All genera previously referred to the Carcineretidae are herein evaluated, and the family is restricted to three genera, Carcineretes, Cancrixantho, and Mascaranada, for which diagnoses are provided. Ophthalmoplax and Longusorbis are herein removed to the Portunidae, and Longusorbis eutychius new species is described from the Eocene Tepetate Formation of Baja California Sur, Mexico, extending t...