Friday, June 21, 2013

Evolution added a photo from June 21, 2013 to their timeline.
New research reveals the origin of The Hoff - the Hoff yeti crab, that is.

When these crabs were found in 2011, their hairy chests reminded researchers of David Hasselhoff. These hairs trap bacteria where it can be "farmed" until the crab scrapes it off with its comb-like mouthparts and eats it. The crabs live in the deep sea, more than 2000m down, and live around hydrothermal vents where they can feed their bacteria in the mineral-rich vent water. It's a fine line between being close enough to reach minerals and getting boiled alive in the 380°C (716 Fahrenheit) water.

It was previously thought that yeti crabs were "living fossils", but new research shows all four yeti crab species have a common ancestor around 35-40 million years ago. DNA analysis suggests the crabs originated around vents in the eastern Pacific Ocean and migrated west, with larvae hitching rides in fast-moving ocean currents.

Current vent species can be traced back around 55 million years to a period of global warming, when the atmosphere warmed and deep sea oxygen levels dropped. This could have killed off the vent species of the time and cleared the way for yeti crabs to move in.

"Yeti crabs and other such creatures may in fact be especially prone to extinction when there is less oxygen available in the deep ocean,’ says Dr Nicolai Roterman (of Oxford University, UK). "This is because if deep-sea ocean oxygen levels fall, the amount of oxygen available to these animals - which already live in an oxygen-poor environment at the limits of their physiological tolerance - may drop below the minimum level at which they can survive. They would face the stark choice of "suffocate or starve"."

To read the paper: http://bit.ly/14mtvwq

Photo: Close-up of "The Hoff" Yeti crab (credit to David Shale). Colonies of crabs around heat vents on the East Scotia Ridge in the Southern Ocean (CHESSO Consortium).

http://www.ox.ac.uk/media/news_stories/2013/130619.html

http://www.livescience.com/37532-yeti-crab-evolution.html

http://www.bbc.co.uk/news/science-environment-22952728

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