Meeting Abstract

97.3  Thursday, Jan. 7  Evolution of box jellyfishes (Cnidaria: Cubozoa) BENTLAGE, B*; CARTWRIGHT, P; COLLINS, A G; University of Kansas bentlage@ku.edu

Cubozoa (Cnidaria: Medusozoa) represents a small clade of approximately fifty described species, some of which are highly toxic, causing serious human envenomations. Our understanding of the evolutionary history of Cubozoa has been limited by the lack of a sound phylogenetic hypothesis for the group. As part of the Cnidarian Tree of Life project we assembled a comprehensive cubozoan phylogeny. This phylogeny has the potential to further our understanding of cubozoan venom evolution, biogeography and life history evolution. In particular, the phylogenetic hypothesis we present suggests that: 1) the poorly understood mechanisms that can cause a severe medical condition (Irukandji syndrome) caused by several box jellyfish species arose early in cubozoan evolution, 2) deep divergences between Atlantic and Indo-Pacific clades may be explained by ancient vicariant events and 3) sexual dimorphism evolved a single time in concert with complex sexual behaviour. In addition, cubozoan species identities have long been misunderstood and our data support many of the recent scientific descriptions of cubozoan species. However, a phylogeographic analysis of Alatina spp. from the Pacific reveals that at least two species in this genus represent artificial taxonomic units, highlighting the need for integrating molecular techniques with more traditional taxonomic methods in order to understand species’ identities.