Distribution: Few SA records. SA coastal waters from Coffin Bay to Cape Jervis and northern Kangaroo Island
Habitat: Rocky areas and reef under rocks
Depth: Lower intertidal and shallow subtidal
This cushion-shaped colonial ascidian has sand embedded in its mostly-transparent greyish test. It has roughly circular systems around common cloacal apertures. Both the branchial apertures and the larger cloacal openings are black-rimmed. This species is similar to Aplidium lunacratum, but that species is much larger, has opaque black colouration and is found in exposed locations, while S. sphinctorum is usually found under rocks or otherwise sheltered locations (such as tidepools).
