Metazoan parasites of anurans from the Vhembe area, Limpopo, South Africa

Abstract

Amphibians were the first vertebrate group to appear on land about 350 m.y.a and have diversified and colonized all suitable continents and islands. Amphibians are hosts to vast numbers and an astonishing diversity of parasites, representing all parasitic groups. These include protozoans, nematodes, acanthocephalans, monogeneans, digeneans, cestodes, leeches and mites. This impressive parasite diversity can be explained by the fact that amphibians are closely associated with water, which facilitates parasite transmission and they play the middle role in food chains - being both predators and prey. Amphibian parasitic fauna is generally poorly understood and understudied; this is especially true in southern Africa, where over 170 amphibian species have been identified. This study will show that we discovered a vast diversity of parasites in 22 different anuran species, from the previously unstudied area. A large number of parasites were found using morphological, molecular and statistical approaches and several of them appear to be distinct from all known species and are, most likely, new to science. During this project 269 specimens of frogs representing 22 species were collected, dissected and studied for parasites. This research revealed 35 species of metazoan parasites, including 24 nematode species, two cestode species, three trematodes, three monogeneans, one acanthocephalan, one mite and one annelid species. The most infected amphibian species were the common river frog, Amietia delalandii and the African clawed frog, Xenopus laevis which harboured six and five helminth species, respectively. Nematodes were the most common parasites, accounting for 69% of the faunal community (24 of 35 species). We discovered numerous species that are morphologically and genetically different in a rather small research region and within only 22 species of anurans. Understanding and researching host-parasite interactions in nature will help to close the knowledge gaps in disease and community ecology. Parasites are everywhere, diverse, and inventive and we believe that incorporating them into basic biological research will be a significant stride forward for decades to come.