Long-anticipated new records of an ectosymbiotic branchiobdellidan and an ostracod on the North American red swamp crayfish, Procambarus clarkii (Girard, 1852) from an urban stream in Tokyo, Japan

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Two North American ectosymbionts, a cambarincolid branchiobdellidan, Cambarincola mesochoreus, and an entocytherid ostracod, Ankylocythere sinuosa, were recorded for the first time in Japan, on the red swamp crayfish, Procambarus clarkii, from an urban stream in Tokyo. Although the immediate origin of the hosts and ectosymbionts is unknown, it is highly probable that they were recently imported into Japan. A single C. mesochoreus was also found on an alien atyid shrimp, Neocaridina davidi, in the same stream as the infected Pr. clarkii. This demonstrates the possibility that C. mesochoreus may find this shrimp to be a new potential host.