ARBACIIDAE, Gray, 1855

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 : 2501

Family ARBACIIDAE

Tetrapygus niger (Molina, 1782) Introduced

This “black sea urchin” actually has a distinctive purple test, unlike any other species of urchin found in South Africa. Native to the west coast of South America from Peru to Chile, its presence in South Africa represents the first record of introduction for this species, globally. It was first collected by us during a survey of the Alexander Bay oyster dams in 2007 ( Haupt et al. 2010a). During the survey, a breeding population, composed of both adults and juveniles, was recorded. Tetrapygus niger is the most abundant urchin along the Chilean coast ( Rodriguez and Ojeda 1993). It is a wellknown ecosystem engineer that is both an economic and ecological pest in its areas of origin, because of its grazing impact upon species of kelp ( Vasquez and Santelices 1990; Vasquez and Buschmann 1997; Rodriguez 2003; Vega et al. 2005). We consider the most probable vector to have been import with the Crassostrea gigas spat, for mariculture purposes.