Holotype. • 1 clitellate (P1CJHUSH190510083 N1-05A), China, Hunan Province, Xiangtan City (27.98312°N, 112.81616°E), 47 m elevation, brownish yellow soil under shrub in farmland, 10 May 2019, JB Jiang, JL Li and BY Yin. Paratypes. 10 clitellates in total • 2 clitellates (P1CJHUSH190510083 N1-05B), China, Hunan Province, Xiangtan City (27.98312°N, 112.81616°E), 47 m elevation, brownish yellow soil under shrub in farmland, 10 May 2019, JB Jiang, JL Li and BY Yin • 2 clitellates (P1CJHUSH190519808 N5-02), China, Hunan Province, Yongzhou City (25.83566°N, 112.27331°E), 163 m elevation, brown soil under weeds in field, 19 May 2019, JB Jiang, JL Li and Y Wang • 2 clitellates (P1CJHUSH190526781 N5-01), China, Hunan Province, Liling City (27.54671°N, 113.54837°E), 74 m elevation, brown soil under weeds in farmland, 26 May 2019, JB Jiang, JL Li and Y Wang • 2 clitellates (P1CJHUSH190514791 N13-01), China, Hunan Province, Yueyang City (29.07035°N, 113.23038°E), 57 m elevation, yellow soil under vegetable field in farmland, 14 May 2019, Y Dong, YF Qin and YZ Wu • 2 clitellates (AH201612-02), China, Anhui Province, Huangshan City (30.58531°N, 117.87033°E), 506 m elevation, brown soil under vegetable field in farmland, 8 May 2016, JB Jiang, J Sun, Y Dong and Y Zheng.

Size medium to large. Spermathecal pores in 5/6–8/9, separated by 1/3 of body circumference. Male pores in XVIII, separated by 1/3 of body circumference, each on the top of a slightly raised, circular porophore. Spermathecae four pairs in VI–IX, ampulla heart-shaped, duct thick and ~ 1/4 of ampulla. Diverticulum is ~ 2/3 of main pouch (duct and ampulla together), terminal 1/2 dilated into rod-shaped seminal chamber. Intestinal caeca are simple. Prostate glands are well developed.

Yellowish brown dorsal pigmentation, pale yellowish brown ventral pigmentation. Dimensions 110–184 mm by 5.0–7.0 mm at clitellum, segments 111–133. Annulus present on VIII–XIII. The dorsal midline is clearly visible and purplish brown. First dorsal pore of all examined individuals in 9/10. Prostomium 1/2 epilobous. Clitellum annular, taupe, in XIV– XVI, swollen, setae invisible externally, but dorsal pores visible on clitellum. Setae numbering 16–28 at III, 26–32 at V, 40–46 at VIII, 46–54 at XX, 54–58 at XXV; 14–16 between male pores; 8–12 (V), 10–12 (VI), 12–14 (VII) and 14–17 (VIII) between spermathecal pores; setal formula, aa = 1.0–1.2ab, zz = 1.4–2.0zy. Male pores one pair in XVIII, separated by 1/3 of body circumference, each on the top of a slightly raised, circular porophore. A pair of oval medium-sized flat-topped papillae on XVIII, after the setae ring near male pores, the interval is ~ 1/4 of body circumference (Fig. 2A). Sometimes another pair of similar papillae present after male pores, the interval is ~ 1/3 of body circumference (specimen P1CJHUSH190519808 N5-02) (Fig. 2E); another pair similar papillae present on the ventrum of XVIII, but near to the ventral line (specimen P1CJHUSH190514791 N13-01) (Fig. 2F). Female pore single in XIV, oval, milky white. Spermathecal pores four pairs in 5/6–8/9, ventral, small eye-like, milky white porophore in center, separated by 1/3 of body circumference. A pair of oval medium-sized flat-topped papillae before the setae ring on the ventrum of IX, the interval of two papillae separated by ~ 1/9 of body circumference (Fig. 2A). Sometimes another pair of similar papillae present on the same position of VIII (specimen P1CJHUSH190526781 N5-01).

Figure 2. 

A. xiangtanensis sp. nov. A ventral view showing spermathecal pores, and male pores B prostate glands C intestinal caeca D spermathecae E male pores of paratypes (P1CJHUSH190519808 N5-02) F male pores of paratypes (P1CJHUSH190514791 N13-01). Abbreviations: sp, spermathecal pores; mp, male pores.

Septa 5/6–7/8 thick and muscular, 10/11–12/13 slightly thickened, 8/9 and 9/10 absent. Gizzard long bucket-shaped, in IX–X. Intestine enlarged distinctly from XV. Intestinal caeca paired in XXVII, extending anteriorly to XXIII, simple, smooth on both sides or sometimes weakly constricted on ventral margin (Fig. 2C). Four esophageal hearts in X–XIII, the latter three are more developed than the first pair. Male sexual system holandric, testis sacs two pairs in X and XI, well developed, left and right lobes separated on the ventral side. Seminal vesicles two pairs in XI and XII, well developed, left and right lobes separated on the ventral side. Prostate glands well developed, inserting in XVIII and extending to XIV and XXI, coarsely lobate, prostatic duct U-shaped, slightly thicker at the distal part, a large lumpy accessory gland beside the prostatic duct (Fig. 2B). Spermathecae four pairs in VI–IX, ampulla heart-shaped, ~ 2.5–4.5 mm long in holotype; ampulla duct is thick and ~ 1/4 of ampulla. Diverticulum is ~ 2/3 of main pouch (duct and ampulla together), slender, terminal 1/2 dilated into rod-shaped seminal chamber. A pair of large lumpy accessory glands present on the ventrum of IX, corresponding to the position of papillae (Fig. 2D). Sometimes another pair of large lumpy accessory glands present on the ventrum of VIII, corresponding to the position of papillae.

The species is named after its type locality.

Amynthas xiangtanensis sp. nov., with four pairs of spermathecal pores in 5/6–8/9, keys to the Amynthas corticis group (Sims and Easton 1972) which consists of 111 species (Nguyen et al. 2020a, 2020b; Sun et al. 2021; Li et al. 2024); it is similar to A. taoyuanensis sp. nov. in setae number, spermathecal pores, male pores, and simple intestinal caeca (Table 2). However, A. xiangtanensis sp. nov. (110–184*5.0–7.0, yellowish brown dorsum and pale yellowish brown ventrum) is easily distinguished from A. taoyuanensis sp. nov. (length 41–120*3.5–4.5, colorless) by its larger body size and pigmentation. In addition, the first dorsal pore of A. xiangtanensis sp. nov. is in 9/10, but 10/11 in A. taoyuanensis sp. nov.; clitellum in XIV–XVI of A. xiangtanensis sp. nov., while XIV–2/3XVI in A. taoyuanensis sp. nov.; paired papillae before setae in VIII or IX in A. xiangtanensis sp. nov., but paired papillae after setae in VI, VII or VIII in A. taoyuanensis sp. nov.; two or more papillae near male pore of A. xiangtanensis sp. nov., whereas two pairs or more in XVI, XVII, XVIII or XIX of A. taoyuanensis sp. nov.; prostate gland well developed in A. xiangtanensis sp. nov., nevertheless prostate glands degenerated in A. taoyuanensis sp. nov.; spermathecae of A. xiangtanensis sp. nov. (~ 2.5–4.5 mm long, ampulla heart-shaped, duct ~ 1/4 of ampulla) are different from A. taoyuanensis sp. nov. (~ 0.6–1.8 mm long, ampulla oval-shaped, duct is thick and ~ 1/2 of ampulla) by size and shape; diverticulum terminal 1/2 dilated into rod-shaped seminal chamber in A. xiangtanensis sp. nov., but terminal 3/4 dilated into bag-shaped seminal chamber in A. taoyuanensis sp. nov.

The new species is also fairly close to Amynthas corticis (Kinberg, 1867) by having medium to large size, spermathecal pores location and simple intestinal caeca (Table 2). However, the new species differs from A. corticis in pigmentation (yellowish brown dorsum and pale yellowish brown ventrum), first dorsal pore in 9/10, paired papillae within spermathecal pore region before setae in VIII or IX, male pores middle and round by 1/3C, two or more papillae near male pore, prostate glands in XIV–XXI with a large lumpy accessory gland, ampulla heart-shaped, diverticulum terminal 1/2 dilated into rod-shaped seminal chamber, paired large lumpy accessory glands on VIII or IX. Whereas A. corticis has a greenish brown dorsum and an unpigmented ventrum, first dorsal pore in 11/12, paired papilla before or after setae in some or all near spermathecal pores, male pores small and circular to transverse elliptical disc by 1/4C–1/3C, one or more papillae near male pore, prostate glands in XVII–XX without accessory glands, ampulla ovoid, diverticulum straight stalked, terminally dilated into a blunt ovoid seminal chamber, accessory glands stalked, coelomic, bound down to the parietes or retained within body wall.

Another similar species with four pairs of spermathecal pores in 5/6–8/9 is Amynthas maximus Qiu & Dong, 2019. The two species share some similarities, such as body size, pigmentation, spermathecal pores, simple intestinal caeca (Table 2). However, A. xiangtanensis sp. nov. has first dorsal pore in 9/10, clitellum XIV–XVI, spermathecal pores, paired papillae before setae in VIII or IX, male pores without ridges, separated by 1/3 of body circumference, two or more papillae near male pore, prostate glands in XIV–XXI with a large lumpy accessory gland, spermathecae larger, ampulla heart-shaped, duct ~ 1/4 of ampulla, diverticulum terminal 1/2 dilated into rod-shaped seminal chamber, paired large lumpy accessory glands on VIII or IX. While A. maximus has first dorsal pore in 13/14, clitellum in 2/5XIV–XVI, fewer setae at VIII and XX, two pairs papillae after setae in VII and VIII, male pores surrounded by 3–4 circular ridges, separated by 2/5 of body circumference, paired papillae before setae medial of male pore, prostate glands in XVII–XIX with accessory glands invisible, spermathecae smaller, ampulla elongate-oval, duct 3/5 of ampulla, diverticulum terminal 2/5 dilated into a swollen, club-shaped seminal chamber, one or two stalked accessory glands on VI, VII, VIII and IX.

Regarding the pigmentation, clitellum, the position of spermathecal and male pores, simple intestinal caeca, and characteristics of the spermathecae, the new species is similar to Amynthas tortuosus Qiu & Dong, 2019. However, the two species are distinguished by body size, the position of the first dorsal pore, setae number, the number and position of papillae within the spermathecal pore and male pore region, the characteristics and ventral distance of male pores, the position of prostate glands and the existence or nonexistence of accessory glands, and the characteristics of the diverticulum and accessory glands (Table 2).

In addition, the new species is somewhat similar to Amynthas stricosus Qiu & Sun, 2012 in the clitellum, the position of spermathecal and male pores, the ventral distance of male pores, and the simple intestinal caeca. Nevertheless, the two species are different in body size, pigmentation, the position of the first dorsal pore, setae number, the ventral distance of spermathecal pores and the existence or nonexistence of papillae, the characteristics of male pores, the number and position of papillae within the male pore region, the position of prostate glands and the existence or nonexistence of accessory glands, the characteristics of spermathecae, diverticulum and existence or nonexistence of accessory glands (Table 2).

Holotype. • 1 clitellate (P1CJHUSH190517069 N8-01A), China, Hunan Province, Yongzhou City (25.30170°N, 111.63432°E), 201 m elevation, brown soil under weeds in dry farmland, 17 May 2019, JB Jiang, JL Li and BY Yin. Paratypes. 7 clitellates in total • 3 clitellates (P1CJHUSH190517069 N8-01B), China, Hunan Province, Yongzhou City (25.30170°N, 111.63432°E), 201 m elevation, brown soil under weeds in dry farmland, 17 May 2019, JB Jiang, JL Li and BY Yin • 1 clitellates (P1CJHUSH190526781 R8-04), China, Hunan Province, Liling City (27.63491°N, 113.54768°E), 55 m elevation, yellow soil under weeds in woodland, 26 May 2019, JB Jiang, JL Li and Y Wang • 2 clitellates (HU201601-03), China, Hunan Province, Changde City (28.70779°N, 111.38225°E), 66 m elevation, brown soil under moss and fern in farmland, 2 May 2016, JB Jiang, J Sun, Y Dong and Y Zheng • 1 clitellates (HU201602-04), China, Hunan Province, Changde City (28.65267°N, 111.34672°E), 69 m elevation, reddish brown soil under moss and fern in farmland, 2 May 2016, JB Jiang, J Sun, Y Dong and Y Zheng.

Size small to medium. Spermathecal pores in 5/6–8/9, separated by 1/3 of body circumference. Male pores in XVIII, separated by 1/3 of body circumference, each on the top of a slightly raised, circular porophore. Spermathecae four pairs in VI–IX, ampulla heart- or rod-shaped, duct is thick and ~ 1/3 of ampulla. Diverticulum is ~ 3/4 of main pouch (duct and ampulla together), terminal 3/4 dilated into bag-shaped chamber intestinal caeca are simple. Prostate glands are degenerated.

No pigmentation on dorsal and ventral. Dimensions 41–120 mm by 3.5–4.5 mm at clitellum, segments 49–112. Annulus present on X–XIII. The dorsal midline is clearly visible and green-brown. First dorsal pore of all examined individuals in 10/11. Prostomium 1/2 epilobous. Clitellum annular, grey, in XIV–2/3XVI, smooth, setae numbering 8 at XIV (P1CJHUSH190517069 N8-01 and HU201602-04), 11 at XV (HU201602-04), 13 at XVI (P1CJHUSH190517069 N8-01) or 14 at XVI (P1CJHUSH190526781 R8-04), dorsal pores visible on clitellum. Setae numbering 32–42 at III, 40–48 at V, 44–50 at VIII, 50–58 at XX, 56–62 at XXV; 13–14 between male pores; 18–19 (V), 18–21 (VI), 19–21 (VII) and 19–22 (VIII) between spermathecal pores; setal formula, aa = 1.0–1.4ab, zz = 1.0–1.4zy. Male pores one pair in XVIII, separated by 1/3 body circumference, each on the top of a slightly raised, circular porophore. Two pairs of circular medium-sized flat-topped papillae present after the setae ring in XVI and XVII, the interval is ~ 1/3 of body circumference. Two pairs of circular medium-sized flat-topped papillae present before the setae ring on XVII and XVIII, the interval is ~ 1/9 of body circumference (Fig. 3A). Sometimes a similar papilla presents in the center of XVII (specimen HU201601-03) (Fig. 3D). Sometimes another similar papilla presents in the center of XIX (specimen HU201602-04) (Fig. 3E). Female pore single in XIV, oval, milky white. Spermathecal pores four pairs in 5/6–8/9, ventral, small eye-like, milky white porophore in center, separated by 1/3 body circumference. A pair of oval medium-sized flat-topped papillae after the setae ring between the spermathecal pores in VII, the interval is ~ 1/4 of body circumference. Sometimes another pair of similar papillae present in the same position of VI (specimen HU201601-03 and HU201602-04). Sometimes another pair of similar papillae present in the same position of VIII (specimen P1CJHUSH190526781 R8-04).

Figure 3. 

A. taoyuanensis sp. nov. A ventral view showing spermathecal pores, and male pores B intestinal caeca C spermathecae D male pores of paratypes (HU201601-03) E male pores of paratypes (HU201602-04). Abbreviations: sp, spermathecal pores; mp, male pores.

Septa 5/6–7/8 thick and muscular, 10/11–12/13 slightly thickened, 8/9 and 9/10 absent. Gizzard spherical, in IX–X. Intestine enlarged distinctly from XV. Intestinal caeca paired in XXVII, extending anteriorly to XXIV, simple, smooth on both sides (Fig. 3B). Four esophageal hearts in XI–XIII, well developed. Male sexual system holandric, testis sacs two pairs, in X and XI, well developed, left and right lobes separated on the ventral side. Seminal vesicles two pairs, extending in XI and XII, well developed, left and right lobes separated on the ventral side. Prostate glands degenerated, prostatic duct U-shaped inserting in XVIII, several small lumpy accessory glands in center of ventral XVI, XVII, and XVIII; the position is consistent with the position of the ventral mastoid on the body surface. Spermathecae four pairs in VI–IX, ampulla oval-shaped, ~ 0.6–1.8 mm long in holotype; ampulla duct is thick and ~ 1/2 of ampulla. Diverticulum is ~ 2/3 of main pouch (duct and ampulla together), terminal 3/4 dilated into bag-shaped chamber. Two pairs of large lumpy accessory glands present on the ventrum of VII and VIII (Fig. 3C). Sometimes pair of large lumpy accessory glands present on the ventrum of VII (specimen HU201601-03 and HU201602-04).

The species is named after its type locality.

Amynthas taoyuanensis sp. nov., with four pairs of spermathecal pores in 5/6–8/9, also belongs to the Amynthas corticis group. Amynthas taoyuanensis sp. nov. is close to Amynthas xiangtanensis sp. nov. in setae number, the position and characteristics of spermathecal pores and male pores, and the simple intestinal caeca. However, the differences between the two new species are body size, pigmentation, the position of the first dorsal pore, the position of clitellum, the position of papillae within spermathecal pores and male pore region, the existence or nonexistence of prostate glands, and the characteristics of the spermathecae and diverticulum (Table 2).

The new species is similar to Amynthas homosetus (Chen, 1938) in terms of body size, position and characteristics of spermathecal pores and male pores, and simple intestinal caeca. Whereas, the new species differs from A. homosetus in being unpigmented, the first dorsal pore in 10/11, clitellum in XIV–2/3XVI, 13 or 14 setae between male pores, the ventral distance of spermathecal pores is 1/3C, papillae paired after setae in VI, VII, or VIII, two paired or more papillae in XVI, XVII, XVIII, or XIX, prostate glands degenerated, spermathecae ~ 0.6–1.8 mm long, ampulla oval-shaped, duct is thick and ~ 1/2 of ampulla, diverticulum terminal 3/4 dilated into bag-shaped seminal chamber, two paired large lumpy accessory glands on VII or VIII. Amynthas homosetus is dark chocolate-colored anteriorly and grey on other parts of dorsum, grey on the ventrum, the first dorsal pore in 12/13, clitellum without setae in XIV–XVI, nine setae between male pores, the ventral distance of spermathecal pores is 1/4C, papillae invisible within spermathecal pores and male pore regions, prostate glands developed in XVI–XXI, spermathecae heart-shaped, diverticulum seminal chamber ovoid (Table 2).

Amynthas taoyuanensis sp. nov. is also close to Amynthas stricosus Qiu & Sun, 2012 by body size, pigmentation, setae number, the characteristics of spermathecal pores and male pores, the ventral distance of male pores, simple intestinal caeca. However, the new species is distinguished from A. stricosus by the first dorsal pore, the position and existence or nonexistence setae of clitellum, and the ventral distance of spermathecal pores; A. taoyuanensis sp. nov. has paired papillae after setae in VI, VII, or VIII, but A. stricosus has no papillae; in addition, A. taoyuanensis sp. nov. has two paired papillae or more in XVI, XVII, XVIII, or XIX, but A. stricosus has a single or paired after setae in XVII, XIX, and XX; prostate glands of A. taoyuanensis sp. nov. are degenerated with several lumpy accessory glands in XVI, XVII, and XVIII, while developed in XVI–XX with accessory glands invisible in A. stricosus; furthermore, spermathecae of A. taoyuanensis sp. nov. are ~ 0.6–1.8 mm long, ampulla oval-shaped, duct is thick and ~ 1/2 of ampulla, whereas ~ 1.6 mm long, ampulla heart-shaped, gradually slender duct as long as ampulla in A. stricosus; diverticulum of A. taoyuanensis sp. nov. is ~ 3/4 of main pouch, terminal 3/4 dilated into bag-shaped seminal chamber, but as long as main pouch, slender, terminal 2/5 dilated into band-shaped seminal chamber in A. stricosus; two paired large lumpy accessory glands on VII or VIII in A. taoyuanensis sp. nov., but no accessory glands in A. stricosus (Table 2).

According to body size, pigmentation, setae ventrally in clitellum, the position and characteristics of spermathecal pores and male pores, simple intestinal caeca, and the characteristics of spermathecae, A. taoyuanensis sp. nov. is somewhat similar to Amynthas genitalis Qiu & Sun, 2012. However, the new species is characterized by the first dorsal in 10/11, clitellum in XIV–2/3 XVI, 19–22 setae between spermathecal pores (VIII), papillae paired within spermathecal pore region, two paired or more papillae in XVI, XVII, XVIII, or XIX, prostate glands degenerated with several lumpy accessory glands in XVI, XVII, and XVIII, diverticulum ~ 3/4 of main pouch, terminal 3/4 dilated into bag-shaped seminal chamber, two paired large lumpy accessory glands on VII or VIII; whereas A. genitalis has 8–11 setae between spermathecal pores (VIII), no papillae within spermathecal pore region, paired papillae before setae annulet in XVIII and XIX, after setae annulet in XVII and XVII, prostate glands developed with accessory glands invisible in XVII–XX, diverticulum longer than main pouch, slender, terminal 0.29 dilated into rod-shaped seminal chamber, no accessory glands (Table 2).

Another similar species with four pairs of spermathecal pores in 5/6–8/9 is Amynthas recavus Yuan & Jiang, 2019. The two species share some similarities, such as the position of male pores and simple intestinal caeca. However, the two species are distinguished by body size, pigmentation, the first dorsal pore position, setae number, the ventral distance of spermathecal pores, existence or nonexistence of papillae within spermathecal pore region, the characteristics of male pores and papillae within male pore region, prostate glands, the characteristics of spermathecae and diverticulum, and the existence or nonexistence of accessory glands (Table 2).

Holotype. • 1 clitellate (AH201517-06), China, Anhui Province, Xuancheng City (30.89694°N, 118.48889°E), 860 m elevation, black sandy soil under shrubbery in front of the house, 11 October 2015, Y Dong, Z Yuan, MS Chen and YL Wang. Paratype. • 1 clitellate (P1CJHUSH190521800 Q6-03), China, Hunan Province, Chenzhou City (26.16809°N, 113.05648°E), 79 m elevation, sandy soil under weeds beside roadways, 21 May 2019, JB Jiang, JL Li and Y Wang.

Size small. Spermathecal pores in 5/6 and 6/7, separated by 1/3 of body circumference. Male pores in XVIII, separated by 1/4 of body circumference, each on the top of a slightly raised, circular porophore. Spermathecae two pairs in VI and VII, ampulla heart-shaped, duct is thick and ~ 1/2 of ampulla. Diverticulum as long as main pouch (duct and ampulla together), terminal 1/2 dilated into ovoid-shaped seminal chamber. Intestinal caeca are simple. Prostate glands are developed.

No dorsal or ventral pigmentation. Dimensions 26–32 mm by 1.5–2.0 mm at clitellum, segments 60–65. The dorsal midline is not clearly visible. First dorsal pore of all examined individuals in 12/13. Prostomium 1/2 epilobous. Clitellum annular, taupe, in XIV– XVI, smooth, setae invisible externally. Setae numbering 32–40 at III, 36–44 at V, 40–48 at VIII, 50–54 at XX, 56–58 at XXV; 4 between male pores; setal formula, aa = 1.0–1.4ab, zz = 1.4–2.0zy. Male pores one pair in XVIII, separated by 1/4 body circumference, each on the top of a slightly raised, circular porophore (Fig. 4A). Female pore single in XIV, oval, milky white. Spermathecal pores two pairs in 5/6 and 6/7, ventral, not clearly, milky white porophore in center, separated by 1/3 body circumference.

Figure 4. 

A. xuanchengensis sp. nov. A ventral view showing spermathecal pores, and male pores B prostate glands C intestinal caeca D spermathecae. Abbreviations: sp, spermathecal pores; mp, male pores.

Figure 5. 

M. donganensis sp. nov. A ventral view showing spermathecal pores, and male pores B prostate glands C intestinal caeca D male pores of paratype (P1CJHUSH190511779 N9-03) E spermathecae. Abbreviations: sp, spermathecal pores; mp, male pores.

Septa 5/6–7/8 thick and muscular, 10/11–12/13 slightly thickened, 8/9 and 9/10 absent. Gizzard spherical in IX–X. Intestine enlarged distinctly from XV. Intestinal caeca paired in XXVII, extending anteriorly to XXVI, simple, smooth on both sides (Fig. 4C). Four esophageal hearts in X–XIII, not well developed. Male sexual system holandric, testis sacs two pairs, in X and XI, well developed, left and right lobes separated on the ventral side. Seminal vesicles two pairs, extending in XI and XII, well developed, left and right lobes separated on the ventral side. Prostate glands well developed, inserting in XVIII and extending to XVI and XIX, coarsely lobate, prostatic duct U-shaped, slightly thicker at the distal part (Fig. 4B). No accessory glands observed. Spermathecae two pairs in VI–VII, ampulla heart-shaped, ~ 0.7 mm long in holotype; ampulla duct is thick and ~ 1/2 of ampulla. Diverticulum as long as main pouch (duct and ampulla together), terminal 1/2 dilated into ovoid-shaped seminal chamber. No accessory glands observed (Fig. 4D).

The species is named after its type locality.

Amynthas xuanchengensis sp. nov., with two pairs of spermathecal pores in 5/6 and 6/7, can be assigned to Amynthas morrisi group (Sims and Easton 1972) with 55 species included in this group (Sun et al. 2009, 2015, 2021; Shen et al. 2014; Jiang et al. 2015; Hong 2017), such as Amynthas nanulus (Chen & Yang, 1975) (Chen et al. 1975), Amynthas parvus (Chen & Hsu, 1977), Amynthas piagolensis Hong & James, 2001, Amynthas diaoluomontis Qiu & Sun, 2009, Amynthas endophilus Zhao & Qiu, 2013. Amynthas xuanchengensis sp. nov. is very similar to Amynthas endophilus Zhao & Qiu, 2013 by lacking pigmentation, first dorsal pore in 12/13, clitellum in XIV–XVI, the position of spermathecal pores and male pores, no papillae within spermathecal pore and male pore regions, simple intestinal caeca. However, the new species differs from A. endophilus by smaller body size and fewer setae. And beyond that, the ventral distance of spermathecal pores and male pores is 1/3C and 1/4C in A. xuanchengensis sp. nov., but 2/5C and 1/3C in A. endophilus; spermathecal pores of A. xuanchengensis sp. nov. are inconspicuous, but obvious in A. endophilus; male pores of A. xuanchengensis sp. nov. not surrounded by folds, but A. endophilus surrounded by four folds; prostate glands in XVI–XIX in A. xuanchengensis sp. nov., but XVII–XXI in A. endophilus; spermathecae ~ 0.7 mm long, ampulla heart-shaped, duct is thick and ~ 1/2 of ampulla of A. xuanchengensis sp. nov., while spermathecae longer, ampulla elongated ovoid, duct a little shorter than ampulla in A. endophilus; diverticulum as long as main pouch in A. xuanchengensis sp. nov., nevertheless shorter than main pouch in A. endophilus (Table 3).

Another similar species with two pairs of spermathecal pores in 5/6 and 6/7 is Amynthas fucatus Zhao & Qiu, 2013. The two species share some similarities, such as clitellum in XIV–XVI, the position of spermathecal pores and male pores, invisible papillae within spermathecal pore region, and simple intestinal caeca. By contrast, the new species and A. fucatus can be separated on the basis of smaller body size and fewer setae at VIII. In addition, A. xuanchengensis sp. nov. is unpigmented, but dark red brown before clitellum and pale after clitellum in dorsum, pale red brown before clitellum and pale after clitellum in ventrum in A. fucatus; the first dorsal pore of A. xuanchengensis sp. nov. in 12/13, but 11/12 in A. fucatus; the ventral distance of spermathecal pores and male pores are 1/3C and 1/4C in A. xuanchengensis sp. nov., but 2/5C and 2/5C in A. fucatus; spermathecal pores of A. xuanchengensis sp. nov. are inconspicuous, but obvious in A. fucatus; male pores of A. xuanchengensis sp. nov. not surrounded by folds, but A. fucatus surrounded by three to five folds; invisible papillae within male pore region of A. xuanchengensis sp. nov., whereas two papillae on the inner side of male pore, another paired in XVIII in A. fucatus; prostate glands in XVI–XIX of A. xuanchengensis sp. nov., while XV–XXI with accessory glands invisible in A. fucatus; spermathecae ~ 0.7 mm long, ampulla heart-shaped in A. xuanchengensis sp. nov., nevertheless spermathecae longer, ampulla elongated ovoid in A. fucatus; diverticulum is as long as main pouch, terminal 1/2 dilated into ovoid-shaped seminal chamber in A. xuanchengensis sp. nov., but diverticulum ~ 1/3 of main pouch, straight, terminal 3/4 dilated into virgulate seminal chamber in A. fucatus (Table 3).

Amynthas xuanchengensis sp. nov. appears to be closely related to A. infuscuatus Jiang & Sun, 2015 in the combined characters of ventrum pigmentation, first dorsal pore in 12/13, clitellum in XIV–XVI, the position and characteristics of spermathecal pores, invisible papillae within spermathecal pore region, the position of male pores, simple intestinal caeca, and ampulla heart-shaped. Conversely, they still have some differences, such as body size, dorsum pigmentation, and setae number. Amynthas xuanchengensis sp. nov. smaller, without pigment on dorsum, but purple before VIII; pale brown after VIII in A. infuscuatus; four setae between male pores of A. xuanchengensis sp. nov., but 8–10 setae in A. infuscuatus; the ventral distance of male pores is 1/4C in A. xuanchengensis sp. nov., but 1/3C in A. infuscuatus; spermathecal pores of A. xuanchengensis sp. nov. are inconspicuous, but obvious in A. infuscuatus; male pores of A. xuanchengensis sp. nov. surrounded by no folds, but A. infuscuatus surrounded by three or four folds; invisible papillae within male pore region of A. xuanchengensis sp. nov., whereas two papillae on the inner side of male pore in A. infuscuatus; prostate glands in XVI–XIX of A. xuanchengensis sp. nov., while XVI–1/2XX with accessory glands invisible in A. infuscuatus; spermathecae ~ 0.7 mm long, duct is thick and ~ 1/2 of ampulla in A. xuanchengensis sp. nov., but spermathecae longer, duct slender, twice as long as ampulla in A. infuscuatus; diverticulum is as long as main pouch, terminal 1/2 dilated into ovoid-shaped seminal chamber in A. xuanchengensis sp. nov., but diverticulum longer than main pouch, slender, terminal 1/3 dilated into swollen seminal chamber in A. infuscuatus (Table 3).

Amynthas xuanchengensis sp. nov. and Amynthas zonarius Sun & Qiu, 2015 share some common characters in pigmentation, first dorsal pore in 12/13, clitellum in XIV–XVI, the characteristics of spermathecal pores, invisible papillae within spermathecal pore region, the position of male pores, simple intestinal caeca. In contrast, A. xuanchengensis sp. nov. differs from A. zonarius in smaller body size and fewer setae. Additionally, the ventral distance of spermathecal pore and male pores are 1/3C and 1/4C in A. xuanchengensis sp. nov., but 2/5C and 1/3C in A. zonarius; male pores of A. xuanchengensis sp. nov. surrounded by no folds, but A. zonarius surrounded by five folds; invisible papillae within male pore region of A. xuanchengensis sp. nov. whereas one or two papillae on the inner side of male pore, sometimes another two on XVIII in A. zonarius; prostate glands in XVI–XIX in A. xuanchengensis sp. nov., while XVI–1/2XX with accessory glands invisible in A. zonarius; spermathecae ~ 0.7 mm long, ampulla heart-shaped, duct is thick and ~ 1/2 of ampulla in A. xuanchengensis sp. nov., whereas spermathecae longer, ampulla ovoid, duct as long as ampulla in A. zonarius; ovoid-shaped seminal chamber in A. xuanchengensis sp. nov., but band-shaped seminal chamber in A. zonarius (Table 3).

In terms of pigmentation, clitellum, setae number, the positions of spermathecal pores and male pores, inconspicuous spermathecal pores, invisible papillae within spermathecal pore and male pore regions, simple intestinal caeca. Amynthas xuanchengensis sp. nov. is somewhat similar to Amynthas baikmudongensis Hong, 2017. On the contrary, the new species is easily distinguished from A. baikmudongensis by body size, prostate glands, the characteristics of male pores, spermathecae, and diverticulum (Table 3).

Holotype. • 1 clitellate (HU201613-01A), China, Hunan Province, Dongan City (26.35499°N, 111.19531°E), 172 m elevation, brown soil under vegetable field in farmland, 4 May 2016, JB Jiang, J Sun, Y Dong, and Y Zheng. Paratypes. 13 clitellates in total • 1 clitellate (HU201613-01B), China, Hunan Province, Dongan City (26.35499°N, 111.19531°E), 172 m elevation, brown soil under vegetable field in farmland, 4 May 2016, JB Jiang, J Sun, Y Dong and Y Zheng • 2 clitellates (P1CJHUSH190511779 N9-03), China, Hunan Province, Liuyang City (28.32795°N, 113.52008°E), 112 m elevation, red soil under vegetable in vegetable garden, 11 May 2019, Y Dong, YF Qin and YZ Wu • 7 clitellates (P1CJHUSH190512778 N11-01), China, Hunan Province, Yueyang City (28.91995°N, 113.70132°E), 179 m elevation, brown soil under rape in rape field, 12 May 2019, Y Dong, YF Qin and YZ Wu • 1 clitellate (P1CJHUSH190512096 Q3-04), China, Hunan Province, Linxiang City (29.33550°N, 113.40176°E), 51 m elevation, brown sandy soil under shrub in grove, 12 May 2019, Y Dong, YF Qin and YZ Wu • 2 clitellates (P1CJHUSH190518092 Q6-01), China, Hunan Province, Yuanjiang City (29.04369°N, 112.29798°E), 48 m elevation, brown soil under litter next to the house, 18 May 2019, Y Dong, YF Qin and YK Li.

Size medium to large. Spermathecal pores in 6/7–8/9, separated by 1/3 of body circumference. Male pores in XVIII, separated by 1/3 of body circumference, each on the bottom center of the longitudinal copulatory chamber. Sometimes the copulatory chamber eversion is ridged. Spermathecae three pairs in VII–IX, ampulla heart- or rod-shaped, duct thick and as long as ampulla. Diverticulum as long as main pouch (duct and ampulla together), slender and straight at proximal part, terminal 1/2 dilated into twisted in zigzag fashion. Intestinal caeca are simple. Prostate glands are well developed.

Pale brown dorsal and ventral pigmentation. Dimensions 72–159 mm by 4.6–7.0 mm at clitellum, segments 78–111. Annulus present on IX–XVIII. The dorsal midline is clearly visible and purplish brown. First dorsal pore of all examined individuals in 12/13. Prostomium 1/2 epilobous. Clitellum annular, pale taupe, in XIV– XVI, smooth, setae invisible externally. Setae numbering 20–34 at III, 20–46 at V, 28–58 at VIII, 52–66 at XX, 58–70 at XXV; 8–13 between male pores; 14–17 (VI), 16–20 (VII) and 17–21 (VIII) between spermathecal pores; setal formula, aa = 1.0–1.6ab, zz = 1.2–1.8zy. Male pores one pair in XVIII, separated by 1/3 body circumference, each on the bottom center of the longitudinal copulatory chamber, multiple radioactive folds on the outer edge (Fig. 5A). Sometimes the copulatory chamber eversion is ridged (specimen P1CJHUSH190511779 N9-03, P1CJHUSH190512096 Q3-04 and P1CJHUSH190518092 Q6-01) (Fig. 5D). Female pore single in XIV, oval, milky white. Spermathecal pores three pairs in 6/7–8/9, ventral, large eye-like, milky white porophore in center, separated by 1/3 body circumference.

Septa 5/6–7/8 thick and muscular, 10/11–12/13 slightly thickened, 8/9 and 9/10 absent. Gizzard spherical, in IX–X. Intestine enlarged distinctly from XV. Intestinal caeca paired in XXVII, extending anteriorly to XXIII, simple, smooth dorsal margin, weakly constricted on ventral margin (Fig. 5C). Four esophageal hearts in X–XIII, the latter three are more developed than the first pair. Male sexual system holandric, testis sacs two pairs, in X and XI, well developed, left and right lobes connected on the ventral side. Seminal vesicles two pairs, extending in XI and XII, well developed, left and right lobes separated on the ventral side. Prostate glands well developed, inserting in XVIII and extending to XVI and XXII, strip lobate, prostatic duct U-shaped, slightly thicker at the distal part (Fig. 5B). No accessory glands observed. Spermathecae three pairs in VII–IX, ampulla heart- or rod-shaped, ~ 3.2–8.0 mm long in holotype; ampulla duct is swollen and as long as ampulla. Diverticulum as long as main pouch (duct and ampulla together), slender and straight at proximal part, terminal 1/2 dilated into twisted in zigzag fashion. No accessory glands observed (Fig. 5E).

The species is named after its type locality.

Metaphire donganensis sp. nov. with three pairs spermathecal pores in 6/7–8/9, keys to the Metaphire houlleti group, which includes 44 species (Sims and Easton 1972; Feng 1984; Feng and Ma 1987; Qiu and Zhong 1993; Sun et al. 2018). Metaphire vulgaris agricola (Chen, 1930) is slightly akin to the new species in the respects of body size, first dorsal pore in 12/13, clitellum in XIV–XVI, setae number, the position and characteristics of spermathecal pores, simple intestinal caeca, and the characteristics of diverticulum. Instead, the difference between the two species is in the pigmentation, pale brown in M. donganensis sp. nov., earthy yellow in M. vulgaris agricola (Feng, 1981). Further, the ventral distance of spermathecal pore and male pores are 1/3C and 1/3 C in M. donganensis sp. nov., but 1/4C and 1/4C in M. vulgaris agricola; no papillae within spermathecal pore region of M. donganensis sp. nov., but paired papillae in VII of M. vulgaris agricola; no papillae within male pore region of M. donganensis sp. nov., while paired papillae on the inner side of male pore in M. vulgaris agricola; prostate glands well developed in XVI–XXII of M. donganensis sp. nov., nevertheless in XVII–XX with accessory glands invisible in M. vulgaris agricola; spermathecae ~ 3.2–8.0 mm long, ampulla heart- or rod-shaped, duct swollen, as long as ampulla of M. donganensis sp. nov., while spermathecae ~ 4.5 mm long, ampulla pear-shaped, ampulla duct 1/2 of ampulla in M. vulgaris agricola; no accessory glands in M. donganensis sp. nov., while paired accessory glands in the VIII of M. vulgaris agricola (Table 4).

We compare the new species to Metaphire tschiliensis lanzhouensis (Feng, 1984), which has three pairs of spermathecal pores in 6/7–8/9. They share several common characters in the first dorsal pore position, clitellum in XIV–XVI, setae number, the position of spermathecal pores, the position and characteristics of male pores, no papillae within spermathecal pore region, simple intestinal caeca, and the characteristics of the diverticulum. Quite the contrary, the new species is smaller than M. tschiliensis lanzhouensis. Beyond that, coloration is pale brown in M. donganensis sp. nov., earthy yellow in M. tschiliensis lanzhouensis; spermathecal pores are obvious in M. donganensis sp. nov., but inconspicuous in M. tschiliensis lanzhouensis; no papillae within male pore region of M. donganensis sp. nov., but one in pouch of M. tschiliensis lanzhouensis; prostate glands well developed in XVI–XXII of M. donganensis sp. nov., while underdeveloped in XVII–XIX with a large lumpy accessory gland in M. tschiliensis lanzhouensis; spermathecae ~ 3.2–8.0 mm long, ampulla heart- or rod-shaped of M. donganensis sp. nov., but spermathecae ~ 4 mm long, ampulla spherical-shaped in M. tschiliensis lanzhouensis (Table 4).

Considering the three pairs of spermathecal pores in 6/7–8/9, we compared the new species with Metaphire viridis Feng & Ma, 1987. Both have first dorsal pores in 12/13, clitellum in XIV–XVI, the same position and characteristics of spermathecal pores, simple intestinal caeca, and the same characteristics of diverticulum. However, the new species differs from M. viridis in many respects. Metaphire donganensis sp. nov. is smaller than M. viridis with pale brown coloration; setae number of M. donganensis sp. nov. is less than M. viridis; the ventral distance of spermathecal pore and male pores are 1/3C and 1/3 C in M. donganensis sp. nov., but 1/2C and 1/2C in M. viridis; no papillae within spermathecal pore region of M. donganensis sp. nov., while paired in VII, VIII, and IX of M. viridis; no papillae within male pore region of M. donganensis sp. nov., but four in pouches in M. viridis; prostate glands in XVI–XXII of M. donganensis sp. nov., while XV–XX or XVII–XIX with a lumpy accessory gland in M. viridis; no accessory glands in M. donganensis sp. nov., whereas paired in the VII, VIII and IX of M. viridis; spermathecae ~ 3.2–8.0 mm long, ampulla heart- or rod-shaped of M. donganensis sp. nov., nevertheless spermathecae ~ 4 mm long, ampulla spherical- or oval-shaped in M. viridis; no accessory glands of M. donganensis sp. nov., while paired in VII, VIII, and IX of M. viridis (Table 4).

We also compare the new species with Metaphire ptychosiphona Qiu & Zhong, 1993 on the basis of the position and characteristics of male pores, no papillae within spermathecal pore and male pore regions, simple intestinal caeca, and the same characteristics of the diverticulum. Nevertheless, the new species is smaller than M. ptychosiphona. In addition, pale brown in M. donganensis sp. nov., but grey brown in M. ptychosiphona; first dorsal pore in 12/13 of M. donganensis sp. nov., while in 11/12 of M. ptychosiphona; setae number of M. donganensis sp. nov. less than M. ptychosiphona; the ventral distance of spermathecal pore is 1/3C in M. donganensis sp. nov., but 2/5C in M. ptychosiphona; spermathecal pores obvious in M. donganensis sp. nov., but inconspicuous in M. ptychosiphona; prostate glands in XVI–XXII of M. donganensis sp. nov., while XVI–XVIII or XVII–XIX in M. ptychosiphona; and spermathecae ~ 3.2–8.0 mm long, ampulla heart- or rod-shaped, duct swollen, as long as ampulla in M. donganensis sp. nov., nevertheless spermathecae shorter, ampulla rod-shaped, duct shorter than ampulla in M. ptychosiphona (Table 4).

The new species is also close to Metaphire sanmingensis Sun & Jiang, 2018 in body size, clitellum in XIV–XVI, the position of spermathecal pores and male pores, simple intestinal caeca, prostate glands, and the characteristics of the ampulla and diverticulum. However, the new species is easily distinguished from M. sanmingensis in pigmentation, first dorsal pore position, setae number, papillae within spermathecal pore region, and the characteristics of male pores and papillae within male pore region (Table 4).