Limpets provide new insight into ocean biodiversity

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A unique partnership of scientists, traditional practitioners, volunteers and resource managers have found that marine speciation may hold secrets for biodiversity and evolution as a whole.

Scientists have long wondered why there are so many species in the sea and how these species form and Hawaii has always been a prime example of this with over 30% of the marine species being endemic (unique) to Hawaii.

With one of the highest rates of endemism in the world Dr Chris Bird and colleagues from the Hawai'i Institute of Marine Biology (HIMB) set about examining the evolution of three species of limpets.

While examples of adaptive radiations can be seen in species such as the Hawaiian honeycreepers and even fruit flies, the team were intrigued as to why it appeared that marine species colonised Hawaii and then diverged to an isolated native species with no further speciation or specialisation.

They found that where previously it was thought that the three species of limpet - locally known as 'opine' - had colonised Hawaii independently on three separate occasions, in fact using DNA, fossil and geology they discovered that the Japanese limpet had colonised Hawaii only once five million years ago. The 'opine' then speciated Hawaii according to the ecology of the habitat to form three species: (in order from shallow to deep) 'opihi makai'auli, 'opihi 'alinalina, 'opihi ko'ele. Each species having different tolerances for particular shore levels and with different timings for the production of sperm and eggs.

Bird states: "The research on 'opihi give us better insight to the processes that produce biodiversity, especially in the ocean where the speciation process is not well understood. These studies reset the bar for what is considered possible in marine speciation."

By working together with various organisations, the community and volunteers, the scientists hope to incorporate crucial information passed down through generations of Native Hawaiians.

For more information see: Christopher E. Bird, Brenden S. Holland, Brian W. Bowen, Robert J. Toonen. Diversification of sympatric broadcast-spawning limpets (Cellana spp.) within the Hawaiian archipelago. Molecular Ecology, 2011; 20 (10): 2128 DOI: 10.1111/j.1365-294X.2011.05081.x

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