The unusual, hairy "yeti crab" represents not only a new species, but also a new family of crustaceans

During a series of submersible dives on the Easter Island Microplate, Michel Segonzac, a Census of Marine Life scientist participating in the March-April 2005 PAR 5 Research Expedition, encountered a unique "hairy" crustacean on a hydrothermal site. Dubbed the "Yeti Crab", the crustacean so interested the scientists that they collected a specimen for examination.

This "Yeti Crab" has not been previously encountered in 30 + years of hydrothermal vent exploration. It has proved to be new to science and has been classified as belonging to a new family of crustaceans. Being described as a decapod crustacean, the Yeti Crab would be related to crabs, lobster, and shrimp. However, close examination has revealed that the unique morphology, including a lack of eyes and a profusion of hairlike setae , as well as the genetic code of this organism (tentatively named Kiwa hirsuta) does not fall within the boundaries of previously described taxonomic groups. This has led to the description and proposal of the new family Kiwaidae, named after Kiwa the Polynesian goddess of shellfish. Further study has led scientists to propose that this family may constitute what is known in taxonomy as a basal lineage. While similar to other species and families of the superfamily Galatheoidea, the Kiwaidae family could prove to be the potential origin for the other three known Galatheoidea families.

Observed and collected from depths of more than 2000 m, Kiwa hirsuta appears common on and around hydrothermal vents on pillow basalt substrates and has been observed feeding on the tissue of mussels (although it is assumed to be omnivorous as most decapods are). Additionally, the hairlike setae that cover much of its body host mats of chemosynthetic bacteria that may also provide a nutritional source for the yeti crab.

The abundance of the yeti crab in the area where the first individual was collected, as well as the lack of previous encounters with them, has prompted researchers to surmise that these creatures have a limited geographic range. As the majority of explored hydrothermal vent sites have been located in the middle latitudes, CheSS scientists have proposed a northern limit for this species at around 38°S and believe that geographical boundaries such as the Juan Fernandez Microplate may also play a part in its isolation.

A formal description and additional information on this new species/family can be found in the following article: A new Squat Lobster family of Galatheoidea (Crustacea, Decapoda, Anomura) from the hydrothermal vents of the Pacific-Antarctic Ridge. Zoosystema 27(4): 709-723.

Cruise Location: the spreading ridges along the East Pacific Rise and Pacific-Antarctic Ridge (left), near tiny Easter Island, which is not even visible in this view of the Earth, and only barely visible in the figure below.

• What: Discovery of a new species of crustacean from the new family Kiwaidae on a hydrothermal site.
• Who: ChESS Scientists --> E. MacPherson, W. Jones, M. Segozac
• When: March-April 2005 (PAR 5 Cruise --> MBARI)
• Where: Pacific-Antarctic Ridge in the South Pacific Ocean (37°46.50'S, 110°54.70'W)
• How: Collected by slurp gun from the Alvin submersible at 2228 M water depth
• Reference: Macpherson E., Jones J. & M. Segonzac, 2005. A new Squat lobster family of Galatheoidea (Crustacea, Decapoda, Anomura) from the hydrothermal vents of the Pacific-Antarctic Ridge. Zoosystema 27(4): 709-723.