Meeting Abstract
It is crucial to expand our understanding of marine biodiversity as evidence of a terrestrial biodiversity crisis mounts and similar challenges are imposed on marine systems. In the wake of the Deepwater Horizon oil spill in the Gulf of Mexico, surveys documenting the makeup of benthic communities noted changes in the health and diversity of decapod crustaceans at repeatedly sampled sites, suggesting that such diversity may be an important indicator of ecosystem health. Among decapods, hermit crabs may be especially sensitive to environmental fluctuations because their reliance on abandoned snail shells for shelter creates a complex dependence on a functioning ecosystem. Drawing on extensive museum collections at the National University of Singapore and the University of Louisiana, Lafayette, DNA sequences were used to infer a maximum likelihood phylogeny for the genera Paguristes and Areopaguristes. This subset of hermit crabs is known for high levels of cryptic diversity worldwide, allowing comparisons of species diversity across contrasting habitats and environmental gradients. Results presented here confirm the presence of previously unacknowledged species in the western Atlantic, and preliminary evidence suggests a similar situation in the western Pacific. Results also refute morphologically based hypotheses that both target genera are monophyletic. This discord between morphological and molecular data warrants reassessment of the phylogenetic signal in ostensibly diagnostic morphological characters, while also providing a molecularly based template for inference of evolutionary processes. Knowledge of hermit crab biology superimposed on a robust molecular phylogeny can yield testable hypotheses about the nature of hermit crab biodiversity to further inform environmental and biogeographic studies.
