A new species and genus of a new monokonophoran family (Crustacea: Tanaidacea), from southeastern Florida

The monotypic family Cirratodactylidae fam. nov., based on Cirratodactylus floridensis gen. et sp. n., differs fundamentally from the other families in the tanaidacean suborder Mono‐konophora in the following combination of characters: a mandibular palp composed of a single article, the absence of a palp on the first maxilla (=maxillule), and the presence of numerous slender, recurved curls distally on the dactyli of pereopods II‐VIII. The chelipeds of Cirratodactylus floridensis bear rudimentary oostegites at both the preparatory and copulatory female stages. In the latter instar the single marsupium is formed by the fused oostegites of pereopods II‐V only, and those of the chelipeds, although present, regress and fail to participate in the marsupium. Although the literature commenting on the presence and function of tanaidacean oostegites is scanty and contradictory, this study establishes that certain other monokonophoran taxa agree in the distribution of oostegites with Cirratodactylus , whereas yet others have only four pairs of oostegal plates, borne on pereopods II‐V.