The 'petaltail' dragonflies (Odonata: Petaluridae): Mesozoic habitat specialists that survive to the modern day

Wednesday, November 13, 2013: 9:26 AM
Meeting Room 4 ABC (Austin Convention Center)
Christopher Beatty , Department of Biology, Santa Clara University, Santa Clara, CA
Jessica L. Ware , Department of Biological Sciences, Rutgers, The State University of New Jersey, Newark, NJ
Dragonflies are an ancient group of organisms, appearing in the fossil record for the last 325 million years; however, individual dragonfly species—like other arthropod species—are thought to persist only for ~10 million years.  Here we report results suggesting that the species of one family—Petaluridae—are very much older.  The eleven extant petalurids are found in Australia, New Zealand, Chile, Japan and North America.  Through a Bayesian molecular phylogeny and BEAST relaxed molecular clock, we show that the petalurids originated ~160 million years ago, and that many of these species have persisted as independent lineages for ~70 million years.  Analysis with LaGrange suggests that these species distributed along the coast of the supercontinent Pangaea, arriving at their current locations through continental drift.  These long species ‘lifespans’ are surprising, especially for a group of habitat specialists with long development times (petalurid larvae live exclusively in fen habitats, and take several years to reach adulthood).  As such these dragonflies challenge our understanding of the factors that drive extinction.