ASCIDIIDAE, Herdman, 1882

Mead, A., Carlton, J. T., Griffiths, C. L. & Rius, M., 2011, Introduced and cryptogenic marine and estuarine species of South Africa, Journal of Natural History 45 (39 - 40), pp. 2463-2524 : 2505

Family ASCIDIIDAE

Ascidia sydneiensis Stimpson, 1855 Introduced

This solitary ascidian can reach up to 100 mm and has a tunic that is often covered by mud and epibionts. It is commonly found on pontoons and jetties, where it lives within a matrix of fouling organisms (M. Rius personal observation). Primo and Vasquez (2004) considered Ascidia sydneiensis as a cosmopolitan species, because of lack of evidence for its origin, however Monniot et al. (2001) consider it a Pacific Ocean species. In South Africa, it was first recorded by Michaelsen (1934) from samples collected in False Bay (southwest coast) in 1932. Since then, it has been found in Port Elizabeth on the southeast coast (M. Rius, unpublished results). It is usually a dominant fouling organism in harbour communities.

Ascidiella aspersa (Müller, 1776) Introduced

The tunic of this abundant European ascidian is semi-transparent and the mantle is normally white with pale red siphons, which make it easily to identify on ropes, tyres and pontoons within harbours (M. Rius, unpublished results). It is now found worldwide ( Monniot et al. 2001). The first South African record was by Monniot et al. (2001) from Table Bay Harbour on the southwest coast.