This species currently present specimens consisting of single and elaborate compound lobes connected by a common base.
Laterally flattened fan-shaped head (2-3 cm) carried on a long slender stalk (2-4 cm).
Zooids are arranged in double rows on either side of a common cloacal channel opening on the rim of the head.
Colonies are cream, orange, brown, brilliant white or bright blue in colour.
Zooids (1-2 mm in length) with short branchial, and slightly longer atrial siphon or atrial opening with a wide anterior lip.
The branchial sac has 4 rows of stigmata with 12-14 stigmata per row.
Male and female gonads mature at different times.
The male gonad consist of 4 to 6 testes follicles at the base of the intestinal loop.
A brood pouch to contain the developing larvae.
Hartmeyer, R 1912 Die Ascidien der deutschen Tiefsee-Expedition.16:225-392
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