Potamothrix paramoldaviensis Cui & Wang 2012

Specimen incomplete, length > 4.4 mm, diameter at XI about 0.7 mm, segments > 13. Clitellum inconspicuous. Chaetae (Fig. 2A–B) all bifid, 4–6 per bundle dorsally, 3–6 per bundle ventrally, 80–120 µm long, 2.0–2.6 µm thick, upper tooth longer and thinner than lower. Spermathecal chaetae (Fig. 2D) one per bundle in posterior to middle of X, entally embedded in glandular sacs, 145–160 µm long, 4.0–4.5 µm thick, with curved ental part, and grooved ectal part. Penial chaetae (Fig. 2C, F, pc) slightly different to other ventral chaetae, 1–2 per bundle in postero-XI, 70–74 µm long, 2.0–2.4 µm thick, upper tooth as long as, but thicker than lower tooth. Male pores paired in line with ventral chaetae in postero-XI, immediately anterior to penial chaetae. Spermathecal pores paired in line with ventral chaetae in posterior to middle of X, immediately anterior to spermathecal chaetae. Pharyngeal glands in II–III. Chloragogen cells from VI onwards. No coelomocytes. Male genitalia (Fig. 2F) paired. Vasa deferentia (Fig. 2F, vd) very short, 27–38 µm long, 16–20 µm wide, entering atria apically. Atria (Fig. 2F, at) 1050–1130 µm long, 38–90 µm wide, tubular and rather homogenous throughout, with thin outer muscular layer and thick inner epithelium. Prostate gland small, attached proximally to atrium. Penis absent. Spermathecae ducts (Fig. 2E, sd) 345–360 µm long, 38–70 µm wide, ampullae (Fig. 2H, sa) pear-shaped, 420–430 µm long, maximally 230–250 µm wide. Spermatozeugmata (Fig. 2H, sz) 6–9 in each ampulla, about 300–640 µm long.

Known only from its type locality, Yunnan Province, China; freshwater lake, 78 m depth, water temperature less than 16 °C, fine clay.