Large colonies consisting on single or multiple stalked conical to ovoid heads (35 mm long and 12 mm in diameter long distinctive stalk (35 mm long).
Colour vary from white to dark orange.
Zooids open individually on head only.
No sand particles visible on the surface of the head of the colony but sand visible externally on stalk.
Internally sand and / or shell fragments distributed to varying amounts (generally sparsely but occasional more dense).
Zooids (up to 17 mm long) with lobed siphons and branchial sac with 3 rows of stigmata with up to 18 stigmata per row.
Gonads in the long posterior abdomen (1-2 ova with up to 50 male follicles).
Larvae incubated in peribranchial cavity and also found in the test under the test surface.
Larvae with 3 adhesive organs each surrounded by elongated ampullae.
Millar, R. H. 1954 XXI - Pseudodistoma africanum sp. N. A new compound ascidian from South Africa7:128-132
Millar, R. H. 1962 Further descriptions of South African ascidians56:113-221
Monniot, C.; Monniot, F.; Griffiths, C. and Schleyer, M. 2001 Ascidians of South Africa.108:1-141
Shenkar, N.; Gittenberger, A.; Ruis, M.; Rocha, R. M.; Swalla, B.; et al. 2017 Ascidiacea World Database. Atriolum marinense Kott, 2001. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=250052 on 2019-03-12