Meeting Abstract

S8.7  Wednesday, Jan. 6  Evolution of ontogeny in the Hydractiniidae: Losing jellyfish and committing to the colony stage CUNNINGHAM, Clifford W*; MIGLIETTA, MariaPia; BUSS, Leo W; Duke University; Pennsylvania State University; Yale University cliff@duke.edu

We use a multi-gene phylogeny to study heterochrony and evolutionary variation in the pelagic sexual medusa (jellyfish) and benthic asexual (colony) stages of the hydrozoan family Hydractiniidae. This family shows nearly all the life cycle diversity of the Class Hydrozoa, with a great variety of colony forms, and well-established model organisms such as Podocoryna carnea or Hydractinia echinata. Using a multi-gene phylogeny of the Hydractiniidae, we study the evolution the ontogeny of the jellyfish stage, which is repeatedly lost through progenesis. This loss of the free-living jellyfish stage is correlated with predictable changes in colony morphology, and with the range of host-specificity. We conclude by asking whether a free-living jellyfish can be regained after it has been lost for a hundred million years or more, with reference to Dollo’s law.