Glyphidrilus vangthongensis 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 : 33-36

28. Glyphidrilus vangthongensis Chanabun & Panha sp. n. Figs 21 22 37 Table 1

Type material.

Holotype: CUMZ 3229 ( Fig. 22 ). The river banks of Sakulnothayan waterfall, Vangthong, Phitsanulok, Thailand, 16°50'17.8"N, 100°31'55.2"E, 84 m amsl, 29 May 2010. Paratypes: 10 adults (CUMZ 3230), 3 adults (ZMH 14565), and 3 adults (NHM), same collection data as for holotype.

Other material examined.

10 adults (CUMZ 3231), Wanathara Resort, Vangthong, Phitsanulok, Thailand, 16°52'22.1"N, 100°38'17.5"E, 100 m amsl, 27 May 2010. 15 adults (CUMZ 3232), Chadthakan waterfall, Chadthakan, Phitsanulok, Thailand, 17°17'59.6"N, 100°40'46.0"E, 200 m amsl, 28 May 2010.

Etymology.

The species is named after Vangthong, Phitsanulok, its type locality. This is the first time this genus has been recorded from this locality.

Diagnosis.

The unique characters of Glyphidrilus vangthongensis sp. n. are clitellar wi in 24, 25, 26-31, 32, with clitellum in 12, 13, 14, 15, 16-40, 41, 42; gm: median paired on aa in 12, 13, 14 and 30, 32, 33, 34, 35, 36, lateral paired or asymmetrical on bc in 13, 14-24, 25, 26 and 31, 32, 33; sv in 9-12; he in 7-11; intestinal origin in 14; ov in 13; sc in 12/13-18/19 ( Table 1 ).

Description of Holotype.

Dimensions: body length 116 mm, diameter 7.5 mm in segment 8 and 8.0 mm before the clitellar wi in segment 24, 8.2 mm after wi in segment 32 in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 251 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 25-31, 3.1 mm in height, and about 0.4 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in 12-40. Four pairs of setae per segment from 2, setal formula aa:ab:bc:cd:dd = 2.0:0.5:1.8:2.0:2.8 in segment 8 and 1.5:0.4:1.6:0.6:2.1 in postclitellar segments. Female pores, male pores and spermathecal pores not visible. Gm laterally paired or asymmetrical on bc in 15-17, 19, 24, and 32, and median paired on aa in 12-13 and 32-33.

Septa 5/6-7/8 thicker, 8/9-10/11 thick and 11/12 to the last segment thin. Gi small globular within 7-8. Intestine enlarged from 14. Dorsal blood vessel anterior to 7. He in 7-11. No distinguishable np in first eleven segments. Sv in 9-12, with the pairs in segments 9 and 11 larger than the others. Ov in 13. Prostate and accessory glands absent. Sc in 12/13-18/19, two to thirteen on each side per segment.

Variation.

Body lengths of adult paratypes (16) and non-types (25) ranged from 62-195 mm (118.0 ± 94.0), with 150-358 segments. Wi attached on ventral lateral part of the clitellum in 24, 25, 26-31, 32, with clitellum in 12, 13, 14, 15, 16-40, 41, 42; gm: median paired on aa in 12, 13, 14 and 30, 32, 33, 34, 35, 36, lateral paired or asymmetrical on bc in 13, 14-24, 25, 26 and 31, 32, 33.

Distribution.

The new species is known from the type locality in the river banks of Sakulnothayan waterfall and Wanathara Resort, Vangthong, and Chadthakan waterfall, Chadthakan, Phitsanulok, Thailand. This species was found on the shore but in proximity to the river water, in loamy sand topsoil (88.2% sand, 10.2% silt, 1.6% clay, pH 7.5-7.6) and also under the water at about 10-15 cm depth. The soil surface was covered with worm casts near the river banks.

Remarks.

Glyphidrilus vangthongensis sp. n. differs from Glyphidrilus papillatus from Burma by Glyphidrilus papillatus having wi in 18-23, 24, 25, 26, with a shorter clitellum in 14-40, intestinal origin in 15, and sc in 14-17. Differs from Glyphidrilus annandalei from India by Glyphidrilus annandalei has longer size, longer wi in 25, 26, 27- ½32, 32, ½33, 33, 35, 36, a bit shorter clitellum starting in 13-18 ending 35-41, he in 8-11, np from segment 15, gi in 8-9, and sc in 13/14-16/17. Differs from Glyphidrilus birmanicus from Burma in that Glyphidrilus birmanicus has different locations of wi in 21, 22, 23-28, 29, 30, with a bit longer clitellum in 12, 13-43, 44, intestinal origin in 15, and sc in 13/14-17/18. Differs from Glyphidrilus yunnanensis from China by Glyphidrilus yunnanensis having longer wi in 22-32, shorter clitellum in 18-38, intestinal origin in 16, and lacks sc.Differs from Glyphidrilus vangviengensis from Laos by Glyphidrilus vangviengensis has a shorter clitellum in 19, 20-35, 36, 37, intestinal origin in 16, and lacks sc.

The new species is the most similar to three new Thai species: Glyphidrilus chiensis sp. n. from Mahasarakham, Glyphidrilus quadratus sp. n. from Kang Sapue, Ubon Ratchathani and Glyphidrilus huailuangensis sp. n. from Huailung waterfall, Ubon Ratchathani. However, Glyphidrilus chiensis sp. n. has a bit longer wi in 23, 24, 25, 26-29, 30, 31, 32, shorter clitellum in 17, 18-33, 34, 35, 36, 37, 38, intestine enlarged from 15. Glyphidrilus quadratus sp. n. has a bit longer wi in 23, 24-28, 29, 30, 31, shorter clitellum in 15, 16, 17, 18-31, 32, 33, 34, 35, 36, intestine enlarged from 15, and sc in 12/13-17/18. Glyphidrilus huailuangensis sp. n. has longer clitellum in 12, 13, 16-32, 33, an intestinal origin in 15, np from 13, and lacks sc ( Table 1 ).

Figures

Figure 21. Photographs showing the A type locality of Glyphidrilus vangthongensis sp. n. (arrow head) on a river bank of Sakulnothayan waterfall, Vangthong, Phitsanulok B Glyphidrilus vangthongensis sp. n. casts and C coloration of newly collected paratype CUMZ 3230 just after the first preservation step in 30 % (v / v) ethanol.

Figure 22. Morphology of the holotype (CUMZ 3229) of Glyphidrilus vangthongensis 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.