A team of researchers from the University of Southampton have described a new species of Yeti Crab – discovered living in the hydrothermal vent systems of the East Scotia Ridge in the Southern Ocean, Antarctica.
Yeti crabs belong to a group of squat lobsters, known as Kiwaidae (named after Kiwa the Polynesian goddess of shellfish), that thrive in the hot waters surrounding the geothermally heated hydrothermal vents. It is the dominant species at these sites occurring at extremely high densities, exceeding 700 specimens per square metre.
The newly described species Kiwa tyleri is named after world-renowned British deep-sea and polar biologist Professor Paul Tyler from the University of Southampton. This species is morphologically similar to other members of the Kiwaidae family, with the majority of it’s body covered in dense bristles – known as setae. This gives the crab a furry appearance much like the legendary Yeti or Abominable Snowman, hence the group’s common name.
This hairlike setae that covers much of the yeti crabs body, specifically its chelipeds, walking legs and the ventral surface of its cephalothorax, have been shown to host clusters of filamentous chemosynthetic bacteria including epsilon-Proteobacteria, gamma-Proteobacteria and Bacteroidetes 1. These bacteria are thought to be a nutritional source for the yeti crab. The newfound species is apparently better built for climbing than its kin—since it has shorter and more robust front limbs. K. tyleri is also more stout and compact than its other members of the yeti crab family. This physique likely allows the crustacean to jockey for position on vents’ vertical surfaces.
Dr Sven Thatje from the University of Southampton and lead author on the paper, says:
“The Antarctic Yeti Crab is trapped in its warm-water hydrothermal vent site by the cold polar waters of the surrounding deep-sea. The species has adapted to this very limited sized habitat — of a few cubique metres in volume — by living in highly-packed densities and by relying on bacteria they grow on their fur-like setae for nutrition.”
See below for a video of yeti crabs surrounding a thermal vent and the highly packed conditions in which they live.
Sven Thatje , Leigh Marsh, Christopher Nicolai Roterman, Mark N. Mavrogordato, Katrin Linse. Adaptations to Hydrothermal Vent Life in Kiwa tyleri, a New Species of Yeti Crab from the East Scotia Ridge, Antarctica. PLoS One, 2015 DOI: 10.1371/journal.pone.0127621