Glyphidrilus chiensis Chanabun & Panha, 2013

Chanabun, Ratmanee, Sutcharit, Chirasak, Tongkerd, Piyoros & Panha, Somsak, 2013, The semi-aquatic freshwater earthworms of the genus Glyphidrilus Horst, 1889 from Thailand (Oligochaeta, Almidae) with re-descriptions of several species, ZooKeys 265, pp. 1-76 : 39-42

30. Glyphidrilus chiensis Chanabun & Panha sp. n. Figs 25 26 37 Table 1

Type material.

Holotype: CUMZ 3234 ( Fig. 26 ), in loamy sand in a rice field at Ban Thatoom, Mueang, Mahasarakham, Thailand, 16°10'47.9"N, 103°26'59.6"E, 159 m amsl, 31 March 16°10'47.9"N, 103°26'59.6"E adults (NHM), all same collection data as holotype.

Other material examined.

5 adults and 1 juvenile (CUMZ 3236), in the rice field near Nangrin waterfall, Nonsaard, Udonthani, Thailand, 17°03'23.0"N, 102°45'31.6"E, 230 m amsl, 16 February 2011. 30 adults and 5 juveniles (CUMZ 3237), Phusadokbua National Park, Dontan, Mukdahan, Thailand, 16°13'58.6"N, 104°46'44.8"E, 188 m amsl, 18 February 2011. 18 adults and 32 juveniles (CUMZ 3238), Tantip waterfall, Khaoko National Park, Khaoko, Phetchabun, Thailand, 16°39'19.3"N, 101°07'38.3"E, 250 m amsl, 27 May 2010. 25 adults and 32 juveniles (CUMZ 3281), Khon Kaen University, Mueang, Khon Kaen, Thailand, 16°27'13.9"N, 102°48'55.3"E, 167.7 m amsl, 2 May 2012.

Etymology.

The specific epithet " chiensis " is from the "Chi River" because the new species was collected from the Chi River basin.

Diagnosis.

Distinct Glyphidrilus chiensis sp. n. characters are the expanded wi tissues in 23, 24, 25, 26-29, 30, 31, 32, with clitellum in 17, 18-33, 34, 35, 36, 37, 38; gm: median paired or asymmetrical on aa in 11, 12, 13, 14 and 30, 32, 33, 34, 35, 36, lateral paired or asymmetrical on bc in 15, 16, 17, 18, 19-20, 21, 22, 23, 24, and 30, 31, 33; he in 7-11; sv in 9-11; ov in 13-14; sc sessile, elongated oval or globular in 12/13-18/19, one to fifteen pairs on each side per segment ( Table 1 ).

Description of Holotype.

Dimensions: body length 180 mm, 14.0 mm in segment 8, 14.0 mm before the clitellar wi in segment 24, 15.0 mm after wi in segment 31 in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 386 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 25-30, 4.4 mm in height, and about 0.6 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in 18-37. Four pairs of setae per segment from 2, setal formula aa:ab:bc:cd:dd = 3.0:1.0:1.6:1.0:4.0 in segment 8 and 2.6:0.7:1.9:0.7:2.8 in postclitellar segments. Female pores, male pores and spermathecal pores not visible. Gm: median paired on aa in 12-13, lateral paired or asymmetrical on bc in 15-24 and 31.

Septa 4/5-7/8 thicker, 8/9-11/12 thick and 12/13 to the last segment thin. Gi small globular within 8. Intestine enlarged from 15. Dorsal blood vessel anterior to 7. He in 7-11. No distinguishable np in first thirteen segments. Sv in 9-12, with pair in segment 12 larger than the others. Ov in 13-14. Prostate and accessory glands absent. Sc in 12/13-18/19, one to fifteen on each side per segment.

Variation.

Body length of adult paratypes (44) and non-types (78) range from 61-193 mm (128.1 ± 93.3), with 122-386 segments. Wi in 23, 24, 25, 26-29, 30, 31, 32, with clitellum in 17, 18-33, 34, 35, 36, 37, 38; gm: median paired on aa in 11, 12, 13, 14 and 30, 32, 33, 34, 35, 36, lateral paired or asymmetrical on bc in 15, 16, 17, 18, 19-20, 21, 22, 23, 24, and 30, 31, 33.

Distribution.

This new species was found on the canal connected to a waterfall in loamy sand topsoil (87.0% sand, 8.7% silt, 4.3% clay, pH 7.5-6.9), and the soil surface was covered with the worm casts. The species was found in several locations within the Chi River drainage area, in north part of Northeast and Central Thailand, and also seems likely to be found in nearby areas of the Chi River watershed.

Remarks.

Glyphidrilus chiensis sp. n. is similar to Glyphidrilus annandalei from India in the locations of wi but Glyphidrilus annandalei has slightly longer wi in 25, 26, 27- ½32, 32, ½33, 33, 35, 36, longer clitellum beginning in 13-18 and extending to 35-41, and sc in 13/14-16/17. The new species is similar to Glyphidrilus birmanicus in the locations of wi however, Glyphidrilus birmanicus has a longer clitellum in 12, 13-43, 44, and sc in 13/14-17/18.Differs from Glyphidrilus vangviengensis by the last has a shorter clitellum in 19, 20-35, 36, 37, 38, and lacks sc. Differs from Glyphidrilus yunnanensis by Glyphidrilus yunnanensis has a bit longer wi in 22-32, with a clitellum in 18-38, and lacks sc.

The new species differs from Glyphidrilus vangthongensis sp. n. which has wi in 24, 25, 26-31, 32, longer clitellum in 12, 13, 14, 15, 16-40, 41, 42, np from segment 12, gi in 7-8, and sp in 12/13-18/19. It differs from Glyphidrilus quadratus sp. n. by Glyphidrilus quadratus sp. n. having a smaller body size, wi in 23, 24-28, 29, 30, 31, the clitellum in 15, 16, 17, 18-31, 32, 33, 34, 35, 36, and two to fourteen of sp on each side per segment in 12/13-17/18. Glyphidrilus chiensis sp. n. differs from Glyphidrilus huailuangensis sp. n. by Glyphidrilus huailuangensis sp. n. has a smaller body size, with a bit shorter wi in 25, 26-30, 31, longer clitellum in 12, 13, 16-32, 33, and lacks sp ( Table 1 ).

Figures

Figure 25. Photographs showing the A type locality of Glyphidrilus chiensis sp. n. in the paddy field at Ban Thatoom, Mueang, Mahasarakham, B Glyphidrilus chiensis sp. n. casts and C coloration of newly collected paratype CUMZ 3235 just after the first preservation step in 30 % (v / v) ethanol.

Figure 26. Morphology of the holotype (CUMZ 3234) of Glyphidrilus chiensis sp. n., showing the A external ventral and B internal dorsal views.

Figure 37. Distribution map of the new Glyphidrilus species from Thailand. Open triangle: Glyphidrilus borealis sp. n., Filled triangle: Glyphidrilus vangthongensis sp. n., Filled star: Glyphidrilus chaophraya sp. n., Open square: Glyphidrilus chiensis sp. n., Filled square: Glyphidrilus quadratus sp. n., Open circle: Glyphidrilus huailuangensis sp. n.