( Fig. 8)
Histiophorus brachyurus Dubinina, 1964: 125, fig. 10, 1 – 4
Schizocarpus brachyurus, Fain & Lukoschus 1985: 66; Dubinina et al. 1993: 451; Bochkov & Dubinina 2011: 57, figs. 2 B, 3 B; Bochkov et al. 2012: 55
Schizocarpus parabrachyurus Fain and Lukoschus, 1985: 45, figs. 12, 14, 15; syn. nov.
Schizocarpus intercalatus Fain and Lukoschus, 1985: 46, figs. 13, 16, 17; Bochkov et al. 2012: 55; syn. nov.
Material examined. 8 males ( ZISP AVB- 2012 -0203-042, # 1-8) ex Castor fiber tuvinicus [beaver # 2, sample 11], RUSSIA: Tuva, Todzhinskii District, upstream water of Azas River, 52 º 25 ’N, 96 º 38 ’E, 9 October 2011, coll. A.P. Saveljev; 1 male ( ZISP AVB- 2012 -0203-043), beaver # 4, sample 4, downstream of Azas River, 52 º 32 ’N, 97 º 15 ’E, 16 October 2011, coll. A.P. Saveljev.
Microhabitat. Anterior legs, one mite from anterior dorsum.
Distribution. Recorded from C. f. orientoeuropaeus from Russia (Voronezh Reserve) ( Dubinina 1964), from the Eurasian beaver (undetermined subspecies) from unknown locality in Europe ( Fain & Lukoschus 1985), from C. f. belorussicus from Poland (Suwałki) ( Bochkov et al. 2012), and from C. f. tuvinicus from Tuva (Azas River) (present paper).
Remarks. Fain and Lukoschus ( 1985) described two species closely related to S. brachyurus: S. intercalatus Fain and Lukoschus, 1985 from a Eurasian beaver (undetermined subspecies) from an unknown locality in Europe and S. parabrachyurus Fain and Lukoschus, 1985 from C. f. albicus from Germany (Elba River). These three species slightly differed from each other by the shape of the adanal shields and positions of setae ad 1 and ps 1. The type specimens of S. brachyurus were not available to Fain and Lukoschus ( 1985) and the original description of this species by Dubinina ( 1964) did not include some fine but important details (see redescription in Bochkov & Dubinina 2011). We examined a series of specimens from C. f. belorussicus and C. f. tuvinicus, which could be assigned to these three forms, and have come to the conclusion that the “species” described by Fain and Lukoschus ( 1985) represent extreme morphological variants of the above mentioned characters and actually belong to one species. The examples of significant variability of some characters in several Schizocarpus species were described by Fain and Whitaker ( 1988) and Bochkov et al. ( 2012). We consider here S. parabrachyurus syn. nov. and S. intercalatus syn. nov. as junior synonyms of S. brachyurus.