MEYER, Christopher P.*; KOHN, Alan J.; University of Washington and Univ. of Florida; University of Washington: Disparate evolutionary trajectories in two hyperdiverse tropical marine gastropod genera

In tropical seas, coral reef-associated environments support maximal benthic biodiversity. Hyperdiverse genera (containing 100->500 species) in several animal groups contribute importantly to the high species diversity. We are investigating whether the evolutionary trajectories of modern hyperdiverse taxa share common patterns of radiation in time and space, based on phylogenetic comparisons. We compare and contrast evolutionary diversification patterns in two such genera of prosobranch gastropod molluscs, Cypraea, in the Order Neotaenioglossa, and Conus, in the Order Neogastropoda. Conus is considered to have about twice as many extant species as Cypraea, and both genera are presently most diverse in the Indo-West Pacific region, but regional patterns of diversity differ strikingly. Both genera have good fossil records that begin contemporaneously about 55 mybp. However, the Cypraea fossil record is preceded by an earlier Mesozoic stem lineage of the Family Cypraeidae, while the ancestor of Conus is uncertain but most likely in the family Turridae. Gene sequence data are available for most Cypraea species and for about one-third of Conus species. They support a prior morphology-based phylogeny of Cypraea, while for Conus they have generated the first species-level phylogenetic hypothesis. Using data from traditional taxonomic treatments, comparative morphology, paleontology, and molecular genetics, we explore the geography, tempo and mode of their radiations, and whether independent clades attained hyperdiversity by similar evolutionary processes.