New species of Rhabdias (Nematoda: Rhabdiasidae) from afrotropical anurans, including molecular evidence and notes on biology.

Abstract

Despite the small sample size the diversity of Rhabdias Stiles et Hassall, 1905 from anurans in the Afrotropical region was found to be high. Four species were collected from four localities, one in South Africa, two on Cameroonese mountains and one in Madagascar: Rhabdias picardiae sp. n. from the bufonid Amietophrynus gutturalis (Power); Rhabdias ohlerae sp. n. and Rhabdias tanyai sp. n. from the arthroleptids Leptopelis brevirostris (Werner) and Astylosternus rheophilus Amiet, respectively; and Rhabdias vencesi sp. n. from the mantellid Boophis madagascariensis (Peters). Distinctive characters between these species are numerous and obvious, based on body size, shape and size of the buccal capsule, arrangement of head papillae, and shape and size of the oesophagus and intestinal apex. Molecular data based on 500 bp of 12S rDNA and 600 bp of coxl of three of the four species are presented. Rhabdias vencesi resembles Rhabdias madagascariensis Chabaud, Brygoo et Petter, 1961 from an African ptychadenid introduced on Madagascar, but differs in body size and head morphology. The remaining new species are clearly distinct from those previously known from Afrotropical anurans. Outside the Afrotropics, some Rhabdias species present characters similar to those observed in the new species, but they all differ in various other characters. No clear correlation was seen between Rhabdias species and families of anuran hosts in this region. However, the narrow buccal capsule seen in Rhabdias species from Afrotropical lissamphibians opposes them to the majority of Rhabdias parasitic in chamaeleonids. Furthermore, the infective larva of R. vencesi has a conical pointed tail, while those of Rhabdias from chameleons have a rounded tail tip ornated with a few buds.