Evolution: Crabs go deep to avoid...(tatives of this family are trapped in th...)

In order to leave this geographic bottleneck and spread around the world, the shallow water ancestors of current deep-sea groups had to go deep and adapt to the challenges of life in the deep sea. The process of adaptation to constant low temperatures (1-4C) prevailing in the deep sea seems to have narrowed the temperature tolerance range of the crabs where they have emerged to the surface waters in the Southern Hemisphere. With differences of only a couple of degrees in temperature affecting the distribution of the king crab, it is difficult to predict the consequences of range expansion in the warming waters around the Antarctic Peninsular region.

King crabs are of great commercial value, and fisheries are established in high latitude regions of both hemispheres. "Understanding their evolutionary history and ecology is key to supporting sustainable fisheries of these creatures," said research student Sally Hall: "Recent range extensions of king crabs into Antarctica, as well as that of the red king crab Paralithodes camtchaticus in the Barents Sea and along the coast off Norway emphasise the responsiveness of this group to rapid climate change."

This study elucidates temperature as a driving force behind the speciation and radiation of a major seafloor predator globally and over tens of millions of years of Earth's history.

The study has been supported by the National Environment Research Council (UK) through a PhD studentship to Sally Hall, and a Research Grant from the Royal Society awarded to Sven Thatje.

'/>"/>