A New Species of Sphaerospora Thélohan, 1892 (Myxozoa: Myxosporea: Bivalvulida) From the Japanese Rice Frog Fejervarya kawamurai: The First East Asian Record of Anuran-Parasitic Sphaerosporids.

Myxosporean parasites have been identified in amphibians globally; however, in Japan, no amphibian-infecting myxosporeans have been formally recorded. Thus, in this study, 20 native Japanese frog species were surveyed to clarify the diversity of myxosporeans that infect amphibians. A survey of 102 anurans representing 20 species across six families collected in Japan revealed the presence of a myxosporean belonging to the genus Sphaerospora that parasitizes the kidneys of the Japanese rice frog, Fejervarya kawamurai. The myxosporean is described herein as a new species based on its distinct morphological characteristics and phylogenetic position. Spores are spherical to subspherical with an overall dimension of 11.1 (10.2-12.2) × 11.5 (9.3-14.0) µm. The polar capsules are spherical, with a diameter of 3.3 (2.5-4.3) µm. Typical spores possess a characteristic caudal appendage. This discovery is considered the first record of anuran-parasitic Sphaerospora in East Asia and the fifth global record of a frog-parasitic species in this genus. Phylogenetic analysis based on partial SSU rDNA sequences unequivocally placed the new species within a well-supported monophyletic clade of anuran-parasitic Sphaerospora, comprising taxa distributed across the Palaearctic (Asia and Europe), Afrotropical, Nearctic, and Neotropical realms.