Systematics of the family Ocypodidae Rafinesque, 1815 (Crustacea: Brachyura), based on phylogenetic relationships, with a reorganization of subfamily rankings and a review of the taxonomic status of Uca Leach, 1814, sensu lato and its subgenera.

The family Ocypodidae is a group of intertidal brachyuran crabs found in tropical to temperate seas worldwide. While the family has historically included many subfamilies, most of these have now been given separate family status within the superfamily Ocypodoidea. The most recent classification recognises only two subfamilies, the ghost crabs: Ocypodinae Rafinesque, 1815; and the fiddler crabs: Ucinae Dana, 1851. The ghost crabs comprise 21 species in two genera, Ocypode Weber, 1795, and Hoplocypode Sakai & Türkay, 2013. The fiddler crabs are the most species-rich group of this family with 104 species, all belonging to the single genus Uca Leach, 1814, with 12 recognised subgenera. The present study supports 13 groups (= genera) belonging to three revised subfamilies. This result is based on molecular evidence from the nuclear 28S rDNA, and the mitochondrial 16S rDNA and cytochrome oxidase subunit I (COI). The family now also includes the monogeneric Ucididae Števčić, 2005, recently recognised as a separate family for Ucides Rathbun, 1897, herein relegated to a subfamily of the Ocypodidae. Uca (and thus Ucinae) is shown to be paraphyletic, belonging to two widely divergent clades. Uca (Uca) s. str. from the Americas and Afruca Crane, 1975, from the East Atlantic cluster with Ocypode and Hoplocypode, and thus constitute a revised Ocypodinae. The American broad-fronted group with the Indo-West Pacific subgenera, forming a distinct clade, for which the subfamily name Gelasiminae Miers, 1886, is available. Australuca Crane, 1975, and Hoplocypode Sakai & Türkay, 2013, are not supported, and are treated as synonyms of Tubuca Bott, 1973, and Ocypode, respectively. All other subgenera of Uca are here recognised as full genera. The three constituent subfamilies of the Ocypodidae are thus as follow: Ocypodinae (Afruca; Ocypode; Uca s. str.); Gelasiminae (Austruca Bott, 1973; Cranuca Beinlich & von Hagen, 2006; Gelasimus Latreille, 1817; Leptuca Bott, 1973; Minuca Bott, 1954; Paraleptuca Bott, 1973; Petruca Shih, Ng & Christy, 2015; Tubuca; Xeruca Shih, 2015); and Ucidinae Števčić, 2005 (Ucides)