A Species of Anemina (Bivalvia: Unionidae) from Shizuoka Prefecture, Central Japan

Abstract

We found Anemina species in a canal in Yaizu City, Shizuoka Prefecuture, central Honshu, Japan. In this paper, we attempt to determine its taxonomic position by means of molecular phylogenetic analysis and morphological observation. The shell morphology of Anemina sp. matches well that of Anemina euscaphys (Heude, 1879), which was described from the lower Yangtze River basin of China. In the molecular phylogenetic analysis, however, Anemina sp. clustered with the reference sequences of not only Anemina euscaphys but also Anemina arcaeformis (Heude, 1877) and Anemina globosula (Heude, 1879) so that we could not determine which species it belongs to. Anemina sp. is known to occur in China, South Korea and northern Kyushu Island in Japan, and this is the first record from Honshu Island. It was found in a canal flowing from eel farms (Anguilla japonica) in Shizuoka Prefecture, so it was possibly introduced from elsewhere together with imported juvenile eels ("glass eels"). On the other hand, there is also a possibility that Anemina sp. in Shizuoka Prefecture is indigenous and has until now been confused with other similar species [e.g., Sinanodonta lauta (Martens, 1877), Beringiana japonica (Clessin, 1874) or Beringiana fukuharai Sano, Hattori & Kondo, 2020].