Aplidium lunacratum

Aplidium lunacratum Kott, 1992

(Figures 6 B, 7)

Aplidium lunacratum Kott, 1992: 558 fig. 86 pl. 14a–c, nom. nov. for Psammaplidium ordinatum Herdman & Riddell, 1913, west and south Australia; Kott 2003, New South Wales.

Stations. TR 6 (MNHN A1 APL.B 551). TR 17 (MNHN A1 APL.B 552). TA 10 (MNHN A1 APL.B 550).

The colonies, up to 10 cm in extent are in hard sandy crusts 0.5 to 2cm thick or in club-shaped lobes. In a same colony the surface varies, the protruding parts show hollows edged by a crest with a honey-combed aspect and some other sectors are flat (Fig. 6 B). The zooid systems are circular, obvious when they are cup-shaped but the zooid apertures are hardly visible among the sand coating. The thoraces of the zooids are perpendicular to the colony surface and the long post-abdomens are tangled in the sandy tunic. The tubular oral siphon ends in 6 yellow or brown lobes. The atrial siphon is elongated in a tube at the level of the third stigmata row. A pointed or bi-dentate languet is distinctly inserted above the siphon (Fig. 7 C) as figured by Kott (1992 fig. 26C–D). A small round protrusion with dark pigment cells is located behind the siphon. The thoracic musculature is weak with few thin fibres, and the body wall has dark pigment cells in specimens in formalin. There are 10 to 12 rows of 11 stigmata interrupted along the dorsal line and on each side of the endostyle (Fig. 7 A). The stomach has 5 round folds. The postabdomen is thin, sometimes more than 1cm long. The ovary is far from the abdomen and followed by the testis. A single larva is incubated in atrial cavity (Fig. 7 B). The trunk is 0.8mm long. The 3 adhesive papillae are short separated by 2 protrusions. The anterior part of the larva is covered with numerous small ampullae (Fig. 7 B).

A. lunacratum has a wide geographic distribution spread from the southern and western Australia to Madagascar.