Additional files [RJEE Vol. 8 (1). 2023 – 2]

• Fig. 1. Areas of collection for D. rubidus specimens (Numerical designations are given in Table 1)
• Fig. 2. Pigmentation variations in D. rubidus (B. rubidus). At the top is an individual collected in the Western Siberia (chestnut brown pigmentation), whereas the one at the bottom is a worm collected in the North-Western Caucasus (purplish pigmentation)
• Fig. 3. Pigmentation variations in D. rubidus (B. rubidus). Worms from the sample collected in the North-Western Caucasus: almost evenly distributed purplish pigmentation at the top, weakened pigmentation at the bottom
• Fig. 4. Dissected specimens of D. rubidus (B. rubidus). Left: two pairs of spermathecae; Right: complete absence of spermathecae
• Fig. 5. Phylogenetic tree built based on sequences of cox1 of D. rubidus using the maximum likelihood method. Key: E#### means sequences obtained; _r means D. r. rubidus, _t means D. r. tenuis; _s means D. r. subrubicundus. Numbers above the branches indicate bootstrap support for the maximum likelihood method / Bayesian a posteriori probabilities