First species of yeti crab from hydrothermal vent systems near Antarctica described

Date:June 24, 2015

Source:University of Southampton

Summary:The first species of yeti crab from hydrothermal vent systems of the East Scotia Ridge in the Southern Ocean, Antarctica, has been described. This Yeti Crab is famous for its body, which is densely covered by bristles -- known as setae -- and bacteria, giving it a fur-like appearance.

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How the Hairy-Chested 'Hoff' Crab Evolved

Yeti crabs don't comb their hair to look good — they do it because they're hungry.

These bizarre deep-sea animals grow their food in their own hair, trapping bacteria and letting it flourish there before "combing" it out and slurping it up. The crabs are found near cold seeps and hydrothermal vents, places where mineral-rich water spews out of the seafloor.

Like many animals that live in these extreme environments, yeti crabs have been thought of as "living fossils," largely isolated from the rest of world and, therefore, unchanged for eons. But new research shows these animals actually evolved relatively recently, suggesting the deep-sea environments the crabs call home may be more changeable than previously thought and more vulnerable to shifts in the atmosphere and climate, said Oxford University researcher Nicolai Roterman. 

A study by Roterman and his colleagues detailing the evolutionary history of these bizarre creatures was published today (June 18) in the journal Proceedings of the Royal Society B, and their research turned up a few surprises.

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5tDancing for Food in the Deep Sea: Bacterial Farming by a New Species of Yeti Crab (via Chad Arment)

Vent and seep animals harness chemosynthetic energy to thrive far from the sun's energy. While symbiont-derived energy fuels many taxa, vent crustaceans have remained an enigma; these shrimps, crabs, and barnacles possess a phylogenetically distinct group of chemosynthetic bacterial epibionts, yet the role of these bacteria has remained unclear. We test whether a new species of Yeti crab, which we describe as Kiwa puravida n. sp, farms the epibiotic bacteria that it grows on its chelipeds (claws), chelipeds that the crab waves in fluid escaping from a deep-sea methane seep. Lipid and isotope analyses provide evidence that epibiotic bacteria are the crab's main food source and K. puravida n. sp. has highly-modified setae (hairs) on its 3rd maxilliped (a mouth appendage) which it uses to harvest these bacteria. The ε- and γ- proteobacteria that this methane-seep species farms are closely related to hydrothermal-vent decapod epibionts. We hypothesize that this species waves its arm in reducing fluid to increase the productivity of its epibionts by removing boundary layers which may otherwise limit carbon fixation. The discovery of this new species, only the second within a family described in 2005, stresses how much remains undiscovered on our continental margins.


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