Meeting Abstract

24.3  Wednesday, Jan. 5  Patterns of speciation in sea cucumbers MICHONNEAU, Francois; University of Florida francois.michonneau@gmail.com

Despite their striking presence on coral reefs and the multi-millon dollar industry targeting them, aspidochirotid holothurians have received relatively little taxonomic attention. Heavy reliance on ossicles has lead to a confused taxonomy and masks substantial cryptic diversity. As part of revisionary effort on holothurians, we are sequencing multiple specimens of available species to test for species limits and construct phylogenetic hypotheses. We are using a bottom-up approach, sequencing fast-evolving mitochondrial markers (16S and COI) first, as these are mostly informative at lower taxonomic levels. We have unraveled many species complexes and identified several undescribed species. For instance, our analyses revealed that the circumtropical “species” Holothuria impatiens consist of at least a dozen reciprocally monophyletic, well-defined, evolutionary significant units (ESUs). Broad overlap in the range of some, in combination with recent divergence indicate the rapid evolution of reproductive isolating barriers among these ESUs. Such rapid evolution to sympatric coexistence is also found in several other species complexes of sea cucumbers we identified, and contrasts with many groups of marine invertebrates.