Amynthas xiangtanensis Qiu & Jin, 2024

Jin, Qing, Li, Jiali, Jiang, Jibao & Qiu, Jiangping, 2024, Four new earthworm species of the genera Amynthas and Metaphire (Oligochaeta, Megascolecidae) from Hunan and Anhui provinces, China, ZooKeys 1210, pp. 247-271 : 247-271

Amynthas xiangtanensis Qiu & Jin sp. nov.

Fig. 2

Material examined.

Holotype. • 1 clitellate ( P 1 CJHUSH 190510083 N 1-05 A), 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 ( P 1 CJHUSH 190510083 N 1-05 B), 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 ( P 1 CJHUSH 190519808 N 5-02 ), 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 ( P 1 CJHUSH 190526781 N 5-01 ), 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 ( P 1 CJHUSH 190514791 N 13-01 ), 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 ( AH 201612-02 ), 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 .

Diagnosis.

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.

External characters.

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 = 1.0–1.2 ab, zz = 1.4–2.0 zy. 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. 2 A ). Sometimes another pair of similar papillae present after male pores, the interval is ~ 1 / 3 of body circumference (specimen P 1 CJHUSH 190519808 N 5-02 ) (Fig. 2 E ); another pair similar papillae present on the ventrum of XVIII, but near to the ventral line (specimen P 1 CJHUSH 190514791 N 13-01 ) (Fig. 2 F ). 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. 2 A ). Sometimes another pair of similar papillae present on the same position of VIII (specimen P 1 CJHUSH 190526781 N 5-01 ).

Internal characters.

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. 2 C ). 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. 2 B ). 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. 2 D ). Sometimes another pair of large lumpy accessory glands present on the ventrum of VIII, corresponding to the position of papillae.

Etymology.

The species is named after its type locality.

Remarks.

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. 2020 a, 2020 b; 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 / 3 XVI 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 / 3 C, 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 / 4 C – 1 / 3 C, 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 / 5 XIV – 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 ).

Figures

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 (P 1 CJHUSH 190519808 N 5-02) F male pores of paratypes (P 1 CJHUSH 190514791 N 13-01). Abbreviations: sp, spermathecal pores; mp, male pores.