A revision of the Australian fossil species of zoila (Gastropoda: Cypraeidae)

Abstract

Zoila Jousseaume, 1884 is a cowry genus, the species of which are now confined to the coastal waters of Western Australia and southern Australia. Six fossil species are known from southeast Australia, of which three are new, ranging in age from late Oligocene to middle Miocene, known from the Murray, Otway and Bass basins. Three fossil species are known from Western Australia, of which three are new, ranging in age from late Eocene to late Pliocene, known from the Carnarvon, Bremer and Eucla basins. Umbilia (Gigantocypraea) Schilder 1927 (type species Cypraea gigas McCoy) is regarded as a synonym of Zoila. The earliest record of the genus is Z. chathamensis (Cernohorsky, 1971), Paleocene/early Eocene, Chatham Islands, probably ancestral to the Australian fossils. Zoila is closely related to Cypraeorbis Conrad, 1865, of which Bernaya Jousseaume, 1884 is regarded as a synonym. Living species are known to have no planktotrophic larval stage, so there is considerable variation in species morphology. Such direct development arose in these cowries at least as early as the late Eocene. Fossils described here are Zoila viathomsoni sp. nov., Z. didymorhyncha sp. nov., Z.glomerabilis sp. nov., Z. dolichorhyncha sp. nov., Z. mulderi (Tate, 1892), Z. platypyga (McCoy, 1876) (= consobrina McCoy, toxorhyncha Tate, platypyga simplicior Schilder), Z. gigas (McCoy, 1867) (= dorsata, gabrieli), Z. campestris n. sp. and Z. fodinata n. sp.