Taxonomic and ecological interest in squat lobsters has grown considerably over the last two decades. A checklist of the 870 current valid species of squat lobsters of the world (families Chirostylidae, Galatheidae and Kiwaidae) is presented. The compilation includes the complete taxonomic synonymy and geographical distribution of each species plus type information (type locality, repository and registration number). The numbers of described species in the world’s major ocean basins are summarised.

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 3^rd 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.

The high level classification of the Chirostyloidea Ortmann, 1892, is reviewed. Eumunididae Milne-Edwards & Bouvier, 1900, is resurrected for two genera formerly placed in the Chirostylidae Ortmann, 1892, Eumunida Smith, 1883, and Pseudomunida Haig, 1979, based on shared characteristics such as the dorsal carapace striation, presence of supraocular spines of the rostrum, dentition of the mandible, presence of an epipod and an annulated exopod flagellum of maxilliped 1. Three families are now included in the Chirostyloidea: Chirostylidae, Eumunididae and Kiwaidae. Diagnoses are provided for each family as well as a key to the families. The fossil record of the Chirostyloidea is discussed, with putative records of Eumunida in the fossil record referred to the galatheid genus Sadayoshia Baba, 1969.