Sachsia putridicola n. sp. (Rhabditida: Diplogastridae), isolated from an Onthophagus dung beetle (Coleoptera: Scarabaeidae) from Tsukuba, Japan

An undescribed Sachsia species (Diplogastridae) was isolated from a dung beetle, Onthophagus sp. cf. atripennis, and the species is described here as Sachsia putridicola n. sp. The new species is characterised by its cheilostom; anterior part forming a cuticular ring, posterior part in the form of a thin-walled tube; an anisotopic gymnostom, a metastegostom with dorsal small tooth and no subventral armature, and setiform male genital papillae with the arrangement . Sachsia putridicola n. sp. is typologically similar to two previously described congeners, Sachsia zurstrasseni and Sachsia postpapillata, but can be readily distinguished by its anisotopic gymnostom (vs isotopic gymnostom in the two nominal species) and the direction of the anterior three pairs of genital papillae, which are directed sublaterally in the new species (vs second or third pair directed sublaterally in S. zurstrasseni and S. postpapillata, respectively). Phylogenetically, the new species is close to Eudiplogasterium evidentum, not S. zurstrasseni. Based on the typological and phylogenetic characters, the status of S. zurstrasseni is discussed.