Echiniscus japonicas (Morikawa 1951), a tardigrade about 0.3mm in length, belongs to Class: Heterotardigrada, Order: Echiniscoidea, Family: Echiniscidae. It is widely distributed in Japan, and characterized by the long claws, dorsal plates, and long lateral appendages (cirrus A). Majority of limno-terrestrial tardigrades are tolerant to extreme environments, such as extreme cold, heat, high pressure, vacuum, and radiation, and E. japonicus has high anhydrobiotic capabilities. Classification of E. japonicus from E. reticulatus is controversial, as reviewed in Ramazzotti & Maucci (1983).
