The centipede genus Arthrorhabdus Pocock, 1891, in the Western Hemisphere: potential occurrence of A. pygmaeus (Pocock, 1895) in Belize (Scolopendromorpha: Scolopendridae: Scolopendrinae)

The scolopendrid centipede genus Arthrorhabdus Pocock, 1891, comprises 6 species: A. formosus Pocock, 1891, the type species, occurring in southern Africa (Mpumalanga, Free State, Western and Northern Cape Provinces, South Africa, and southern Namibia); A. somalus Manfredi, 1933, in Somalia and Yemen; A. jonesii Verhoeff, 1938, from southern India (Kerala Province); A. mjobergi Kraepelin, 1916, and A. paucispinus Koch, 1984, in Australia (Western and South Australia, Northern Territory, and Queensland); and A. pygmaeus (Pocock, 1895), in the south central and southwestern United States, Mexico, and, potentially, Belize. This sporadic occurrence suggests that the genus is polyphyletic, and the monotypic synonym, Arthrorhabdinus Verhoeff, 1907, is available for pygmaeus , which is not referrable to another established genus. Arthrorhabdus spinifer (Kraepelin, 1903), known only from Belém, Pará State, Brazil, is transferred to Rhoda Meinert, 1886, thereby constituting a new combination. Sixteen new localities are reported for A. pygmaeus , 14 in Mexico and 2 in the U.S.; a specimen from Belize, intercepted in quarantine in Miami, suggests occurrence in this country. The 2 U.S. sites, in Cameron County, Texas, and Pima County, Arizona, extend the generic and specific ranges around 400 miles (640 km) to the southeast and west, respectively. In Mexico, A. pygmaeus ranges southward through the mainland, possibly excluding the Yucatan Peninsula, and also inhabits the southern half of Baja California Sur (BCS). Its apparent absence from the rest of the Baja peninsula suggests that the BCS populations may result from rafting across the Gulf of California from Sinaloa, where the species occurs.