Amynthas poropapillatus, Nguyen & Lam & Trinh & Nguyen, 2020

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

Amynthas poropapillatus sp. nov. Fig. 14 , Table 4

Material examined.

Holotype: 1C (CTU-EW.190.h01), Kien Giang Province, Phu Quoc island, natural forests (10°22'53"N, 104°00'22"E), 38 m, 7 November 2016, coll. Trinh TKB.

Paratypes: 9C (CTU-EW.190.p02) same data as for holotype.

Non-types: 11C (CTU-EW.190.03) same data as for holotype.

Diagnosis.

Medium-sized, length 139-170 mm, diameter 4.4-5.8 mm, segments 149-151. Prostomium epilobous. First dorsal pore in 12/13. Two pairs of spermathecal pores in ventral intersegments 7/8/9. Male pores located behind the setal ring xviii, on the posterior edge of genital markings. Two pairs of genital markings present in xvii and xviii. Intestinal caeca simple. Holandric. Testis sacs in xi, separated. Septa 8/9/10/11 absent.

Etymology.

" poropapillatus ", an adjective in apposition, to emphasize the position of male pores on the genital markings.

Description.

Body cylindrical, medium-sized, length 139-170 mm, diameter 4.4-5.8 mm, segments 149-151, weight 1.4-2.2 g. Body uniformly greyish brown except darkish brown clitellum. Prostomium 1/2 epilobous. First dorsal pore in 12/13. Pre-clitellum setae stouter and sparser than post-clitellum ones; setal numbers: 56-59 in viii, 84-85 in xxx, 17-20 between two male porophores in xviii; setal distance: aa = ab, zz = zy. Clitellum xiv-xvi, without setae and dorsal pores. Female pore single, in mid-ventral xiv.

Two pairs of spermathecal pores in intersegments 7/8/9. Male pores behind the setal ring xviii, on the posterior edge of genital markings, without copulatory pouches; ventral distance between two male pores about 0.33 × circumference. Two pairs of genital markings present in xvii and xviii, slightly concave inside body wall.

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 xxii-xxvii. Last hearts in xiii. Pharyngeal micronephridia in 5/6/7. Typhlosole lamelliform. Lymph glands lobuled, from 15/16.

Two pairs of spermathecae in viii and ix. Ampulla clavate, sometimes constricted; ducts short. Diverticula shorter than ampulla, folded several times, attached to the base of ampulla; seminal chamber oval. Each spermatheca with a bean-shaped accessory gland.

Holandric. Testis sacs in xi, separated. Seminal vesicles well developed in xi and xii. Ovaries in 12/13. Ovisacs invisible. Prostatic glands deeply lobuled in xvi-xxi; ducts long. Two pairs of accessory glands present.

Habitats.

The species was found only in natural forests in northern part of Phu Quoc island. It was collected in the upper soil layer (0-10 cm) of clay soils.

Vietnamese name.

Giun nhú phụ chứa lỗ đ ực.

Remarks.

The new species can be assigned to the A. aeruginosus group. Within the A. aeruginosus group, A. poropapillatus sp. nov. is similar to A. nametensis Hong, Inkhavilay & James, 2018 and A. hoauykanangensis Hong, Inkhavilay & James, 2018 in having the spermathecal pores located ventrally, the genital markings paired in xviii, the genital markings in spermathecal region absent, and a simple intestinal caeca. However, these three species can be distinguished by the first dorsal pore, number and position of genital markings in the male region, position of male pores, presence of septa 8/9 and 10/11, and intestinal origin (summarized in Table 4 ).

Figures

Figure 14. Amynthas poropapillatus sp. nov. Holotype (CTU-EW. 190. h 01) A 1, A 2 male region, ventral view B 1, B 2 right prostatic gland C 1, C 2 spermathecal region, ventral view D testis sacs and vesicles E intestinal caecum F 1, F 2 right spermathecae G male pore, ventral view H longitudinal transection via male porophore I transverse transection via male porophore. Scale bar: 1 mm.