Macrothrix laticornis Fischer

Macrothrix laticornis is a small species having a shape which may resemble S. serricaudatus. Its carapace is more or less circular, and the anterior part of its head is less pointed than the head of M. hirsuticornis. The oscellus is not as close to the eye as in M. hirsuticornis. The first pair of antennae are relatively robust and have bunches of setaes close to the tip. The square shape of its postabdomen, which is normally hidden by the carapace, is a useful criterion to separate M. laticornis from other species within the same family. Its postabdominal claw is especially small. It has a grey to a bright greenish colour.

Female: Length 0.3–0.9 mm

Male: Length 0.3–0.4 mm

M. laticornis is a littoral species which is found in a limited number of water bodies. All except one situated in the area east and south-east of Oslo. It is found in waterbodies of varying size, including both ponds and large lakes, all situated below 500 m a.s.l.  pH varies between 5.4 and 7.5, while conductivity is within the range 1.4–9.7 mS/m.