Glyphidrilus vesper Chanabun & Panha 2013

Dimensions: body length 100 mm, diameter 2.8 mm in segment 8, 2.9 mm before clitellar wi in segment 17, 2.8 mm behind wi in segment 25 in intraclitellar region. Body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 194 segments. Body colour pale brown with variations from red to pink at adjacent tissues of wi portion in different individuals of newly collected specimens after placement in 30% ethanol for narcotization. Dorsal surface considerably broader than the ventral at posterior end. Clitellar wi on ventro-lateral part of clitellum in 18–24, 5.4 mm in height, and about 0.6 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in 17–31. Four pairs of setae per segment from 2, setal formula aa:ab:bc:cd:dd = 1.0:0.5:1.0:0.7:1.1 in segment 8 and 0.9:0.6:1.2:0.6:1.1 in postclitellar segments. Female pores, male pores, and spermathecal pores are not visible. Gm: median unpaired on aa in 12–13, 25, lateral paired or asymmetrical on bc in 17. Septa 5/6–9/10 thick, 10/11 to the last segment thin. Gi small globular within 7–8. Intestine enlarged from 15. Dorsal blood vessel aborted anterior to 7. He in 7–11. No distinguishable np in first twelve segments. Sv in 9–12. Ov in 13–14. Testis in 10–11. Prostate and accessory glands absent. Sc sessile, elongated oval or globular in 13/14–16/17, 0.2–0.3 mm in diameter, three to six on each side per segment.

The new species was found on a waterfall shore in silt topsoil (90% silt and 10% clay, pH 5.9–6.6), covered with worm casts at several locations of West Thailand nearby Burma at Tak and Kanchanaburi.