Colurella C. obtusa μm Numappara marsh Kuroiso Tochigi, 2003 Colurella C. obtusa μm Watarase river Ashikaga Tochigi, 2004 Colurella C. obtusa ? μm Ukishima marsh Tsugaike highland Nagano, 2005 Colurella μm near Town Hall Shobu Saitama, 2004