Orthalicus Reses - Distribution

Distribution

Henry Augustus Pilsbry suggested, in 1946, that Orthalicus reses reses arrived in Florida from Central America and the Caribbean shortly after the emergence of the Florida peninsula in the late Pleistocene. Snails that were sealed in place on floating tropical trees may have been cast ashore on the Florida peninsula by high winds and hurricanes. This form of dispersal has been suggested for both Orthalicus and Liguus, but the exact origin of these species is still in question. In 1972, Craig suggested that populations of Orthalicus arrived directly across the Gulf of Mexico from Central America, but the mode of transportation and whether dispersal occurred as a single event or multiple events was not known. No one knows when Orthalicus reses reses arrived in the Lower Keys.

Historically, the Stock Island tree snail was believed to have a very limited distribution, being found only in tropical hardwood hammocks on Stock Island and Key West; although it may have been found in other hammock areas in the Lower Keys. The distribution has since been artificially extended by collectors, who have introduced them to Key Largo and the southernmost parts of mainland Florida. Orthalicus reses nesodryas has a broader range, occurring throughout the Florida Keys from Sugarloaf Key north. Orthalicus floridensis is the only Orthalicus species to occur naturally on the mainland, and is also found in the Keys. This species is known to occur in the National Key Deer Refuge.