Evolutionary diversification in the marine realm: A global case study with marine mammals

Ben G. Holt*, Felix G. Marx, Susanne A. Fritz, Jean Philippe Lessard, Carsten Rahbek

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

12 Citations (Scopus)
93 Downloads (Pure)

Abstract

Speciation is thought to be predominantly driven by the geographical separation of populations of the ancestral species. Yet, in the marine realm, there is substantial biological diversity despite a lack of pronounced geographical barriers. Here, we investigate this paradox by considering the biogeography of marine mammals: cetaceans (whales and dolphins) and pinnipeds (seals and sea lions). We test for associations between past evolutionary diversification and current geographical distributions, after accounting for the potential effects of current environmental conditions. In general, cetacean lineages are widely dispersed and show few signs of geographically driven speciation, albeit with some notable exceptions. Pinnipeds, by contrast, show a more mixed pattern, with true seals (phocids) tending to be dispersed, whereas eared seals (otariids) are more geographically clustered. Both cetaceans and pinnipeds show strong evidence for environmental clustering of their phylogenetic lineages in relation to factors such as sea temperature, the extent of sea ice, and nitrate concentrations. Overall, current marine mammal biogeography is not indicative of geographical speciation mechanisms, with environmental factors being more important determinants of current taxonomic distributions. However, geographical isolation appears to have played a role in some important taxa, with evidence from the fossil record showing good support for these cases.

Original languageEnglish
JournalFrontiers of Biogeography
Volume12
Issue number3
Pages (from-to)1-14
Number of pages14
ISSN1948-6596
DOIs
Publication statusPublished - 2020

Bibliographical note

Publisher Copyright:
© the authors.

Keywords

  • Barriers
  • Biogeography
  • Dispersal
  • Ecology
  • Evolution
  • Oceanic
  • Phylo-betadiversity
  • Phylogenetic diversity

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