Phylogeography of Rhabdias spp. (Nematoda: Rhabdiasidae) collected from Bufo species in Honshu, Shikoku, and Kyushu, Japan including possible cryptic species. (October 2022)

• Record Type: Journal Article
• Authors: Marcaida, Arvin Jet B.; Nakao, Minoru; Fukutani, Kazumi; Nishikawa, Kanto; Urabe, Misako
• Is Part Of: Parasitology international. Volume 90(2022)
• Publication Date: 2022-10
• Subjects: Rhabdias -- Bufo japonicus -- Cryptic species -- Phylogeography -- Nematoda -- Japan; Parasitology -- Periodicals; Parasites -- Periodicals; Parasitic Diseases -- Periodicals; Parasitology -- Periodicals; Parasitologie -- Périodiques; 571.99905
• DOI: 10.1016/j.parint.2022.102612
• Languages: English
• ISSNs: 1383-5769

Abstract

Abstract: The genus Rhabdias Stiles & Hassall, 1905 comprises lung parasites of amphibians and reptiles worldwide. In Japan, 9 species have been recorded, including Rhabdias incerta Wilkie, 1930 which has been reported only in Bufo species. In this study, to assess the diversity of R. incerta, we performed molecular analyses of Rhabdias species sampled from three species/subspecies of Japanese toads namely Bufo japonicus, B. japonicus formosus, and B. torrenticola, collected in various regions of Honshu, Shikoku, and Kyushu, Japan. DNA sequence divergence was compared using mtDNA (COI) and nuclear DNA (28S) to identify possible cryptic species. Morphological analysis was performed through light microscopy and scanning electron microscopy (SEM). The results revealed that Bufo spp. serve as hosts for at least three Rhabdias species. Morphologically, most samples were identified as R. incerta but with a longer body and larger buccal cavity than originally described. Rhabdias incerta appears to be specific to the genus Bufo and is further subdivided into two or three phylogroups based on subspecies divisions and biogeography of their host. Some Rhabdias specimens collected in this study resemble R. tokyoensis Wilkie, 1930, parasitic in hosts from the order Caudata, which suggests host switching. Both molecular and morphological analyses suggested the presence of undescribed and cryptic Rhabdias species within toads collected in Japan. This study was the first to molecularly characterize Rhabdias species in Japan, including novel sequences of R. incerta and two undescribed species. Graphical abstract: Unlabelled Image Highlights: Three species of Rhabdias were identified from 3 species/subspecies of Bufo in Japan. Rhabdias incerta is specific to Bufo and divided depending on its host. There are possibly 2 crpytic species of Rhabdias within the Japanese toads. First to generate DNA sequences from R. incerta and R. tokyoensis.