Thorson's rule, life-history evolution, and diversification of benthic octopuses (Cephalopoda: Octopodoidea)

Christian M. Ibáñez, Enrico L. Rezende, Roger D. Sepúlveda, Jorge Avaria-Llautureo, Cristián E. Hernández, Javier Sellanes, Elie Poulin, M. Cecilia Pardo-Gandarillas

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Here, we evaluate the so-called Thorson's rule, which posits that direct-development and larger eggs are favored toward the poles in marine organisms and whose validity been the subject of considerable debate in the literature, combining an expanded phenotypic dataset encompassing 60 species of benthic octopuses with a new molecular phylogeny. Phylogenetic reconstruction shows two clades: clade 1 including species of the families Eledonidae, Megaleledonidae, Bathypolypodidae, and Enteroctopodidae, and clade 2 including species of Octopodidae. Egg size, development mode, and all environmental variables exhibited phylogenetic signal, partly due to differences between the two clades: whereas most species in clade 1 inhabit cold and deep waters, exhibit large eggs and hatchling with holobenthic development, species from clade 2 inhabit tropical-temperate and shallow waters, evolved small eggs, and generally exhibit merobenthic development. Phylogenetic regressions show that egg size exhibits a conspicuous latitudinal cline, and that both egg size and development mode vary with water temperature. Additionally, analyses suggest that egg size is constrained by body size in lineages with holobenthic development. Taken together, results suggest that the variation in egg size and development mode across benthic octopuses is adaptive and associated with water temperature, supporting Thorson's rule in these organisms.

Original languageEnglish
Pages (from-to)1829-1839
Number of pages11
JournalEvolution
Volume72
Issue number9
DOIs
Publication statusPublished - 1 Sep 2018

Keywords

  • Egg size
  • holobenthic
  • life histories
  • macroevolution
  • merobenthic
  • phylogeny

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Agricultural and Biological Sciences(all)

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  • Cite this

    Ibáñez, C. M., Rezende, E. L., Sepúlveda, R. D., Avaria-Llautureo, J., Hernández, C. E., Sellanes, J., Poulin, E., & Pardo-Gandarillas, M. C. (2018). Thorson's rule, life-history evolution, and diversification of benthic octopuses (Cephalopoda: Octopodoidea). Evolution, 72(9), 1829-1839. https://doi.org/10.1111/evo.13559