Data from: Thorson’s rule, life history evolution and diversification of benthic octopuses (Cephalopoda: Octopodoidea)

Here we evaluate the so-called Thorson’s rule, which posits that
direct-development and larger eggs are favored towards 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.