Paramphistome digeneans from shape Xenopus species (Pipidae) in Africa: taxonomy, host-specificity and biogeography

Abstract

The taxonomy, host range and geographical distribution of paramphistome digeneans from Xenopus spp. in sub-Saharan Africa are reviewed. Two representatives of Progonimodiscus Vercammen-Grandjean, 1960 are recognised, both of which are narrowly or primarily specific to Xenopus. An analysis of morphometric and meristic characters indicated geographical variation in Progonimodiscus doyeri (Ortlepp, 1926), with two allopatric forms showing significant, but continuous, variation in testis size and vitelline follicle number. P. colubrifer n. sp. is distinguished from P. doyeri by the form of muscular elevations on the acetabulum accessory peduncle. It infects Xenopus ( Silurana) tropicalis-like toads from lowland tropical rain forest zones in Nigeria, Togo and the Ivory Coast, while P. doyeri occurs in hosts of the subgenus Xenopus from a wide variety of biotypes. Previous literature records indicate the presence of the southern P. doyeri morphological variant in X. laevis laevis in South Africa and Zimbabwe and the northern variant in X. l. victorianus, X. fraseri aff. and X. muelleri in the Democratic Republic of Congo, X. wittei in Uganda and the Democratic Republic of Congo, and the ranid Conraua crassipes in Cameroon (the only record of Progonimodiscus from a non-pipid host). New host and/or geographical records for this species are of the northern form in X. l. victorianus, X. l. bunyoniensis and X. vestitus in Uganda, X. l. sudanensis in Cameroon, X. borealis in Kenya, X. pygmaeus in the Democratic Republic of Congo, X. fraseri aff. in Cameroon, X. wittei aff. in the Democratic Republic of Congo and X. muelleri in Cameroon and Nigeria. While the geographical limits of the two P. doyeri variants are not known with precision, existing data are consistent with a “turnover” in the region of 15°S, where a notable discontinuity occurs in the distributions of other Xenopus parasites. Species of Diplodiscus Diesing, 1836 in Xenopus hosts are rare. Diplodiscus peregrinator n. sp. was recovered from X. tropicalis at a single locality in the Ivory Coast and distinguished by a combination of body size, egg size, genital pore position and acetabulum morphology. D. fischthalicus Meskal, 1970 was not found during the present study.