated, with 18 to 20 rows of stigmata. The abdomen contains a long cylindrical stomach with five deep longitudinal folds.

The post-abdomen is particularly long. The ovary lies far from the gut, followed by a double row of testis follicles.

Only immature larvae were found in the cloacal cavity. They are particularly large, 1.9 mm for the trunk. They have three adhesive papillae and an anterior crown of dense ampullae.

REMARKS

The general structure very well corresponds to the type specimen that we examined (ZMA-TU 1278). The oral siphon with a strong sphincter, the cloacal aperture on a short tube, strong muscles in the transverse vessels, numerous rows of stigmata and a long stomach are common characters.

The species distribution comprises the Philippines, Queensland and western Australia.