Nipponomysella subtruncata (Heterodonta: Galeommatoidea), symbiotic with the sipunculan worm Siphonosoma cumanense was collected from Uranouchi Inlet, Tosa Bay, Kochi Prefecture, Japan. This clam has been designated as one of the nearly threatened species both by the Ministry of the Environment and by the Japanese Association of Benthology. The locality was a small intertidal sandy mud flat on the southern coast of the Inlet. This is the first record of the clam from southern part of Shikoku Island.
