10.5061/DRYAD.547D7WM7D
Axelrod, Caleb
0000-0002-6130-0168
University of Guelph
Laberge, Frederic
0000-0002-2469-9720
University of Guelph
Robinson, Beren
0000-0003-2868-5411
University of Guelph
Interspecific and intraspecific comparisons reveal the importance of
evolutionary context in sunfish brain form divergence
Dryad
dataset
2021
2021-01-21T00:00:00Z
2021-01-21T00:00:00Z
en
32894 bytes
3
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Habitats can select for specialized phenotypic characteristics in animals.
However, the consistency of evolutionary responses to particular
environmental conditions remains difficult to predict. One trait of great
ecological importance is brain form, which is expected to vary between
habitats that differ in their cognitive requirements. Here we compared
divergence in brain form and oral jaw size across a common
littoral-pelagic ecological axis in two sunfishes at both the
intraspecific and interspecific levels. Brain form differed between
habitats at every level of comparison, however divergence was
inconsistent, despite consistent differences in oral jaw size. Pumpkinseed
and bluegill species differed in cerebellum, optic tectum, and olfactory
bulb size. These differences are consistent with a historical ecological
divergence because they did not manifest between littoral and pelagic
ecotypes within either species, suggesting constraints on changes to these
regions over short evolutionary time scales. There were also differences
in brain form between conspecific ecotypes, but they were inconsistent
between species. Littoral pumpkinseed had larger brains than their pelagic
counterpart, and littoral bluegill had smaller telencephalons than their
pelagic counterpart. Inconsistent brain form divergence between
conspecific ecotypes of pumpkinseed and bluegill sharing a common
littoral-pelagic habitat axis suggests that contemporary ecological
conditions and historic evolutionary context interact to influence
evolutionary changes in brain form in fishes.