Out of Australia: Belloliva (Neogastropoda: Olividae) in the Coral Sea and New Caledonia

Abstract

The genus Belloliva (Gastropoda: Olividae) consists of small (<15 mm) operculate species and was hitherto thought to be essentially confined to coastal waters of southern and eastern Australia. We report a small radiation from deep water (100–1000 m) in the Coral Sea and New Caledonia, consisting essentially of undescribed species. The new genus Calyptoliva, which differs from Belloliva by the absence of a mantle filament and the presence of a mantle lobe, is also represented in the same area by new species. Based on correlation with shell characters, we suggest that the olivid mantle lobe is responsible for secreting the primary spire callus that overlies the suture, rather than producing the columellar callus as was previously believed (Marcus and Marcus 1959). Belloliva and Calyptoliva combine a suite of shell, radular, and anatomical characters that is shared with either the Olivinae or the Ancillariinae. This raises the question of the distinctiveness of the two classically recognized subfamilies within the family Olividae. All species have paucispiral protoconchs with inferred limited larval dispersal, and many have extremely narrow distributions, sometimes endemic to a single guyot, or they show discrete geographical differentiation. New species: Belloliva iota sp. nov., Belloliva alaos sp. nov., Belloliva apoma sp. nov., Belloliva ellenae sp. nov., Belloliva obeon sp. nov., Belloliva dorcas sp. nov., Calyptoliva bolis gen. nov., sp. nov., Calyptoliva amblys sp. nov., Calyptoliva tatyanae sp. nov.