Glyphidrilus jamiesoni Jirapatrasilp, Chanabun & Panha

Jirapatrasilp, Parin, Prasankok, Pongpun, Sutcharit, Chirasak, Chanabun, Ratmanee & Panha, Somsak, 2016, Two new Cambodian semi-aquatic earthworms in the genus Glyphidrilus Horst, 1889 (Oligochaeta, Almidae), based on morphological and molecular data, Zootaxa 4189 (3), pp. 543-558 : 548

1. Glyphidrilus jamiesoni Jirapatrasilp, Chanabun & Panha , sp. n.

( Figure 2 )

Type specimens. Holotype CUMZ 3397 (adult; Fig. 2 ), paratypes CUMZ 3398 (23 adults and 57 juveniles), NHMUK (two adults), and ZMH 14585 (two adults), leg. P. Jirapatrasilp, C. Sutcharit, W. Siriwut, and R. Srisonchai, 8 Feb 2015.

Type locality. Stream banks near Praduk Temple , Banteay Srei District, Siem Riep Province, Cambodia, 13º28’46.4”N, 103º56’18.1”E, 15 m amsl. ( Fig. 1 Loc. 12, Fig. 4A ).

Other material examined. Three adults and 20 juveniles ( CUMZ 3399 ), Banteay Srei Temple , Banteay Srei District, Siem Riep Province, Cambodia, 13º35’56.1”N, 103º57’47.8”E, 15 m amsl ( Fig. 1 Loc. 13), 7 Feb 2015.

Diagnosis. Wings between segment 23, 24–31, 32, 33; clitellum in 17, 18–35, 36; genital markings paired or unpaired on aa in pre-wing 12, 13, 14, and post-wing 31, 33, paired or asymmetrical on bc in pre-wing 15, 16, 17, 18–22, 23, and post-wing 31, 32; intestine enlarged in 16; ovaries in 13–14; spermathecae sessile, elongated oval or globular in 13/14–18/19 ( Table 2 ).

Description of holotype. Body length 114 mm, diameter 3.82 mm in segment 8, 4.70 mm in front of wings in segment 22, 4.35 mm behind wings in segment 43; body cylindrical in anterior part, quadrangular in cross-section behind clitellum. 307 segments. Body color pale brown with reddish tint from the first segment to clitellar portion. At posterior end dorsal surface broader than ventral. Clitellar wings on ventro-lateral part of clitellum, left wing in 24–32, right wing in ½24–32, 4.75–5.37 mm in height, 0.6 mm wide. Prostomium zygolobous. Dorsal pores absent. Clitellum annular but not totally fused in 17–35. Four pairs of setae per segment from 2, setal formula aa: ab: bc: cd: dd = 1.59: 0.80: 1.53: 0.74: 1.86 in segment 6 and 1.79: 0.73: 1.75: 0.59: 2.19 in postclitellar segments. Female, male and spermathecal pores not visible. Genital markings unpaired on aa in 12 and 13, and paired on bc in 17–22.

Septa 5/6–7/8 thickest, 8/9–11/12 thick and 12/13 to the last segment thin. Gizzard globular within 7–8. Intestine enlarged from 16. Dorsal blood vessel anterior to 7. Hearts in 7–11. A pair of nephridia in each segment, rudimentary in 13, small in 14, and normal in 15 onwards. Seminal vesicles in 9–12. Ovaries in 13–14. Testes in 10–11. Prostate and accessory glands absent. Spermathecae sessile, elongated oval or globular in 13/14–18/19, about 0.2 mm in diameter, one to seven on each side per segment.

Variation. Body lengths of adult paratypes (27) and non-types (3) ranged from 82–114 mm (mean ± S.D. = 101.7 ± 8.8), with 165–307 segments. Wings begin in 23 or 24 and end in 31, 32, or 33; the most frequent position is 24–32. Clitellum begins in 17 or 18 and ends in 35 or 36. Most specimens have genital markings paired or unpaired on aa in pre-wing 12, some occur in 13, 14, and post-wing 31, 33. Genital markings paired or asymmetrical on bc start in pre-wing 15, 16, 17, or 18 and ends in 22, 23, and some occur in post-wing 31, 32; the most frequent position is 18–22 ( Table 2 ).

Distribution. The new species is known from the type locality, Praduk Temple, and also from Banteay Srei, Siem Riep, Cambodia.

Habitat. The species was found on stream banks and in paddy fields where the worm casts covered the surface ( Fig. 4 B). Earthworms occurred in the muddy loam topsoil at about 10–20 cm depth.

Etymology. The specific name was dedicated to Barrie G. M. Jamieson, an Australian oligochaetologist, who extensively reviewed the taxonomy and systematics of semi-aquatic earthworms, including the family Almidae .

Remarks. Glyphidrilus jamiesoni sp. n. is similar to G. vangviengensis in the wing locations, but has spermathecae in 13/14–18/19. For further comparison of Mekong Glyphidrilus species, see Table 2.

Figures

FIGURE 1. Map of sampling localities of Glyphidrilus spp. in the Mekong River Basin in Thailand, Laos and Cambodia. Locality numbers (1 – 14) correspond to those in Table 1 and 2. Numbers with an asterisk designate type localities. Loc. 1: Rice field at Ban Thatoom, Mueang, Mahasarakham, Thailand. Loc. 2: Huailuang waterfall, Najahlauy, Ubon Ratchathani, Thailand. Loc. 3: Mekong River, Khong Chiam, Ubon Ratchathani, Thailand. Loc. 4: Khut Khu Islets, Chiang Khan, Loei, Thailand. Loc. 5: Bueng Kan Mekong River pathway, Mueang, Bueng Kan, Thailand. Loc. 6: Salung Beach, Pho Sai, Ubon Ratchathani, Thailand. Loc. 7: Kang Saphue, Mun River, Phibunmangsahan, Ubon Ratchathani, Thailand. Loc. 8: Song River, Vangvieng, Vientiane, Laos. Loc. 9: Phonevichith Guesthouse, Houayxay, Bokeo, Laos. Loc. 10: Ban Arjsamart, Muang, Nakon Panom, Thailand. Loc. 11: Pakse Mekong River pathway, Pakse, Champasak, Laos. Loc. 12: Stream near Praduk Temple, Banteay Srei, Siem Riep, Cambodia. Loc. 13: Banteay Srei Temple, Banteay Srei, Siem Riep, Cambodia. Loc. 14: Tapan River, Kralanh, Siem Riep, Cambodia.

FIGURE 2. Morphology of the holotype (CUMZ 3397) of G. jamiesoni sp. n. A. External ventral view. B. Internal dorsal view after dissection; some anterior pairs of nephridia are not shown.

FIGURE 4. A. Type locality of G. jamiesoni sp. n. on the stream banks near Praduk Temple, Banteay Srei, Siem Riep. B. Same as A, casts. C. Type locality of G. kralanhensis sp. n. on the bank of Tapan River, Kralanh, Siem Riep. D. Paratype specimen of G. jamiesoni sp. n. (CUMZ 3398). E. Paratype specimen of G. kralanhensis sp. n. (CUMZ 3401). Both specimens photographed immediately after the first preservation in 30 % (v / v) ethanol.