title: The life cycle and molecular phylogeny of a gorgoderid trematode recorded from the mussel Nodularia douglasiae in the Yodo River, Japan.
abstract: In 2009, a novel larval trematode of the family Gorgoderidae was found in the gonads of Nodularia douglasiae (Unionidae) from the lower reaches of the Yodo River, Osaka Prefecture, Japan. This is the first collection of trematodes in a unionid mussel in Japan. We investigated the morphology and life cycle of the trematode, and conducted a molecular phylogenetic analysis with other gorgoderid species, both those collected in the Yodo River water system and those reported in the literature. Immature adult worms were obtained from the ureters of the common carp Cyprinus carpio, the first known instance of a gorgoderid from these fish in Japan. Morphological characteristics and molecular data show that it belongs to the subfamily Gorgoderinae (genus Phyllodistomum sensu lato). Regarding the morphology, first intermediate host, and the infection site of adult worms, it resembles Phyllodistomum elongatum Nybelin, 1926 from Europe, but no comparable molecular data exist for Ph. elongatum. Three cytochrome c oxidase subunit I haplotypes were detected in the specimens analyzed, suggesting that the present species is indigenous to the Yodo River water system. The 28S ribosomal DNA data showed that this species is a member of the clade consisting of Ph. cf. symmetorchis, Ph. folium, Pseudophyllodistomum and Xystretrum. However, its phylogenetic position within the clade differs between the maximum likelihood and maximum parsimony trees, and the sister species of the present species remain unclear.
authors.affiliation: Department of Ecosystem Studies, School of Environmental Science, The University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga 522-8533, Japan. Electronic address: urabe@ses.usp.ac.jp.
authors.forename: Misako
authors.initials: M
authors.lastname: Urabe
authors.affiliation: Aquatic Life Conservation Center, Research Institute of Environment, Agriculture, and Fisheries, Koyamotomachi 10-4 Neyagawa, Osaka 572-833, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ishibashi
authors.affiliation: Aquatic Life Conservation Center, Research Institute of Environment, Agriculture, and Fisheries, Koyamotomachi 10-4 Neyagawa, Osaka 572-833, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Uehara
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000469:parasitology; D002347:Carps / Q000469:parasitology; D004275:DNA, Ribosomal; D005393:Fish Diseases / Q000469:parasitology; D007564:Japan; D007814:Larva / Q000235:genetics; D008018:Life Cycle Stages; D010802:Phylogeny; D012339:RNA, Ribosomal, 28S / Q000235:genetics; D045483:Rivers; D014200:Trematoda / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D014201:Trematode Infections / Q000469:parasitology / Q000662:veterinary; D049876:Unionidae / Q000469:parasitology*
chemical_list: D004275:DNA, Ribosomal; D012339:RNA, Ribosomal, 28S
keywords: Cyprinus carpio; Life cycle; Molecular phylogeny; Nodularia douglasiae; Subfamily Gorgoderinae