Arthonia rubrocincta morphologically and anatomically fits the generic concept of Coniocarpon and is here transferred to the latter genus as Coniocarpon rubrocinctum. Specimens from southeastern United States and Bahamas were studied and the range of the species is found to extend north into North Carolina, USA and southeast to the Bahamas. Thatch palm (Coccothrinax argentata) is reported as a new phorophyte. An emended description based on examined material is presented for the species. Keywords: Arthoniales, morphology, distribution, taxonomy