The Nacellidae split from the Lepetidae plus Pectinodontidae between 98-216 Ma, a period that included the fracturing of Gondwana into western and eastern portions in the late Jurassic (Lawver, Gahagan & Coffin, 1992; Crame, 1999). Our results are consistent with a southern origin for the Nacellidae in the Cretaceous, followed bv the radiation of Nacella in eastern Gondwana (Antarctica and South America), and of Cellana in Antarctica, South America, Australia, New Zealand and the Indo-Pacific. During the Cretaceous, the southern Pacific margin was isolated by the geography of Gondwana and prevail¬ing oceanic circulation, and the Weddellian Province supported a distinctive molluscan fauna (Zinsmeister, 1982; Crame, 1996). Nacellid-like fossils have been found in the Antarctic Peninsula (Stilwell & Zinsmeister, 1992) and New Zealand (Beu, Maxw:ell & Brazier, 1990), but these records are only from the Upper Eocene. Cellana Carpentaria is present in lower Cretaceous deposits in Australia (Powell, 1973), but this fossil has been not been investigated for shell microstructure so its familial placement is unclear. Between the Upper Cretaceous and the early Cenozoic, the temperate Weddellian molluscan fauna extended from Patagonia to Australia (Stilwell & Zinsmeister, 1992, 2000; Zinsmeister, 1982). The basal placement of the New Zealand Cellana also implies that it likely had a palaeoaus-tral origin. All the available evidence suggests that Cellana accomplished its radiation in the tropical Indo-Pacific during the Neogene.