Glyphidrilus namphao Chanabun & Panha

Chanabun, Ratmanee, Inkavilay, Khamla & Panha, Somsak, 2017, New species of semi-aquatic freshwater earthworm genus Glyphidrilus Horst, 1889 from Thailand and Laos (Oligochaeta, Almidae), ZooKeys 672, pp. 1-34 : 9-11

Glyphidrilus namphao Chanabun & Panha sp. n. Figs 1, 8, Table 1

Type material.

Holotype: One adult (CUMZ 3420) in a river banks of Phao River between Ban Lak 7 and Ban Lak 5, Kamkerd, Bolikhamxai, Laos (18°16'27.7"N, 105°2'44.0"E), 525 meters elevation on 7 December 2013. Paratypes: 2 adults and 8 juveniles (CUMZ 3421), 1 adult (ZMH 14582), all specimens collected from only the type locality.

Diagnosis.

Glyphidrilus namphao sp. n. is a small worm with the clitellar wings on the lateral side of the body in XVIII–XXIV. Clitellum in XVII–XXVI, XXIX. Female pores, male pores and spermathecal pores not visible. Genital markings: paired or asymmetrical on aa in XVII; paired or asymmetrical on bc in XII–XV and XXV, XXVI. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XVI. Ovaries in XIII–XIV. Spermathecae between 13/14-16/17.

Description of holotype.

Dimensions: body length 92 mm, diameter 3.1 mm in segment VIII, 4.2 mm before the clitellar wing in segment XVII, 4.2 mm after wing in segment XXV in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 269 segments. Body color pale brown with variations from red to pink at adjacent tissues of wing portion in different individuals of newly collected specimens. At posterior end dorsal surface considerably broader than the ventral. Clitellar wing on ventro-lateral part of clitellum in XVIII–XXIV, 3.5 mm in height, and 0.25 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XVII–XXIX. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd =1.5:0.5:1.5:0.5:2.0 in segment VIII and 1.5:0.5:1.5:0.5:2.5 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: paired on aa in XVII, laterally paired or asymmetrical on bc in XII–XV and XXV.

Septa 4/5-6/7 thicker than between other segments, 7/8-11/12 thick and 12/13 to the last segment thin. Gizzard small, globular in VIII. Intestine enlarged from XVI. Hearts, five pairs in VII–XI, first in VII and last in XI. A pair of holonephridia in each segment from segment XIII onwards. Seminal vesicles, four pairs in IX, X, XI, XII. Ovaries, two pairs in XIII and XIV. Testis free in X and XI. Prostate and accessory glands absent. Spermathecae sessile and diverticula absent, elongated oval or globular between 13/14-16/17, about 0.3-0.4 mm in diameter, two to seven on each side per segment.

Variations.

Body lengths of adult (n = 4) and juvenile paratypes (n = 8). Adults ranged from 64-122 mm (89.7 ± 20.8), with 190-320 segments. Juveniles ranged from 64-120 mm (98.3 ± 17.6), with 193-311 segments. Wings in XVIII–XXIV, clitellum in XVII–XXVI, XXIX. Genital markings: paired or asymmetrical on aa in XVII; paired or asymmetrical on bc in XII–XV and XXV, XXVI.

Distribution.

The new species was found in the river banks of Phao River which was covered with worm casts.

Etymology.

The species was named after the Phao River, the type locality.

Remarks.

Glyphidrilus namphao sp. n. is different from G. vangviengensis Chanabun & Panha, 2011 reported from Song River Veintiane, Laos in different locations of wings in XXIV, XXV–XXXI, XXXII, longer clitellum in XIX, XX–XXXV, XXXVI, XXXVII and lacking spermathecae. It differs from G. nanensis sp. n. from Nan River at Saklek, Phichit, north Thailand by G. nanensis sp. n. having wings in XXIV, XXV, XXVI -XXVII, XXVIII, XXIX, a longer clitellum in XVII, XVIII–XXXIII, XXXIV, and spermathecae between 13/14-17/18. It is different from G. sekongensis sp. n. from Ban Kiangkong, Lamarm, Sekong, Laos in the locations of wings in XXV–XXXI, a longer clitellum in XVI, XVII–XXXVI, XXXVII, the genital markings paired or asymmetrical on bc in XVI, XVII–XXIV, XXXII, and spermathecae between 12/13-15/16. Glyphidrilus namphao sp. n. differs from G. chiangraiensis sp. n. from Mekong River at Wat Hatkai, Chiangkhong, Chiangrai, north Thailand in the locations of wings in XXIII, XXIV–XXVI, ½ XXVII, XXVII, ½ XXVIII, XXVIII, a longer clitellum in XVII, XVIII, XIX, XX, XXI–XXXVI, XXXVII, XXXVIII, XXXIX, and spermathecae between 15/16-20/21 (see Table 1).