FURTHER OBSERVATIONS OF BLUNT-HOOKED PENTASTOMIDS BELONGING TO THE GENUS RAILLIETIELLA SAMBON, 1910 INFECTING HEMIDACTYLUS-BROOKII (SAURIA, GEKKONIDAE) IN AFRICA AND THE CARIBBEAN - COMPARISON WITH CLOSELY RELATED RAILLIETIELLA SPP FROM AN AFRICAN SKINK (MABUYA-PERROTETII)

Hemidactylus brookii, a gecko possessing great dispersal ability, has apparently spread from West Africa to the Caribbean and South America by natural rafting. The lungs of populations from West Africa and the Greater Antilles (Hispaniola and Puerto Rico) are heavily infected by raillietiellid pentastomids. Nigerian populations harbour two distinct species, frequently as concurrent infections, the males of which can be separated principally by marked differences in the morphology of the copulatory spicule. However one of these species cannot be reliably distinguished from Raillietiella teagueself, a common parasite of another highly successful coloniser, the Mediterranean gecko H. turcicus in Texas. The other more closely resembles R. frenatus, first described from the lungs of yet another itinerant gecko (H. frenatus) from south east Asia. Raillietiella spp. from both the Hispaniolan and Puerto Rican H. brookii haitianus populations, possess bluntly-rounded spicules of the R. frenatus type, although comparative posterior hook dimensions indicate that they are not closely related to it, or indeed to each other. They clearly comprise recognisably different geographical populations, but it remains unclear as to whether these are endemic or introduced. Both of the Caribbean species are left unnamed because we do not know what proportion of the observed intra- and interspecific variation is genetically based. Analysis of another raillietiellid population from an African skink (Mabuya perrotetii) is also included because it harbours two more species which are not easily distinguished from R. frenatus and R. teagueselfi. More refined diagnostic techniques, ultimately supplemented by life-cycle studies, are required to resolve these taxonomic problems.