Host-specificity and distribution of cephalochlamydid cestodes: correlation with allopolyploid evolution of pipid anuran hosts

The taxonomy and distribution of cephalochlamydid cestodes are reviewed. Th is group is primarily specific to pipid anurans and occurs naturally across sub-Saharan Africa. Paracephalochlamys gen. nov. has two large lateral tes tes (sometimes doubled or absent on one side) on the anterior margin of eac h segment, while Cephalochlamys Blanchard, 1908 has three to 23 small teste s scattered in lateral fields. Paracephalochlamys papilionis sp. nov. infec ts Pseudhymenochirus merlini in Sierra Leone. The distribution of Cephaloch lamys species is inferred from the previous literature and numerous new rec ords. Cephalochlamys namaquensis (Cohn, 1906) occurs in Xenopus laevis laev is in Namibia, South Africa, Lesotho and Zimbabwe, X. l. poweri (new host r ecord) in Zambia and the Democratic Republic of Congo (D.R.C.), X. I. victo rianus in Kenya, Uganda, Rwanda and D.R.C., X. I. sudanensis (new host reco rd) in Cameroon and Sudan, and the ranid anuran, Rana angolensis, in Zimbab we. Anthropogenic dispersal of C. namaquensis, together with X. I. laevis, has occurred to localities in the south-western United States and Isle of W ight, U.K. Cephalochlamys compactus sp. nov., differentiated from C. namaqu ensis by a less well developed median ovarian cavity and more compact vitel larium, occurs in Xenopus muelleri in Togo, Ghana, Nigeria, Cameroon, D.R.C ., Zimbabwe and South Africa, X. borealis in Kenya, X. clivii in Ethiopia, R. angolensis in Ethiopia and R. occipitalis in Nigeria. Cephalochlamys rep resentatives of uncertain specific status have been recorded in X. gilli (n ew host record) in South Africa, X. pygmaeus and X. fraseri-like hosts (new host records) in the D.R.C., X. tropicalis (new host record) in Nigeria an d R. occipitalis in Gabon. Despite the ability of some species to infect di stantly related amphibians, the distribution of cephalochlamydid taxa among st their principal hosts, pipids, can be related to the allopolyploid evolu tion of this anuran family.