Two new Falcaustra Lane, 1915 species (Nematoda: Kathlaniidae) from African pipids (Anura)

Abstract

Two new species of Falcaustra Lane, 1915 are the first to be reported in amphibians from mainland sub-Saharan Africa. Falcaustra puylaerti n. sp. occurs in hosts of the Xenopus (Silurana) tropicalis group in Sierra Leone, Togo and Nigeria. Falcaustra hinkeli n. sp. infects Xenopus (Xenopus) fraseri group hosts at localities in the Cameroon and the Democratic Republic of the Congo. Falcaustra hinkeli and F. puylaerti are probably sister species with respect to described congeners and can be differentiated from each other by the form of the cheilostomal structures, the morphometrics of the anterior body, and by a large difference in male spicule length. Both lack a precloacal pseudosucker and are separated from other Falcaustra spp. which share this characteristic by the pattern of male caudal papillae and by a cheilostomal ring with associated sclerotized elements and posteriorly directed projections. Evolutionary aspects of the host-parasite relationship are discussed. Although alternative hypotheses are possible, the distinctive cheilostomal morphology, the sister species relationship and the host specificity pattern of F. hinkeli and F. puylaerti are consistent with their having undergone an extended evolutionary association with the host genus.