Hoff crab | |
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Dorsal view of carapace showing distinctive markings | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Crustacea |
Class: | Malacostraca |
Order: | Decapoda |
Family: | Kiwaidae |
Genus: | Kiwa |
Species: | K. tyleri |
Binomial name | |
Kiwa tyleri Thatje S, Marsh L, Roterman CN, Mavrogordato MN, Linse K, 2015 |
The "Hoff crab" is a species of deep-sea squat lobster in the family Kiwaidae, which lives on hydrothermal vents near Antarctica. The crustacean was given its nickname in 2010 by UK deep-sea scientists aboard the RRS James Cook, owing to resemblance between its dense covering of setae on the ventral surface of the exoskeleton and the hairy chest of the actor David Hasselhoff. The 2010 expedition to explore hydrothermal vents on the East Scotia Ridge was the second of three expeditions to the Southern Ocean by the UK led research consortium, ChEsSo (Chemosynthetic Ecosystems of the Southern Ocean).
This species – the only member of its genus found outside the Pacific Ocean, is known from two sites adjacent to and on the chimney sides of hydrothermal vents in the East Scotia Ridge of the south Atlantic Ocean: from around 2,394 metres (7,854 ft) depth at the E9 vent site and from around 2,608 m (8,556 ft) depth at the E2 site.
Phylogenetic analysis of the mitochondrial 16S ribosomal RNA gene and a range of other anomuran crustaceans, using Bayesian inference, places this species from the East Scotia Ridge as a sister taxon to Kiwa hirsuta, with a sequence divergence from this species of 6.45%, which is consistent for within-genus divergence in squat lobsters.
Unlike the two currently described species of the genus, Kiwa hirsuta and Kiwa puravida, which are notable for having a dense covering of setae on their elongated chelae, this species has shorter chelae, with most of the setae concentrated instead on the ventral surface of the crab.
Filamentous bacteria were found on the setae and similar-looking sulfur-oxidising bacteria have been found amongst the setae of Kiwa hirsuta and Kiwa puravida. It has been hypothesised that these sulfur-oxidising bacteria, which fix carbon from the water by oxidising sulfides in the hydrothermal fluid, are a significant source of nutrition to the crabs.