Glyphidrilus chaophraya Chanabun & Panha 2013

Dimensions: body length 116 mm, diameter 2.7 mm in segment 8, 4.4 mm before the clitellar wi in segment 23, 3.9 mm after wi in segment 33 in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 325 segments. Body colour pale brown with variations from red to pink at adjacent tissues of wi portion in different individuals of newly collected specimens. At posterior end dorsal surface considerably broader than the ventral. Clitellar wi on ventro-lateral part of clitellum in 24–32, 4.6 mm in height, and about 0.6 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in 20–43. Four pairs of setae per segment from 2, setal formula aa:ab:bc:cd:dd = 1.6:0.6:1.2:0.6:2.4 in segment 8 and 1.6:0.5:1.2:0.5:2.1 in postclitellar segments. Female pores, male pores and spermathecal pores not visible. Gm: laterally paired or asymmetrical on bc in 20–23 and median paired on aa in 13, 14 and 34. Septa 5/6–7/8 thicker, 8/9–10/11 thick and 11/12 to the last segment thin. Small globular gi within 8. Intestine enlarged from 15. Dorsal blood vessel anterior to 7. He in 7–11. No distinguishable np in first fourteen segments. Sv in 9–12, pair in segment 12 larger than the others. Ov in 13–14. Prostate and accessory glands absent. Sc in 16/17–22/23, about 0.1–0.3 mm in diameter, one to thirteen on each side per segment.

The new species is known from the type locality in the river banks of Chaophraya River, Payuhakiri, Nakhonsawan, Thailand. This species was found on the shore but in proximity to the river water, in the loamy sand topsoil (88.2% sand, 10.2% silt, 1.6% clay, pH 7.5–7.6) and also under the water at about 20–30 cm depth. The soil surface was covered with worm casts near the river banks.