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Updated: May 20, 2026
08:02
Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
Published on: May 7, 2016
Developmental dissociation in morphological evolution of the stickleback opercle.
Charles B Kimmel1, Paul A Hohenlohe, Bonnie Ullmann
1Institute of Neuroscience, University of Oregon, Eugene, 97403, USA. kimmel@uoneuro.uoregon.edu
Evolution & Development
|July 7, 2012
Summary
Oceanic threespine sticklebacks invading freshwater evolve opercle bone shape by truncating development. This developmental shift allows freshwater sticklebacks to achieve a new adult morphology resembling juvenile oceanic forms.
Area of Science:
- Evolutionary biology
- Developmental biology
- Comparative morphology
Background:
- Oceanic threespine sticklebacks exhibit repeated, independent evolution of new freshwater morphologies.
- A consistent change in opercle bone shape is a key derived feature in freshwater populations.
Purpose of the Study:
- To investigate the developmental basis of opercle shape evolution in threespine sticklebacks transitioning from oceanic to freshwater environments.
- To determine if opercle shape evolution in freshwater sticklebacks involves changes in developmental timing or dissociation.
Main Methods:
- Multivariate morphometric analysis of opercle shape development from larval to adult stages in oceanic and freshwater threespine sticklebacks.
- Comparison of developmental trajectories and adult phenotypes between oceanic and freshwater populations.
Main Results:
- The primary axis of opercle shape development in oceanic sticklebacks mirrors the axis of evolutionary change seen in freshwater populations.
- Freshwater adult opercle shape closely resembles the juvenile shape of oceanic sticklebacks, indicating developmental truncation.
- Derived freshwater phenotypes exhibit dissociated ontogenetic changes, suggesting modular development.
Conclusions:
- Evolution of freshwater threespine stickleback morphology is largely driven by truncation of developmental processes.
- Dissociated ontogenetic changes in the opercle may reflect underlying developmental modularity, facilitating evolutionary flexibility.
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