Echiniscus testudo is a cosmopolitan species of tardigrade.
The species was described by Louis Michel François Doyère in 1840; he placed it in the genus Emydium.
G. Ramazzotti and W. Maucci classified E. filamentos mongoliensis as a synonym of E. testudo in 1983; this was followed by other tardigradologists. In 2017, Piotr GÃÂ siorek and colleagues restored it as a distinct taxon and elevated it to species level: E. mongoliensis.
GÃÂ siorek and colleagues also classified E. filamentosus and E. glaber as junior synonyms of E. testudo.
It is found throughout most of the Palaearctic, and has been recorded in all continents except Antarctica and Australia. Most reports are Holarctic. Locations where it has been recorded include: Denmark, Egypt, the Faroe Islands, France, Germany, Greece, Greenland, Israel, Italy, Morocco, Iberia, Mongolia, and China.
Doyère based his description off specimens collected in Paris. The neotype designated by Gàsiorek and colleagues was collected in Paris's Montmartre Cemetery. The type localities of the junior synonyms E. bellermanni and E. inermis are both in Germany: the former is Greifswald, and the latter is the Taunus mountains near Frankfurt.