群馬県菅沼におけるウチダザリガニPacifastacus leniusculusと共生ヒルミミズ および貝形虫の新記録

A new population of the non-indigenous signal crayfish, Pacifastacus leniusculus, was recorded from Lake Sugenuma in Gunma Prefecture, central Japan. A survey conducted in 2019 confirmed that the signal crayfish is established and widely distributed in the lake. Sathodrilus attenuatus(Annelida, Clitellata, Branchiobdellida)and Uncinocythere occidentalis (Arthropoda, Crustacea, Ostracoda)were newly recorded in the Prefecture, as ectosymbionts on the crayfish. The branchiobdellidan fauna suggests that the present crayfish and symbionts in Lake Sugenuma are derived from Hokkaido populations or their descendants. [ABSTRACT FROM AUTHOR]