MURICIDAE, Rafinesque, 1815

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 : 2493

Family MURICIDAE

Thais species

The recent history, occurrence, and distribution of a number of species of muricids along the South African coast remain to be investigated. On the one hand, we are compelled by the evidence that a number of Indo-Pacific Thais have been and are being transported by human means. Both Thais sacellum and Thais lacera have been introduced to the Mediterranean ( Gofas and Zenetos 2003; Singer 2005) and Thais blanfordi has been found being transported long distances in ships’ sea chests ( Richards 1990). On the other hand, it is not clear if some western Indian Ocean muricids naturally find their southernmost distributions extending to Mozambique, South Africa or Madagascar. Another layer of complexity is that we further expect that more northern species may now be extending their ranges south with coastal warming.

We treat two species, Thais blanfordi and Thais tissoti as introductions. In addition, Thais lacera ( Kilburn and Rippey 1982) , Stramonita haemastoma ( Kilburn and Rippey 1982 as Thais haemastoma ), Thais aculeata ( Steyn and Lussi 1998) and Thais sacellum (G. Branch, personal communication, 2009), have all been reported from South African coasts, but their distribution and current status require further study.

Thais blanfordi (Melvill, 1893) Introduced

We tentatively admit this well-known muricid as a non-native species because of its apparent historical absence from South Africa, combined with its known association with shipping. Kilburn and Rippey (1982) noted its presence on the east coast in Durban Bay with the compelling observation that it had not been reported in Natal “until a few decades ago,” speculating that it “may originally have been introduced into Durban Bay on the hulls of ships.” Tan and Sigurdsson (1996), in a review of several Thais species from the Indian Ocean, noted that Thais blanfordi was restricted to the western half of the Indian Ocean, and cited material from India, Kenya, Madagascar, Mozambique and Pakistan. Within the same review, South African specimens were cited from Delagoa and Durban Bay. This snail was first collected in South Africa in 1950 and we consider ship fouling and ballast water to be the likely vectors.

Thais tissoti (Petit, 1852) Introduced

As with Thais blanfordi, Kilburn and Rippey (1982) remarked on the historical absence of this species in Durban Bay, and suggested ship-mediated introduction. Tan and Sigurdsson (1996) note that it appears to be restricted to the Indian west coast, Sri Lanka and the African east coast, specifically reporting material from India, Mozambique, Oman, Pakistan, Sri Lanka and Thailand. Within this review South African specimens were cited from Durban and Thompson’s Bay on the east coast. The first collection date was 1950 and we also consider ship fouling and ballast water to be the likely vectors for this species.