Fragile seashores were 'cradle of evolution' for early fish

Sacabambaspis, a 460 million year old jawless relative of modern jawed fishes, swims in the shallow coastal waters of modern day Bolivia. Credit: Nobumichi Tamura

Evolution of the major groups of fish that we recognise today took place in shallow waters, close to the seashore, according to new research at the University of Birmingham. 

The findings, published in Science suggest that, while coral reefs may be vital for diversification at the present day, fragile near shore environments were crucial for evolution some 480-360 million years ago.

Researchers in the School of Geography, Earth and Environmental Sciences, working with colleagues at the Universities of Pennsylvania, Michigan and Manchester, surveyed fossil records of primitive fish across the globe.

“Most of today’s major groups of fishes, from jawless hagfish and lampreys through to sharks and the bony fish we are familiar with make their first appearance during the Ordovician, around 480 million years ago, or shortly thereafter” says Dr Ivan Sansom, senior lecturer in palaeobiology at the University of Birmingham and co-lead author of the study. “The big surprise for us was that all of these seem to have started their evolutionary journey in these very shallow waters close to the shoreline.”

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