Metaphire dorsobitheca (Thai & Huynh, 1992)

Nguyen, Tung T., Lam, Dang H., Trinh, Binh T. K. & Nguyen, Anh D., 2020, The megascolecid earthworms (Annelida, Oligochaeta, Megascolecidae) in the Phu Quoc island, Vietnam, with descriptions of three new species, ZooKeys 932, pp. 1-25 : 1

Metaphire dorsobitheca (Thai & Huynh, 1992) Fig. 10

Material examined.

1 mature (CTU-EW.191.h01), 9 matures (CTU-EW.191.p02), 24 matures (CTU-EW.191.03), Kien Giang Province, Phu Quoc island, industrial tree plantations (10°09'31"N, 104°00'38"E), 16 m, 5 November 2016, coll. Lam HD & Trinh TKB.

Diagnosis.

Small to medium-sized. Prostomium epilobous. First dorsal pore in 12/13. Three pairs of spermathecal pores in dorsal intersegments 6/7/8/9. Male pores located inside copulatory pouches in xviii. No genital markings. Penial setae present. Intestinal caeca simple. Holandric. Testis sacs connected in xi. Septa 8/9/10 absent.

Re-description.

Body cylindrical, small to medium-sized, length 81-118 mm, diameter 3.3-3.7 mm, segments 106-142, weight 0.5-0.8 g. Body uniformly whitish grey, clitellum darkish brown. Prostomium 1/2 epilobous. First dorsal pore in 12/13. Pre-clitellum setae stouter and sparser than post-clitellum setae; setal numbers: 44-47 in viii, 54-58 in xxx, 7-8 between two openings of copulatory pouches; setal distance aa> ab, zz ≥ zy. Clitellum within xiv-xvi, slightly flattened ventrally, without setae and dorsal pores. Female pore single, in mid-ventral xiv.

Three pairs of spermathecal pores in dorsal intersegments 6/7/8/9, located near dorsal line. Genital markings absent in the spermathecal region. Male pores located inside copulatory pouches in xviii; ventral distance between two openings of copulatory pouches about 0.3 × body circumference. No genital markings in the male region.

Septa 5/6/7/8 thick, 8/9/10/11 absent, 11/12/13 thin. Oesophageal gizzard within viii-xi. Intestinal origin at xv. Intestinal caeca simple, within xxvii-xxv. Last hearts in xiii. Typhlosole lamelliform. Lymph glands lobuled, from 17/18.

Three pairs of spermathecae in vii-ix. Ampulla clavate; ducts long. Diverticula thin, waved, shorter than ampulla, attached to the base of ampulla; seminal chamber ellipsoid. No accessory glands.

Holandric. Testis sacs in xi, connected. Seminal vesicles xi and xii well developed. Ovaries in 12/13. Ovisacs invisible. Prostate glands racemose, within xvii-xxii; ducts spherical, enlarged basally, ending at bell-shaped copulatory pouches. Each copulatory pouch with a penial seta. Two pairs of accessory glands attached to copulatory pouches.

Habitats.

The species was collected in the depth of 0-10 cm of sandy soils in bushes and residential gardens.

Vietnamese name.

Giun buồng giao phối hình chuông.

Remarks.

Compared to the original description of M. dorsobitheca by Thai et al. (1992), our specimens differ in minor way: slightly larger size (length: 81-118mm vs 54 mm, diameter: 3.3-3.7 vs 2 mm), more segments (106-142 vs 76), first dorsal pore (12/13 vs 10/11), absence of septum 10/11 (vs presence), the origin of intestine (xv vs xvi), and shape of spermathecal ampulla (sac-shaped vs clavate).

Metaphire dorsobitheca was previously known only in its type locality (Dak No, Dak Lak Province). This is first time that this species has been found elsewhere.

Figures

Figure 10. Metaphire dorsobitheca (Thai et Huynh, 1992) (CTU-EW. 191. h 01) A 1, A 2 Male region, ventral view B 1, B 2 right spermathecae C spermathecal region, dorsal view D 1, D 2 intestinal caecum E Testis sacs and vesicles F 1, F 2 left prostatic gland G transection via copulatory pouch. Scale bar: 1 mm.