A revision of the Pharyngodoninae, nematodes of frogs and lizards

Abstract

This revision of 4 pharyngodonid genera, Parathelandros, Skrjabinodon, Spauligodon, and Pharyngodon, recognises 84 species that form a monophyletic group within the Pharyngodonidae. This monophyletic group is here given subfamily status, namely the Pharyngodoninae. Species descriptions, host and locality records, and synonyms are given for each species in the subfamily. Type or voucher specimens were examined for 49 of the 84 species, and my observations are recorded, amending descriptions where appropriate. Keys are provided for the genera in the subfamily, and for the species in each genus. Parathelandros is restricted to amphibia and to Australia, Papua New Guinea, and Japan. However, Skrjabinodon, Spauligodon, and Pharyngodon are parasites of lizards and are widespread. This broad distribution reflects the equally broad distribution of the lizard families that host the 3 genera. For example, the Gekkonidae, which host more pharyngodonine species than any other lizard family, are also the most widespread lizard family. Additionally, the pharyngodonine fauna of the Gekkonidae comprises equal numbers of Skrjabinodon, Spauligodon, and Pharyngodon species. Therefore, the 3 genera have very similar distributions. Cladistic analysis of the Pharyngodoninae, using the Thelastomatidae as an outgroup, shows that Parathelandros and Skrjabinodon are more primitive than Spauligodon and Pharyngodon. Thus, the development of caudal alae is a derived character, as is the possession of pedunculate anal and caudal papillae. This finding is a reversal of previous theories of pharyngodonine evolution...