Marine Biology

, Volume 161, Issue 4, pp 899–910

Afro-Eurasia and the Americas present barriers to gene flow for the cosmopolitan neustonic nudibranch Glaucus atlanticus

  • Celia K. C. Churchill
  • Ángel Valdés
  • Diarmaid Ó Foighil
Original Paper

DOI: 10.1007/s00227-014-2389-7

Cite this article as:
Churchill, C.K.C., Valdés, Á. & Ó Foighil, D. Mar Biol (2014) 161: 899. doi:10.1007/s00227-014-2389-7

Abstract

Pelagic species have been traditionally thought to occupy vast, genetically interconnected, geographic ranges in an essentially homogeneous environment. Although this view has been challenged recently for some mesopelagic planktonic taxa, the population structure of hyponeustonic (surface-drifting) species remains unknown. Here, we test the hypothesis of panmixis in Glaucus atlanticus, a cosmopolitan neustonic nudibranch, by assessing the genetic differentiation of multiple representatives from a global neustonic sampling effort. Specimens were collected from all subtropical oceanic gyre systems (North Atlantic, South Atlantic, North Pacific, South Pacific, and Indian Ocean). We sequenced a fragment of the mitochondrial cytochrome oxidase I gene for 98 individuals and performed population structure, differentiation (analysis of molecular variance, spatial analysis of molecular variance, FST, Jost’s D), and molecular clock analyses. Our results indicate that G. atlanticus is not globally panmictic, but that populations appear to be panmictic within ocean basins. We detected several topologically ectopic haplotypes in the Atlantic Ocean, but the molecular clock analysis indicates that these have diverged from closely related Indo-Pacific haplotypes over 1.2 MYA, coinciding with cooling in waters around in the southern tip of Africa and resulting oceanographic changes. These data and the fact that G. atlanticus is not known from polar latitudes suggest that gene flow between ocean basins is hindered by physical barriers (supercontinents) and water temperatures in the Arctic and Southern Oceans.

Supplementary material

227_2014_2389_MOESM1_ESM.docx (343 kb)
Appendix S1 Bayesian maximum credibility tree (DOCX 343 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Celia K. C. Churchill
    • 1
    • 2
  • Ángel Valdés
    • 3
  • Diarmaid Ó Foighil
    • 1
  1. 1.Museum of Zoology and Department of Ecology and Evolutionary BiologyUniversity of MichiganAnn ArborUSA
  2. 2.Marine Science InstituteUniversity of California, Santa BarbaraSanta BarbaraUSA
  3. 3.Department of Biological SciencesCalifornia State Polytechnic UniversityPomonaUSA