A revision of the Metaphire peguana species-group (Oligochaeta: Megascolecidae) from Vietnam Author Nguyen, Tung T. Department of Biology, School of Education, Can Tho University, Vietnam. Author Lam, Dang H. 0000-0002-1236-1087 Department of Biology, School of Education, Can Tho University, Vietnam. & lamhaidangct @ gmail. com; https: // orcid. org / 0000 - 0002 - 1236 - 1087 lamhaidangct@gmail.com Author Nguyen, Anh D. 0000-0001-9273-0040 Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18, Hoangquocviet Rd., Caugiay, Hanoi. & ducanh 410 @ yahoo. com; https: // orcid. org / 0000 - 0001 - 9273 - 0040 & Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18, Hoangquocviet Rd., Caugiay, Hanoi. ducanh410@yahoo.com text Zootaxa 2023 2023-03-15 5255 1 113 135 http://dx.doi.org/10.11646/zootaxa.5255.1.15 journal article 10.11646/zootaxa.5255.1.15 1175-5326 7744555 3F27E81A-87C7-48CD-8DF7-6FFDA0CD4907 Metaphire peguana peguana ( Rosa, 1890 ) ( Figure 4 , Table 3 ) Perichaeta peguana Rosa 1890: 113 , figs. 6–8; Beddard 1895: 403 . Amynthas ( Pheretima ) peguanus – Michaelsen 1899: 7 . Pheretima peguana – Michaelsen 1900: 292 ; Gates 1939: 102 , 1972: 207 ; Omodeo 1956: 325 ; Thai 1983: 124 ; Thai 1987: 7 , 2000: 309 ; Thai & Do 1989: 77 ; Nguyen & Tran 2008: 185 ; Thai et al. 2004: 759 ; Huynh 2005: 88 ; Nguyen et al. 2010: 114, 2011: 1025; 2012: 146; Nguyen & Nguyen 2010: 123; Nguyen 2014: 109 . Amyntas peguanus Beddard 1900: 628 . Pheretima peguanna (sic!) – Huynh & Nguyen 2004: 116 . Metaphire peguana – Sims & Easton 1972: 239 ; Easton 1981: 58 ; Blakemore 2002: 207 , 2008: 78 , 2016: 7; Shen & Yeo 2005: 14 ; Sarkar et al. 2012: 178; Nguyen et al. 2016: 63 ; 2020: 8 . Metaphire peguana peguana – Nguyen et al. 2017a: 98 , 2021a: 17 , 2021c: 105 ; Lam et al. 2021 : 17701 . Type locality. Myanmar ( Rangoon ) ( Rosa 1890 ) Type material. Natural History Museum Giacomo Doria (44037), Italy . FIGURE 4. Metaphire peguana peguana ( Rosa, 1890 ) . A. Ventral view of the male pore region, B. Right spermathecae, C. Right prostatic gland, D. Caecum, E. Ventral view of spermathecal region, F. Transverse body section of the male copulatory pouch, G. Transverse body section of accessory gland. Scale bar=1 mm. TABLE 3: A morphological comparison between Metaphire peguana -group members and M. pacseana
No. Characters M. bahli M. doiphamon M. dorsomultitheca M. kiengiangensis M. nhuongi M. peguana peguana M. peguana laisonensis M. pacseana
1. Length (mm) 76–170 101–236 63–107 115–286 206–266 81–157 53–114 273–328
2. Diameter average (mm) 3,02–5.43 4.92–8.44 2.97–4.53 4.57–8.36 8.59–9.08 3.39–6.27 2.44 –4.46 6,14–11,41
3. Segments 57–135 78–115 75–122 66–152 118–145 60–157 62–118 128–163
4. First dorsal pore 12/13 12/13 12/13 12/13 12/13 12/13 or 13/14 12/13 12/13
5. Setae between male pores 0–10 3–16 3–6 10–19 12–15 2–13 4–13 17–50
6. Spermathecal pore 3 pairs, 6/7/8/9 3 pairs, 6/7/8/9 Numerous, 7/8/9 Numerous, 6/7/8/9 4 pairs, 5/6/7/8/9 3 pairs, 6/7/8/9 3 pairs, 6/7/8/9 3 pairs, 6/7/8/9
7. GM in spermathecal region Absent 4 pairs in vi–ix Absent Absent Absent Absent Absent Absent
8. GM in male region 2 pairs, 17/18/19 2 pairs, 17/18/19 Absent 2 pairs, 17/18/19 2 pairs, 17/18/19 2 pairs, 17/18/19 2 pairs, xvii, xix 2 pairs, 17/18/19
9. Male GM position Inline with male pores Inline with male pores Invisible from outside Inline with male pores Inline with male pores Inline with male pores Inline with male pores Near mid–ventral line
10. Male GM shape Invaginated, slit like openings Not invaginated, disc shaped Invisible from outside Invaginated Not invaginated, disc shaped Not invaginated, disc shaped Invaginated, slit like or ellipse- shaped openings Not invaginated, elipsoidal
11. Distance between male pores/body circumference 0.11–0.23 0.21–0.31 0.18–0.25 0.20–0.35 0.27–0.32 0.22–0.38 0.21–0.33 0.22–0.40
12. State of septum 10/11 Only appear ventrally Only appear ventrally Only appear ventrally Only appear ventrally Only appear ventrally Only appear ventrally Only appear ventrally Fully developed
13. Spermatheca Bithecate Bithecate Polythecate Polythecate Bithecate Bithecate Bithecate Bithecate
14. Caeca Simple Simple or serrate Simple Simple Simple Simple Simple Manicate
15. Testis sacs Separated Separated or connected Separated Separated Separated Separated Separated Connected
16. Prostatic gland xvi – xxii xvi–xx xvii–xx xvii–xx xvii–xix xvi–xxi xvii–xx xvi–xxiii
17. Base of diverticulum Ampulla base Ampulla base or on ampulla duct Ampulla base Ampulla base Ampulla base Ampulla base On ampulla duct Ampulla base
18. Accessory gland 2 pairs, 17/18/19 2 pairs, 17/18/19 2 pairs, 17/18/19 2 pairs, 17/18/19 2 pairs, 17/18/19 2 pairs, 17/18/19 2 pairs, xvii, xix 2 pairs, 17/18/19
19. Accessory gland structure Muscular–walled cover Muscular–walled cover Muscular–walled cover Muscular–walled cover Muscular–walled cover Muscular–walled cover Muscular–walled cover Massed
Diagnosis. Body cylindrical, length 81–143 mm , diameter 3.7–6.3 mm , segments 60–157. Prostomium epilobous. First dorsal pore at 12/13 or 13/14. Three pairs of spermathecal pores in ventrolateral intersegments 6/7/8/9, bithecate. Two pairs of disc–shaped genital markings on intersegments 17/18 and 18/19, each with a small opening at the center. Male pores located inside copulatory pouches in xviii. Septum 10/11 only present ventrally. Intestinal caeca simple. Holandric, testis sacs separated. Accessory glands coelomic, strongly covered by muscularwalled bursae in 17/18 and 18/19. Habitat. The species is found in leaf litter in various types of habitats in Southern Vietnam . Distribution. French Guiana ( Csuzdi & Pavlíček 2010 ), India , Thailand ( Blakemore et al. 2006 ; Prasankok et al. 2013 ), Myanmar , Malaysia , Indonesia , Japan ( Gates 1972 ; Ishizuka 1999 ; Ng et al. 2017 ), Singapore ( Shen & Yeo 2005 ), Cambodia , Laos (Thai & Samphon 1989), Bangladesh (Sarkar et al. 2012), Australia ( Easton 1982 ), and commonly found in Vietnam ( Nguyen et al. 2016 , 2021a , 2021c ; Lam et al. 2021 ) ( Fig. 3 ). Remarks. Metaphire peguana peguana is the typical form and the one found outside of Southeast Asia along with M. bahli . Although this subspecies has a relatively stable morphology with genital markings paired in 17/18 and 18/19, there was still a slight difference throughout populations in Vietnam . Vietnamese specimens have a greater ventral distance between spermathecal pores than other populations (0.33–0.50 vs. 0.28–0.29 body circumference) ( Rosa 1890 ; Gates 1972 ; Bantaowong et al. 2011 ). In addition, the genetic distance among Vietnamese specimens was from 3% ( Table 4 ) while that from Thailand and Malaysia is about 4.8% ( Prasankok et al. 2013 ; Jeratthitikul et al. 2017 ; Ng et al. 2017 ). The genetic distance between M. peguana peguana and other Metaphire species from 15.1%±1.6% (with M. bahli ( type II)) to 23.5%±2.1% (with M. grandiverticulata ) ( Table 4 ).