Morphology of adult and juvenile instars of Galumna obvia (Acari, Oribatida, Galumnidae), with discussion of its taxonomic status

The adult instar of the oribatid mite, Galumna obvia (Berlese, 1914), is redescribed in detail, on the basis of specimens from Finland. The morphology of juvenile instars of G. obvia is described and illustrated for the first time, and compared to that of other species of the family Galumnidae. The position of the insertion of the lamellar seta in adults proved variable in studied European populations, being either on or medial to the lamellar line. Since the genera Galumna and Pergalumna are currently distinguished only by the relative positions of the seta and line, specimens of G. obvia in some populations show an intermediate situation between other studied Galumna species – with lamellar seta on or lateral of lamellar line – and Pergalumna with lamellar seta at a distinct distance medially of lamellar line. A detailed reevaluation of the two genera is needed.