The Plectoceratidae is a family of tarphycerids in the suborder Barrandeocerina established as a place for the genus Plectoceras; defined (Sweet 1964) simply as coiled, costate barrandeocerids with subcentral adult siphuncle. According to Sweet, in the original Treatise Part K,the Plectoceratidae included only Plectoceras. Flower, 1984, however added six other genera, two new and four removed from both the Barrandeoceratidae and Apsidoceratidae. Genera according to Flower, 1984 are: