Polypheretima militium, Nguyen, Tung T., Tran, Binh T. T. & Nguyen, Anh D., 2015

Nguyen, Tung T., Tran, Binh T. T. & Nguyen, Anh D., 2015, Three new earthworm species of the genus Polypheretima Michaelsen, 1934 (Oligochaeta: Megascolecidae) from Vietnam, Zootaxa 3905 (4), pp. 593-600 : 596-597

Polypheretima militium sp. nov.

( Fig. 2 , Tables 1, 2 )

Examined material. Holotype: 1C (CTU. EW041–h01) garden (11º08' 33.4N; 107º00' 72.9E), 45 m asl, village No.2, Ma Da commune, Vinh Cuu District, Dong Nai province, 10/10/2013, coll. Duong Chi Trong. Paratypes: 4C (CTU.EW041–p01) and 2C ( HNUE –B241. CT1. Par.), same data as for holotype.

Diagnosis. Male pores located inside copulatory pouches; copulatory pores O-shaped. Genital markings absent in male region and spermathecal regions. Spermathecal pores arranged in two pairs of pores in intersegments 5/6/7; spermathecae small, about 21–40 altogether, 7–17 per segment in 5/6 and 11–23 per segment in 6/7. Ampulla oval; duct 1/3 as long as ampulla. Diverticula cylindrical, not twisted, slightly expanded distad, much longer than ampulla, attached to ampulla at base.

Etymology. " militium " = "of the soldiers". Named in memory of Vietnamese soldiers in the Vinh Cuu District during the Vietnam War.

Description. External characters: Small to medium size, slightly bigger in xvi–xxx; body length 58–97 mm, diameter 2.58–3.57 mm, weight 0.36–1.56 gr, 137–164 segments. Body uniformly light-grey. Clitellum whitishbrown. Prostomium epilobous (1/3). First dorsal pore in 12/13 or 13/14. Setae perichaetine; preclitellar setae stouter and thicker than postclitellar setae, 67–90 in viii, 36–62 in xxx, 7–11 between male porophores in xviii; setae distance aa=2ab, zz=2zy. Clitellum annular, xiv–3/4xvi, without setae and dorsal pores. Female pore single, mid-ventral in xiv. Spermathecal pores two pairs, lateroventral in intersegments 5/6/7. Male porophores highly elevated; male pores located inside copulatory pouches in xviii; copulatory pores O-shaped. Ventral distance between male porophores about 0.35x body circumference. Genital markings absent in spermathecal and male regions.

Material examined Position Left Right Total Holotype 5/6 4 3 7

6/7 7 6 13 Paratype 1 5/6 6 6 12

6/7 7 7 14 Paratype 2 5/6 6 6 12

6/ 7 10 10 20 Paratype 3 5/6 5 5 10

6/7 7 9 16 Paratype 4 5/6 8 7 15

6/ 7 11 12 23 Paratype 5 5/6 4 5 9

6/7 5 6 11 Paratype 6 5/6 8 9 17

6/ 7 10 9 19 Internal characters: Septa 4/5/6/7/8 thickened, 8/9/10 absent, 11/12/13 thinned. Oesophageal gizzard large within ix–x. Intestinal origin at xv; caeca absent. Last hearts in xiii. Pharyngeal micronephridia well-developed on septum 4/5, poorly developed on septum 5/6. Lymph glands absent. Spermathecae small, about 21–40 altogether, 7–17 per segment in 5/6 and 11–23 per segment in 6/7. The number of spermathecae variable in specimens ( Table 1). Ampulla oval; duct about 1/3 as long as ampulla. Diverticula cylindrical, not twisted, slightly expanded distad, much longer than ampulla, attached to ampulla at base. Typhlosole simple, lamelliform. No accessory glands. Holandric. Testis sacs separated. Seminal vesicles well developed in xi–xii. Oviduct on septum 12/13 ventrally. Ovaries absent. Prostate glands racemose, paired in xviii, two main branches extending from xvii–xix; prostatic ducts getting bigger distally, ending at xviii. No accessory glands.

Remarks. Polypheretima militium sp. nov. belongs to the Po. polytheca species-group Easton, 1979 characterized by multiple spermathecae per pore, but differs from other members in having two pairs of pores in intersegments 5/6/7, about 21–40 small spermathecae altogether (7–17 per segment in 5/6 and 11–23 per segment in 6/7), and copulatory pouches. It is rather close to P. colonensis ( Thai, 1996) in the following characters: body size, setae distance (aa=2ab, zz=2zy), spermathecal pores paired in 5/6/7, no genital markings in spermathecal and male regions, septa 8/9/10 absent, last hearts in xiii. However, Po. colonensis differs from the new species in being metandric and bithecal, first dorsal pore in 11/12, and intestinal origin at xvii. The species is also similar to Po. cattienensis sp. nov. (see above), but distinguished by the body colour and the shape of the copulatory pouches (comp. Figs 1 A, 2A). Po. militium is more variable than Po. cattienensis regarding the location of the first dorsal pore (in 12/13 or 13/14) and the number of spermathecae per porus and per segment.

Locality and habitat. Vinh Cuu Natural Reserve is located in Dong Nai province, about 100 km north-east from Ho Chi Minh city. It is considered as the best-conserved area with high biodiversity values including animals, plants and habitats. The species was found a depths of 5–10 cm under the soil surface in a garden in which longterm trees were planted. Material was collected in October during dry season in southern Vietnam.

Figures

FIGURE 1. Polypheretima cattienensis sp. nov., paratype. A-B. Male pore region, ventral view (A), lateral view (B) (mp = male pore). C. Spermathecal region, lateral view (sp = spermathecal pore). D. Spermathecae in left pore in 5 / 6 (amp = ampulla, dv = diverticula). E. Prostate gland. F. Copulatory pouch, transverse body section. Scales = 1 mm.

FIGURE 2. Polypheretima militium sp. nov., paratype. A-B. Male pore region, ventral view (A), lateral view (B) (mp = male pore). C. Spermathecal region, lateral view (sp = spermathecal pore). D. Spermathecae in left pore in 5 / 6 (amp = ampulla, dv = diverticula). E. Prostate gland. F. Copulatory pouch, transverse body section. Scales = 1 mm.