Family Anarthruridae Lang, 1971

Diagnosis (after Bird 2004). Female cephalothorax shorter than pereonites 1 and 2 together. Pereonite 6, pleonites and pleotelson sometimes fused or partly fused. Antennule with four articles, with or without minute terminal caplike article. Antenna with six articles, article 2 with dorsal seta. Mandibles reduced or even absent. Maxillule endite with seven to ten terminal spiniform setae. Maxilliped bases and endites together oval or heart-shaped. Epignath without terminal spiniform seta. Cheliped attached via prominent pseudocoxa. Pleopods present or absent. Uropod basal article fused with exopod.

Male. Generally as the female but pleon fusion is either incomplete or absent. Mouthparts functional. Pleopods always present.