Redescription of two subterranean species of the genus Oncopodura Carl & Lebedinsky, 1905 (Hexapoda, Collembola) from the Balkan Peninsula

We provide redescriptions of two subterranean species of the genus Oncopodura inhabiting caves of the Balkan Peninsula, namely O. cavernarum Stach, 1934 and O. jugoslavica Absolon & Kseneman, 1932, partly based on specimens from type localities. Oncopodura cavernarum differs from other species of the genus by a combination of the following characters: single lobe in PAO, unguis elongated, ungual basal lamella shorter than or equal to half the length of the unguis, mucro with 4 teeth and 2 basal scales, and pattern of hooks on dens: 1 dorsointernal hook on basal part, and 1 dorsoexternal and 1 dorsointernal hook on distal part. Oncopodura jugoslavica can be distinguished from other congeners by PAO with 4 equally short lobes, unguis elongated, ungual basal lamella longer than half the length of the unguis, mucro with 4 teeth and 2 basal scales, and pattern of hooks on dens: basal part with 1 dorsointernal hook, and distal part with 1 dorsoexternal and 2 dorsointernal hooks. In both species, the modification of the foot complex shows a moderate level of troglomorphy. Regarding the geographical distribution, these two Dinaric Oncopodura species occur in allopatry: O. cavernarum has north-western and central merodinaric distribution range, while O. jugoslavica is characterized by a south-eastern merodinaric distribution. For both redescribed species, tables with diagnostic characters of morphologically similar congeners are provided.