Folsomia atropolaris Potapov & Babenko 2000

Folsomia atropolaris Potapov & Babenko, 2000

Discussion. A characteristic species of F. regularis complex (' quadrioculata ' group) due to 3+3 laterodistal chaetae on VT and basal ms on Ant.III missing. In the Arctic this species is usually mottled grey or even almost black while the specimens from Buryatia are less pigmented. They also never have ocelli which are often present (rudimentary) in the northern populations. The place of the missing ocellus is always well marked by dark pigmentation.

In the Northern Barguzin Range another, probably new species, closely related to F. atropolaris, was collected. It has no basal ms on Ant.III (shared with F. a t ro p o l a r i s), 4+4 laterodistal chaetae on VT (vs. 3+ 3 in F. atropolaris), and shows very characteristic chaetotaxy of anterior side of manubrium with 3+3 chaetae arranged as 1+1 subapical and 2+ 2 in more proximal part. More material is needed to describe this new species.

Distribution and ecology. A rather common species in larch taiga forests at the upper flow of the Barguzin River (Northern Buryatia) (Fig. 1: loc. 8), especially on damp and cold slopes. The species is widely distributed in Siberia but so far does not occur in southern areas (Babenko & Fjellberg 2006).