Darby (2015b) revised the generic description, discussed the relationships with other closely related genera, and described Nossidium katyae from Bolivia, the only known representative of the genus in S. America. The only mention of the genus in Central America is by Dybas (1976) who recorded seeing a species possibly related to Nossidium collected at 7,600 feet on the Volcan Chiriqui in Panama on the Costa Rica border. Three species have been described from North America, N. americanum and N. amoenum by Motschulsky 1868 (as Anisarthria) and N. posthumum by Matthews 1874. Examples of these species in BMNH have been examined to confirm possible synonymy with the new Costa Rican species but have proved to be quite different particularly in their more parallel, less rounded form, which is similar to that of N. pilosellum, the type species of the genus.