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The asterinid sea star family provides a powerful taxon with which to examine developmental processes in evolution because it includes genera (eg. Patiriella, Cryptasterina, Parvulastra) that contain species with indirect (planktotrophic) development through typical feeding larvae and several modes of direct (lecithotrophic) development through non-feeding larvae. A dispersive feeding larva is considered ancestral for the Echinodermata.
We have constructed a robust phylogeny for these genera with calibrated divergence times to map polarity and timing of life history change on an evolutionary time scale. Comparative embryology shows that evolutionary modification of development involved a range of mechanisms including deletion, heterochrony and hypertrophy. Some of the changes were surprisingly fast (< 0.5 Mya). Our results challenge the paradigm that early embryogenesis is constrained against change. The research is determining what features are conserved and what features are labile to change and the mechanisms involved. |
Evo-Devo and Echinoderm Development |
- Evo-Devo and the Asterinidae |
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Integrative Biology and Evolution of Marine and Freshwater Invertebrates |
