Glyphidrilus quadratus Chanabun & Panha 2013

Dimensions: body length 71 mm, diameter 10.0 mm in segment 8, 11.0 mm before clitellar wi in segment 23, 11.0 mm after wi in segment 30 within the clitellum; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 274 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 24–29, 3.2 mm in height, and about 0.3 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in 15–33. Four pairs of setae per segment from 2, setal formula aa:ab:bc:cd:dd = 1.1:0.5:1.1:0.4:1.8 in segment 8 and 1.2:0.4:1.1:0.6:2.0 in postclitellar segments. Female pores, male pores and spermathecal pores not visible. Gm: median paired on aa in 13–14, lateral paired on bc in 15–23. Septa 4/5–8/9 thicker, 9/10–12/13 thick and 13/14 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 thirteen segments. Sv in 9–12. Ov in 13–14. Testis in 10–11. Prostate and accessory glands absent. Sc in 12/13–17/18, about 0.1–0.3 mm in diameter, one to fourteen on each side per segment.

The new species was found on a canal connected to a waterfall in sandy loam topsoil (79.4% sand, 14.0% silt and 6.5% clay, pH 6.7–7.3). The soil surface was covered with the worm casts. This species was found in several locations within the Mun River drainage area, in the south part of Northeast, Central and East Thailand and it also seems likely that it will be found in nearby areas of the Mun River watershed near Cambodia. This is a large distribution range, from 101o to 105 o E and 12 o to 15 o N.