Ocypodidae Rafinesque, 1815: 96 [as Ocypodia, corrected to Ocypodidae by MacLeay, 1838: 63. Name No. 375 on Official List of Family-group Names in Zoology, see International Commission on Zoological Nomenclature (ICZN, 1964: Opinion 712]. Type genus: Ocypode Weber, 1795.

Ucainae Dana, 1851: 289. Type genus: Uca Leach, 1814.

Gelasimiden Nauck, 1880: 8, 17, 23, 64, 66 [not Latinised, invalid for nomenclatural purposes].

Gelasimidae Miers, 1886: viii. Type genus: Gelasimus Latreille, 1817.

Diagnosis. Carapace deep, subquadrilateral to subovate; dorsal regions indistinct to prominently demarcated; anterolateral margins straight, slightly arched or strongly convex; fronto-orbital distance more than half maximum carapace width; front broad to relatively narrow, deflexed, usually forming lobe between eyestalks; antennules folding obliquely or almost vertically; antennular flagellum small or rudimentary; proepistome broad; third maxillipeds completely or almost completely closing buccal cavern; exopod visible in part or completely, with or without flagellum; chelipeds unequal in adult males, sometimes remarkably so; most species with brush of long setae lining pouch leading into branchial cavity between bases of second and third ambulatory legs; thoracic sternum broad posteriorly; male thoracic sternum narrowed posteriorly, only small part of sternite 8 visible when pleon closed; male gonopore sternal, adjacent to suture between sternites 7 and 8; adult male pleon relatively wide, subrectangular, long, telson reaching or near buccal cavity; somites 4–6 or 5 and 6 partly or completely fused; pleonal locking mechanism usually absent; G1 stout, strongly chitinised, with short pectinate tip fringed with stiff setae which obscuring surface.