First record of the invasive American tapeworm Ophiotaenia saphena (Cestoda: Proteocephalidae) in the Tokyo daruma pond frog Pelophylax porosus porosus in Japan.

Adult proteocephalid tapeworms of the genus Ophiotaenia (Cestoda: Proteocephalidae) were recovered from the endemic Japanese amphibian species, Pelophylax porosus porosus (Amphibia: Ranidae) from Tochigi, Japan. As a result of molecular analyses based on the 28S ribosomal RNA and cytochrome c oxidase subunit I genes, these worms were identified as Ophiotaenia saphena, a species native to North America. Their morphological features were also consistent with those of O. saphena. This species is presumed to have been introduced into Japan with the American bullfrog, Lithobates catesbeianus (Ranidae). This study presents the first record of O. saphena in Japan and documents a new host record for this species.