REVSYS: Revisionary Systematics of Hawaiian Mecyclothorax Beetles (Coleoptera: Carabidae)

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A grant has been awarded to Dr. James Liebherr at Cornell University to taxonomically revise Hawaiian carabid beetle species in the genus Mecyclothorax. This group demonstrates extremely rapid speciation; current estimates suggest that the nearly 200 species have evolved from a single ancestor that colonized either Maui or Molokai less than 2 million years ago, a speciation rate 16-40 times more rapid that related mainland species. More than half of these species are undescribed, many having been newly collected by the PI and colleagues during field work over the past 12 years. Two field expeditions to five previously unstudied wet-forest areas will improve geographic coverage for species sampling of the group. Morphological characters will be studied in order to produce a phylogenetic hypothesis of the species. The analysis will include numerous Mecyclothorax species from across the southwest Pacific Ocean, allowing the source for the Hawaiian radiation to be discovered. This hypothesis will serve as the framework within which evolutionary forces driving rapid speciation will be studied. These characters will also form the basis for identification keys-both web-based and print-published-that will enable scientists and resource managers to identify individual specimens.Because Mecyclothorax species exhibit habitat specificity-e.g., restriction to particular plant species, microhabitats, or life zones-accurate identification will enhance the ability to monitor such ecological situations in the face of ever-increasing alien species introductions. The PI will compare phylogenetic patterns in Mecyclothorax with those in an independent Hawaiian carabid beetle radiation-the 131-species of Blackburnia-to test the validity of the cladistic biogeographic paradigm. Known ages of the Hawaiian Islands provide powerful chronological constraints in this test, making the Hawaiian system an ideal venue for carrying out this investigation. The phylogenetic hypothesis will also permit elucidation of how ecological preferences have changed during evolution of this radiation.