Contrasting phylogeographic pattern among Eudyptes penguins around the Southern Ocean

A Steinfurth,P Pistorius,M V Petry,K Pütz,N A Lois,D Noll,E Poulin,A Lowther,B Ramos,P Trathan,M J Frugone,G P M Dantas,J A Vianna,F Bonadonna,A Raya Rey,A Polanowski,B Wienecke

doi:10.1038/s41598-018-35975-3

Abstract

Since at least the middle-Miocene, the Antarctic Polar Front (APF) and the Subtropical Front (STF) appear to have been the main drivers of diversification of marine biota in the Southern Ocean. However, highly migratory marine birds and mammals challenge this paradigm and the importance of oceanographic barriers. Eudyptes penguins range from the Antarctic Peninsula to subantarctic islands and some of the southernmost subtropical islands. Because of recent diversification, the number of species remains uncertain. Here we analyze two mtDNA (HVRI, COI) and two nuclear (ODC, AK1) markers from 13 locations of five putative Eudyptes species: rockhopper (E. filholi, E. chrysocome, and E. moseleyi), macaroni (E. chrysolophus) and royal penguins (E. schlegeli). Our results show a strong phylogeographic structure among rockhopper penguins from South America, subantarctic and subtropical islands supporting the recognition of three separated species of rockhopper penguins. Although genetic divergence was neither observed among macaroni penguins from the Antarctic Peninsula and sub-Antarctic islands nor between macaroni and royal penguins, population genetic analyses revealed population genetic structure in both cases. We suggest that the APF and STF can act as barriers for these species. While the geographic distance between colonies might play a role, their impact/incidence on gene flow may vary between species and colonies.

Highlights

Oceanic fronts divide the Southern Ocean into water masses with different physical characteristics, in terms of temperature and salinity[1] which have given rise to different biogeographical provinces; the physical variables are associated with changes in species composition[2,3]
The speciation and diversification of southern (E. chrysocome) and eastern (E. filholi) from northern (E. moseleyi) rockhopper penguins might be explained by the presence of the Subtropical Front (STF) as a biogeographical barrier coupled with a historical shift in their geographical distribution, may have resulted in the isolation of common ancestral populations[14,35]
Northern rockhopper (E. moseleyi) penguins exhibited the lowest haplotype and nucleotide diversity for cytochrome oxidase subunit for penguins (COI), AK, ODC, and very low for HVRI for both locations compared with all other species; southern rockhoppers (E. chrysocome) showed the highest genetic diversity

Summary

Introduction

Oceanic fronts divide the Southern Ocean into water masses with different physical characteristics, in terms of temperature and salinity[1] which have given rise to different biogeographical provinces; the physical variables are associated with changes in species composition[2,3]. Four are endemic to New Zealand, subantarctic New Zealand islands and Macquarie Island (Fiordland E. pachyrhynchus, Snares E. robustus; royal E. schlegeli and erect-crested E. sclateri); in contrast, species of rockhopper (northern E. moseleyi, southern E. chrysocome, and eastern E. filholi) and macaroni penguins (E. chrysolophus) exhibit a broader distribution in the Southern Ocean[14,15,16,17]. The speciation and diversification of southern (E. chrysocome) and eastern (E. filholi) from northern (E. moseleyi) rockhopper penguins might be explained by the presence of the STF as a biogeographical barrier coupled with a historical shift in their geographical distribution, may have resulted in the isolation of common ancestral populations[14,35]. White-faced penguins recently reported at Marion Island[15] were compared with macaroni and royal penguins to help clarify their taxonomic origin

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Results

Conclusion