Potamothrix parabedoti Cui & Wang 2012

Two complete specimen 8.9–19.8 mm long (Holotype: 8.9 mm), with 36–131 segments (Holotype: 36), diameter at XI about 0.8 mm. Prostomium conical. Clitellum inconspicuous. Dorsal chaetae (Fig. 3B) of II (II–IV) bifid only, 7–8 per bundle, 100–145 µm long, 2.8–3.0 µm thick, upper tooth longer and thicker than lower. Dorsal bundle of III (V)-IX 4–8 hair chaetae and 5–8 bifid chaetae per bundle; plumose hair chaetae (Fig. 3A), 250–300 µm long, 2.8–3.2 µm thick basally; pectinate bifid chaetae (Fig. 3C–D), 140–150 µm long, 2.8–3.2 µm thick, with 1–3 intermediate teeth, upper tooth slightly longer and thinner than lower (usually bifurcated), or equally long. Dorsal bundles of posterior segments 2–4 hair chaetae and 3–4 bifid chaetae per bundle, shorter and thinner than those of anterior segments, hair chaetae 200–240 µm long, bifid chaetae 100–120 µm long, 2.6–2.8 µm thick. Ventral chaetae (Fig. 3E–F) bifid, 6–10 per bundle anteriorly, 100–150 µm long, 2.8–3.0 µm thick; 3–5 per bundle in postclitellar segments, 100–125 µm long, 2.4–2.6 µm thick, all with tooth similar to dorsal chaetae in II–IV. Spermathecal chaetae (Fig. 3I) one per bundle in middle to posterior of VIII or IX, entally embedded in glandular sacs, about 125–140 µm long, 4.0 µm thick, ental end strongly curved, with ectal part grooved. Penial chaetae absent. Male pores paired in line with ventral chaetae, middle to posterior of IX or X. Spermathecal pores paired in line with ventral chaetae, middle of X, immediately anterior to spermathecal chaetae. Pharyngeal glands in II. Chloragogen cells from IV or V onwards. No coelomocytes. Male genitalia (Fig. 3G) paired. Vasa deferentia (Fig. 3G, vd) 45–70 µm long, 18–24 µm wide, entering atria apically. Atria (Fig. 3G, at) 880 µm long, 44–80 µm wide, tubular and rather homogenous throughout, with thin outer muscular layer and thick inner epithelium. Prostate gland absent. Soft part of penis (Fig. 3G, pe) cylindrical and tapering ectally, 80–100 µm long, basally 45–60 wide, ectally 25–36 wide, enclosed in penial sacs. Penial sac (Fig. 3G, ps) 80–130 µm long, 72–92 µm wide, with muscular layer 2–4 µm thick. Spermathecae (Fig. 3H) in VIII–XIII or VIII, ducts (Fig. 3H, sd) 500–568 µm long, 74–95 µm wide, ampullae (Fig. 3H, sa) elongated, 470–1280 µm long, maximally 320–442 µm wide. Spermatozeugmata (Fig. 3H, sz) 10–25 in each ampulla, about 400–860 µm long.

Known only from its type locality, Yunnan Province, China; freshwater lake, 70–110 m depth, water temperature less than 15 °C, fine clay.