Metaphire mangophiloides Nguyen & Le, 2015

Nguyen, Tung. T., Trinh, Binh K. T., Le, Nhan V. & Nguyen, Anh D., 2015, On the polythecate earthworms of the genus Metaphire (Oligochaeta: Megascolecidae) from Vietnam, with descriptions of three new species, Raffles Bulletin of Zoology 63, pp. 461-470 : 467-469

Metaphire mangophiloides Nguyen & Le , new species

( Fig. 3 , Table 3)

Examined material. Holotype: 1C (CTU.EW082–h01) Acacia plantation, Thien Tam community, Vinh Cuu District, Dong Nai Province, Vietnam (11 o 15’54.7” N; 107 o 03’52.7” E), 13 September 2012, coll. Duong Chi Trong. Paratype: 1C (CTU.EW082–p01) same data as for holotype.

Diagnosis. Worm medium-size, length 70–74 mm, diameter 5.25–5.31 mm. Number of setae higher in pre-clitellar than post-clitellar region; setae distance aa = 1.2 ab, zz = 1.3 yz. First dorsal pore in 12/13. Multiple spermathecal pores lateroventral in intersegment 5/6. No genital markings in both spermathecal and male regions. Holandric. Intestinal caeca manicate. Septa 8/9/10 absent.

Etymology. Named to emphasise its similarity with the species Metaphire mangophila ( Nguyen, 2011) .

Description. External characters: Body cylindrical, medium size; length 70–74 mm, diameter 5.25–5.31 mm, segments 71–78, weight 0.94–1.28 g. Body greyish brown dorsally and paler ventrally. Number of setae higher in pre-clitellar than post-clitellar region, 68–69 in v, 62–70 in viii, 60–63 in xxv, 56–62 in xxx, 17–20 between male porophores in xviii; setae distance aa = 1.2 ab, zz = 1.3 yz. Prostomium 1/3 epilobous. First dorsal pore in 12/13. Clitellum annular, xiv-xvi, smooth, without setae and dorsal pores. Female pore single, mid-ventral in xiv.

Spermathecal pores tiny, multiple, lateroventral in intersegments 5/6.

Male pores deeply located inside copulatory pouches in xviii; ventral distance between male porophores about 0.3× body circumference. Copulatory pouches having small, O-shaped openings. No genital markings in both spermathecal and male regions.

Internal characters: Septa 5/6/7/8 thickened, 8/9/10 absent. Oesophageal gizzard within viii–x. Intestinal origin at xv; caeca manicate, within xxvii–xxv. Last hearts in xiii. Pharyngeal micronephridia in 5/6/7. Lymph glands absent. Typhlosole simple, lamelliform.

Fifteen spermathecae in intrasegmental 5/6: 6–8 on the left side and 7–9 on the right side. Ampulla opalescent, subcylindrical, but slightly enlarged distally; duct extremely short, about 1/10 of ampulla length. Diverticula waved and short, about 1/3 ampulla, attached directly to ampulla duct. Accessory glands absent in spermathecal region.

Holandric. Testis sacs not separated. Seminal vesicles well developed within xi–xii, opalescent. Oviduct on septum 12/13 ventrally; a pair of small ovaries in xiii. Prostate glands large, racemose, paired in xvii–xx; prostatic ducts U-shaped. Accessory glands absent.

Habitat and ecology. The new species was found in Acacia tree plantation in Thien Tam commune, Vinh Cuu District, Dong Nai Province. All specimens were collected from soil surface, just under leaf litter at the end of the rainy season.

Remarks. This new species is fairly similar to M. mangophila ( Nguyen, 2011) and M. bitheca ( Kobayashi, 1936) in the following characters: genital makings absent in both spermathecal and male regions, intestinal caeca manicate. However, M. mangophiloides has multiple spermathecal pores in intersegment 5/6, pharyngeal micronephridia not water-drop shaped, ampulla duct extremely short (1/10 ampulla length) whereas M. mangophila ( Nguyen, 2011) has two pairs of spermathecal pores in 5/6/7, two spermathecae in each thecal segment, pharyngeal micronephridia water-drop shaped, ampulla duct relatively long (=1/3 ampulla length). M. bitheca is distinguished from new species by two grouped pairs of spermathecal pores on anterior vi and vii with each group consisting of 2+2 pores, large, oval, disc-shaped male porophores, and short, cylindrical spermathecal diverticula ( Kobayashi, 1936).

Figures

Fig. 3. Metaphire magnophiloides, new species, holotype. A, male pore region (mp = male pore); B, spermathecal region; C, spermathecae, right side (am = ampulla; dv = diverticula); D, prostate gland; E, intestinal caeca. Scale bars = 1 mm.