Glyphidrilus chiangraiensis 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 : 6-8

Glyphidrilus chiangraiensis Chanabun & Panha sp. n. Figs 1, 6, 7, Table 1

Type material.

Holotype: One adult (CUMZ 3407) in the river banks of Mekong River at Wat Hatkai, Chiangkhong, Chiangrai, north Thailand (20°15'8.5"N, 100°24'46.8"E), 384 meters elevation on 14 March 2014. Paratypes: 9 adults (CUMZ 3408), 2 adults (ZMH 14581), 2 adults (NHMUK), and 2 adults (ZRC), all specimens collected only from the type locality.

Other material examined.

43 adults (CUMZ 3409), in the river banks of Mekong River at Mueang, Buengkan, northeast Thailand (18°22'2.4"N, 103°38'58.0"E), 144 meters elevation on 6 December 2013. 33 adults (CUMZ 3410), in the river banks of Mekong River at Kang Kudku, Chiangkhan, Loei, northeast Thailand (17°54'24.5"N, 101°42'7.5"E), 195 meters elevation on 8 December 2013. 25 adults (CUMZ 3411), in the river banks of Mekong River at Wat Srisomsanook, Chiangkhan, Loei, northeast Thailand (17°59'25.4"N, 101°44'51.3"E), 212 meters elevation on 7 December 2013. 11 adults (CUMZ 3412), in the river banks of Mekong River at Wat Hadphatum, Srichiangmai, Nongkhai, northeast Thailand (17°57'32.2"N, 102°35'26.8"E), 174 meters elevation on 7 December 2013. 38 adults (CUMZ 3413), in the river banks of Mekong River at Wat Jomnang, Phonphisai, Nongkhai, northeast Thailand (18°01'53.6"N, 103°4'47.4"E), 165 meters elevation on 6 December 2013. 30 adults (CUMZ 3414), in the river banks of Mekong River at Wat Prayanakmai, Wiangkaen, Chiangrai, north Thailand (20°11'45.2"N, 100°27'32.0"E), 359 meters elevation on 15 March 2014. 19 adults (CUMZ 3415), in the river banks of Mekong River at Wat Bansaw, Chiangsan, Chiangrai, north Thailand (20°15'19.4"N, 100°10'44.9"E), 385 meters elevation on 14 March 2014. 26 adults (CUMZ 3416), in river banks of Mekong River at Ban Rimkhong, Pakchom, Loei, northeast Thailand (18°12'48.9"N, 102°04'52.2"E), 181 meters elevation on 8 December 2013. 3 adults (CUMZ 3417), in river banks of Mekong River, Mueng Paksay, Chaiyaburi, Laos (18°12'40.0"N, 101°24'28.1"E), 214 meters elevation on 15 April 2014. 15 adults (CUMZ 3418) in river banks of Mekong River, Bandon, Luangprabang, Laos (19°55'27.6"N, 102°10'49.7"E), 304 meters elevation on 14 April 2014. 24 adults (CUMZ 3419) in river banks of Mekong River, between Sanakham to Vientiane, Laos (17°57'39.7"N, 101°43'53.8"E), 224 meters elevation on 15 April 2014.

Diagnosis.

Glyphidrilus chiangraiensis sp. n. has clitellar wings on the lateral side of the body in XXIII, XXIV–XXVI, ½ XXVII, XXVII, ½ XXVIII, XXVIII. Clitellum in XVII, XVIII, XIX, XX, XXI–XXXVI, XXXVII, XXXVIII, XXXIX. Female pores, male pores and spermathecal pores not visible. Genital markings: paired or asymmetrical on aa in XII–XIV, XV, XVI, paired or asymmetrical on bc in XXI, XXII, XXIII, XXIV and XXVII, XXVIII, XXIX–XXXV. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XVI. Ovaries in XIII–XIV. Spermathecae between 15/16-20/21.

Description of holotype.

Dimensions: body length 158 mm, diameter 3.0 mm in segment VIII, 4.0 mm before the clitellar wing in segment XXIII, 4.0 mm after wing in segment XXIX in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 282 segments. Body color pale brown with variations from red to pink at adjacent tissues of wing portion in different individuals of newly collected specimens. Clitellar wing on ventro-lateral part of clitellum in XXIV–XXVII, ½ XXVIII, 3.7 mm and 4.0 mm in height, and 0.5 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XVII–XXXVIII. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd=2.0:1.0:2.0:1.0:2.0 in segment VIII and 2.0:1.0:2.0:1.0:2.5 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: paired on aa in XIV, laterally paired or asymmetrical on bc in XXIII and XXIX–XXXV.

Septa 5/6-8/9 thicker than between other segments, 9/10-13/14 thick and 14/15 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, small elongated oval or globular between 15/16-20/21, about 0.1-0.2 mm in diameter, three to twelve per segment on each side per segment.

Variations.

Body lengths of adults (n = 283) ranged from 94-340 mm (155.42 ± 54.93), with 89-394 segments. Wings in XXIII, XXXIV–XXVI, ½ XXVII, XXVII, ½ XXVIII, XXVIII, clitellum in XVII, XVIII, XIX, XX, XXI–XXXVI, XXXVII, XXXVIII, XXXIX. Genital markings: paired or asymmetrical on aa in XII–XIV, XV, XVI, paired or asymmetrical on bc in XXI, XXII, XXIII, XXIV and XXVII, XXVIII, XXIX–XXXV.

Distribution.

The new species is known from the type locality in the river banks of Mekong River at Wat Hatkai, Chiangkhong, Chiangrai, north Thailand, and was found in several locations along the Mekong River and its tributaries in the northeast and north of Thailand at Buengkan, Loei, Nongkhai, and Chiangrai and in Chaiyaburi, Luangprabang, and Sanakham to Vientiane of Laos.

Etymology.

The species was named after Chiangrai, the locality name.

Remarks.

(see Table 1) Glyphidrilus chiangraiensis sp. n. differs from G. vangviengensis Chanabun & Panha, 2011 from Song River, Vieintiane, Laos by the latter having longer wings in XXIV, XXV–XXXI, XXXII, the genital markings widely paired in bc XVIII, XIX, XX, XXI–XXIV and XXXIII, XXXIV, paired on aa in XII–XIV, XV and lacking spermathecae. It differs from G. yunnanensis Chen & Xu, 1977 reported from China by G. yunnanensis having longer wings in XXII–XXXII, clitellum in XVIII–XXXVIII, and lacking spermathecae. It differs from the species recorded as G. mekongensis Panha & Chanabun, 2012 from Mekong River, Thailand by G. mekongensis having longer wings in XXIV–½ XXXIII, XXXIII, XXXIV, ½ XXXV, and lacking spermathecae. It differs from G. chiensis Chanabun & Panha, 2013 from Chi River, Mahasarakham, northeast Thailand by G. chiensis having longer wings in XXIII, XXIV, XXV, XXVI–XXIX, XXX, XXXI, XXXII, and spermathecae between 12/13-18/19. It differs from G. quadratus Chanabun & Panha, 2013 reported from the Mun River by G. quadratus having longer wings in XXIII, XXIV–XXVIII, XXIX, XXX, XXXI, a bit longer clitellum in XV, XVI, XVII, XVIII–XXXI, XXXII, XXXIII, XXXIV, XXXV, XXXVI, and spermathecae between 12/13-17/18. It differs from G. huailuangensis Chanabun & Panha, 2013 recorded from Najahlauy National Park, Ubon Ratchathani, northeast Thailand by the latter having longer wings in XXV, XXVI–XXX, XXXI, clitellum in XII, XIII, XVI–XXXII, XXXIII, and lacks spermathecae. Glyphidrilus chiangraiensis sp. n. differs from G. namphao sp. n. by the latter having wings in XVIII–XXIV, clitellum in XVII–XXVI, XXIX, genital markings: paired on aa in XVII; paired or asymmetrical on bc in XII–XV, XXV, XXVI, and spermathecae between 13/14-16/17. It differs from G. sekongensis sp. n. by the latter having wings in XXV–XXXI, clitellum in XVI, XVII–XXXVI, XXXVII, and spermathecae between 12/13-15/16. It differs from G. champasakensis sp. n. from Mekong River at Ban Khonkhen, Champasak, Laos by the latter having longer wings in XXIII, XXIV–½ XXXII, XXXII, XXXIII, longer clitellum in XIX, XX–XLIX, L, LI, LII, and spermathecae between 14/15-19/20.