title: The biogeography of the yeti crabs (Kiwaidae) with notes on the phylogeny of the Chirostyloidea (Decapoda: Anomura).
abstract: The phylogeny of the superfamily Chirostyloidea (Decapoda: Anomura) has been poorly understood owing to limited taxon sampling and discordance between different genes. We present a nine-gene dataset across 15 chirostyloids, including all known yeti crabs (Kiwaidae), to improve the resolution of phylogenetic affinities within and between the different families, and to date key divergences using fossil calibrations. This study supports the monophyly of Chirostyloidea and, within this, a basal split between Eumunididae and a Kiwaidae-Chirostylidae clade. All three families originated in the Mid-Cretaceous, but extant kiwaids and most chirostylids radiated from the Eocene onwards. Within Kiwaidae, the basal split between the seep-endemic Kiwa puravida and a vent clade comprising Kiwa hirsuta and Kiwa spp. found on the East Scotia and Southwest Indian ridges is compatible with a hypothesized seep-to-vent evolutionary trajectory. A divergence date estimate of 13.4-25.9 Ma between the Pacific and non-Pacific lineages is consistent with Kiwaidae spreading into the Atlantic sector of the Southern Ocean via the newly opened Drake Passage. The recent radiation of Kiwaidae adds to the list of chemosynthetic fauna that appear to have diversified after the Palaeocene/Eocene Thermal Maximum, a period of possibly widespread anoxia/dysoxia in deep-sea basins.
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK. christopher.roterman@zoo.ox.ac.uk
authors.forename: C N
authors.initials: CN
authors.lastname: Roterman
authors.forename: J T
authors.initials: JT
authors.lastname: Copley
authors.forename: K T
authors.initials: KT
authors.lastname: Linse
authors.forename: P A
authors.initials: PA
authors.lastname: Tyler
authors.forename: A D
authors.initials: AD
authors.lastname: Rogers
mesh_terms: D000818:Animals; D033381:Anomura / Q000235:genetics; D005075:Biological Evolution; D033364:Decapoda / Q000235:genetics*; D005580:Fossils; D010802:Phylogeny; D058974:Phylogeography; D011506:Proteins / Q000235:genetics; D012336:RNA, Ribosomal, 16S; D012339:RNA, Ribosomal, 28S; D013997:Time Factors
chemical_list: D011506:Proteins; D012336:RNA, Ribosomal, 16S; D012339:RNA, Ribosomal, 28S
keywords: Chirostyloidea; Kiwaidae; biogeography; hydrothermal vents; phylogenetics; yeti crab