Metaphire nhuongi Nguyen 2016

Metaphire nhuongi Nguyen, 2016

(Figure 13, Table 3)

Metaphire nhuongi Nguyen 2016: 442, fig. 2; Nguyen et al. 2021c: 105.

Pheretima sp. 10 – Nguyen et al. 2012: 146.

Pheretima sp. 14 – Nguyen 2013: 85, 2014: 112.

Type locality. Vietnam (An Giang: Co To mountain) (Nguyen 2016)

Type material. Laboratory of Zoology, Department of Biology, Can Tho University (EW.024.h01, EW.024. p02, EW.024.p03), Vietnam.

Diagnosis. Body cylindrical, large-medium size, length 213–339 mm, diameter 8.9–9.5 mm, segments 120–148. Prostomium epilobous. First dorsal pore at 12/13. Four pairs of spermathecal pores in ventrolateral intersegments 5/6/7/8/9, bithecate. Two pairs of ellipsoid genital markings in 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 present only 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 found in the depth of 15–20 cm in soils of natural forests or in perennial mango gardens in a mountain foot. They excreted their feces to create columns emerging from the soil surface (Nguyen 2016).

Distribution. Only recorded in Vietnam (An Giang: Co To, Phu Cuong, and Ta Pa mountains) (Fig. 3).

Remarks. There were no significant morphological differences between individual found.

The K2P intraspecific genetic distance was 1.3%±0.3%. The genetic distance between M. nhuongi and other Metaphire species was from 17.6%±1.8% (with M. dorsomultitheca) to 22.9%±2.1% (with M. grandiverticulata) (Table 4).

Key to species of Metaphire peguana species-group

1. – Bithecate, one pair of spermathecae per segment.......................................................... 2 – Polythecate, numerous spermathecae per segment......................................................... 6

2. – Four pairs of spermathecal pores in 5/6/7/8/9...................................................... M. nhuongi – Three pairs of spermathecal pores in 6/7/8/9............................................................... 3

3. – Genital markings paired in vi–ix............................................................. M. doiphamon – Genital markings absent in the spermathecal region......................................................... 4

4. – Spermathecal pores located ventrally. Ventral distance between spermathecal pores 0.15–0.29 body circumference. M. bahli – Spermathecal located more laterally. Ventral distance between spermathecal pores 0.33–0.50 body circumference....... 5

5. – The openings of genital markings small, slit-shaped or ellipsoid-shaped, in post-setal and pre-setal positions in xvii and xix, respectively....................................................................... M. peguana laisonensis – The openings of genital markings disc-shaped, in 17/18 and 18/19, expanding to reach two setal rings. M. peguana peguana

6. – Spermathecal pores located in ventral intersegments 6/7/8/9. Genital markings paired in 17/18 and 18/ 19 M. kiengiangensis – Spermathecal pores located in dorsal intersegments 7/8/9. Genital markings opening on the walls of the copulatory pouches M. dorsomultitheca