Metaphire doiphamon Bantaowong & Panha, 2016

Nguyen, Tung T., Lam, Dang H. & Nguyen, Anh D., 2023, A revision of the Metaphire peguana species-group (Oligochaeta: Megascolecidae) from Vietnam, Zootaxa 5255 (1), pp. 113-135 : 127-129

Metaphire doiphamon Bantaowong & Panha, 2016

( Figures 9–10, Table 3)

Metaphire doiphamon Bantaowong et al. 2016: 76 , fig. 9; Nguyen et al. 2020: 5, 2021c: 105.

Pheretima sp.4 – Nguyen et al. 2012: 146; Nguyen 2013: 63, 2014: 110

Type locality. Thailand (Chiang Rai: Doi Phamon mountain range ) ( Bantaowong et al. 2016)

Type material. Chulalongkorn University Museum of Natural History (3391), Thailand .

Diagnosis. Body cylindrical, length 161–265 mm, diameter 6.2–7.6 mm, segment 99–146. Prostomium epilobous. First dorsal pore at 12/13. Three pairs of spermathecal pores in intersegments 6/7/8/9, bithecate. Male pores located inside copulatory pouches in xviii. Genital markings paired in vi–ix, and two pairs of disc-shaped ones, each with a small central opening, in intersegments 17/18 and 18/19. Septum 10/11 appeared only ventrally. Intestinal caeca simple or slightly serrated ventrally. Holandric, testis sacs separated or connected ventrally. Accessory glands coelomic, strongly covered by muscular-walled bursae in 17/18 and 18/19.

Habitat. The species was found in the depth of 15–20 cm in soils of natural forests or long-term tree plantations in the foot of mountains. They excreted their feces to create columns emerging from the soil surface ( Nguyen 2014; Nguyen et al. 2020).

Distribution. Thailand ( Bantaowong et al. 2016), Vietnam (An Giang: Cau, Nhon, Phu Cuong, and Co To mountains; Kien Giang: Phu Quoc island) ( Nguyen 2014; Nguyen et al. 2021c) ( Fig. 3).

Remarks. Metaphire doiphamon found in Vietnam was slightly different from the description of Bantaowong et al. (2016). Vietnamese specimens have genital markings with elliptical openings at the center while type specimens have pad-shaped genital markings without openings. Unfortunately, there are no molecular evidence to compare specimens from Vietnam and Thailand.

In Vietnam, Metaphire doiphamon also has two morphological forms. Individuals from the mainland ( Fig. 9) has several differences from the one on islands (Phu Quoc Island) ( Fig. 10) such as wider distance between spermathecal pores (0.40–0.50 vs. 0.27–0.35 body circumference), more setae between male pores (11–16 vs. 3–11 setae), status of testis sacs (connected vs separated), and the diverticulum ending (at the base of ampulla duct vs. attached to the middle of ampulla duct) ( Table 3). In addition, the everted copulatory pouches were also recorded in specimens collected from islands.

The genetic distance between M. doiphamon and other Metaphire species was from 15.4%±1.7% (with M. bahli (I)) to 22.3%±2.0% (with M. posthuma ) ( Table 4).