Open Access

Rowland M. Shelley

• Past concepts and synonymies of Anadenobolus monilicornis (Porat, 1876) (Spirobolida: Rhinocricidae), including the implied synonymy of Rhinocricus ectus Chamberlin, 1920, are consolidated into a formal account with the fi rst illustrations of the holotype. Prior to 1492, A. monilicornis was probably indigenous to an unknown number of southern Antillean islands, but through modern commerce, man has introduced it to Florida, Bermuda, Barbados, the Cayman Islands, and Jamaica, and probably repeatedly (re)introduced conspecifi c material to all the Lesser Antilles, resulting in subcontinuous gene pool mixing and reticulate evolution. A broad species concept is necessary to encompass the multitudinous variants, some of which have been recognized as species; only one true Caribbean species of Anadenobolus Silvestri, 1897, may exist, for which arboreus (Saussure, 1859) is the oldest name. The distribution of A. monilicornis presently extends from Bermuda and southern coastal Florida through the Greater and Lesser Antilles (excepting Cuba) to eastern coastal Venezuela and central Suriname, with outlier populations in Jamaica, the Cayman Islands, and Tampa Bay and the eastern Floridian panhandle; excepting Barbados, the indigenous range may have extended from Hispaniola through the same area. Introductions into Manitoba, Canada, and North Carolina, USA, have not yielded viable populations. Localities are newly recorded from St. Thomas, US Virgin Islands.