Folsomia najtae n. sp. (Collembola: Isotomidae) – a new species with ‘mobile’ forms from the Far East of Russia

Folsomia najtae n. sp. is described from the southern part of Sikhote-Alin Range (Far East, Russia). It is characterized by 6 + 6 ommatidia, a full set of ms-chaetae on body tergites, long accp3 s-chaetae on the fifth abdominal segment, four posterior chaetae on dens, and dimorphism of juvenile specimens. The properties that define the ‘mobile’ form are protruding cornea of ommatidia and tuberous long dens. The closely related species F. orientalis Martynova, 1977 and F. setula Christiansen & Tucker, 1977 are redescribed basing on the material from North-East of Asia and East of North America, respectively.