Speciation of Protopolystoma Bychowsky, 1957 (Monogenea: Polystomatidae) in hosts of the genus shape Xenopus (Anura: Pipidae)

The taxonomy, geographical distribution and hostrange of the polystomatid genus ProtopolystomaBychowsky, 1957 are reviewed. P. xenopodis(Price, 1943) and five new species are recognised,which occur in clawed toads ( Xenopus spp.)throughout subsaharan Africa. Of the two clawed toadsubgenera, Xenopus and Silurana, only theformer is infected. Protopolystoma spp. aredifferentiated by morphological variation of the gut,large hamulus and penis armature. P.xenopodis is found in Xenopus laevis subspeciesin South Africa, Transkei, Zimbabwe, DemocraticRepublic of Congo (D.R.C.), Rwanda, Uganda, Kenya andCameroon ( X. l. poweri and X. l.sudanensis are new host records). It also occurs inintroduced populations of X. l. laevis in theUnited States (southern California) and United Kingdom(South Wales). In subsaharan Africa the speciesdisplays significant, but continuous, geographicalvariation of penis spine size between southernpopulations in X. l. laevis and those in morenortherly host subspecies. Data on the natural hostrange of this parasite were complemented by anexperimental study of host-specificity in the southernform. This can produce patent infections in X.l. victorianus and X. gilli, but not X.wittei nor X. (Silurana) tropicalis. P.simplicis n. sp. is endemic to central and eastAfrican areas, infecting X. laevis subspecies ineastern D.R.C., Rwanda, Uganda and western Kenya, X. wittei-like hosts in eastern D.R.C., westernUganda, Rwanda and Burundi, X. vestitus inwestern Uganda and Xenopus sp. at Nairobi,Kenya. P. ramulosus n. sp. occurs in X.fraseri-like toads in eastern D.R.C. (Gabon andCameroon are also possible literature records), and P. fissilis n. sp. is found in X. fraseri-and X. wittei-like species in Cameroon andeastern D.R.C., and in southern Rwanda, respectively. Two Protopolystoma taxa are found in X.muelleri populations now suspected to representdistinct species: P. occidentalis n. sp. occursin X. muelleri (western form) in Ghana, Togo,Nigeria and Cameroon, while P. orientalis n. sp.is found in X. muelleri (eastern form) in SouthAfrica, Zimbabwe and Tanzania. The allopatricallydistributed species P. ramulosus, P.simplicis, P. occidentalis and P.orientalis form a relatively homogenous grouping withsome interspecific morphological overlap. These taxaare distinguished from P. xenopodis by penisspine morphology and from P. fissilis by hamulusroot form and aspects of gut morphology. Unidentified Protopolystoma sp. have been recorded in X. clivii in Ethiopia, X. fraseri aff. inCameroon and Xenopus sp. in Kenya and Tanzania. At some localities, single host species were infectedby two representatives of Protopolystoma. P. fissilis was recorded in eastern D.R.C. with P. ramulosus, with Protopolystoma sp. inCameroon in X. fraseri-like hosts and with P. simplicis in X. wittei-like hosts in Rwanda. P. xenopodis co-occurred with P. simplicisin X. laevis subspecies through central and eastAfrica.