Amynthas taoyuanensis 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 taoyuanensis Qiu & Jin sp. nov.

Fig. 3

Material examined.

Holotype. • 1 clitellate ( P 1 CJHUSH 190517069 N 8-01 A ), 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 ( P 1 CJHUSH 190517069 N 8-01 B ), 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 ( P 1 CJHUSH 190526781 R 8-04 ), 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 ( HU 201601-03 ), 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 ( HU 201602-04 ), 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 .

Diagnosis.

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.

External characters.

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 / 3 XVI, smooth, setae numbering 8 at XIV ( P 1 CJHUSH 190517069 N 8-01 and HU 201602-04 ), 11 at XV ( HU 201602-04 ), 13 at XVI ( P 1 CJHUSH 190517069 N 8-01 ) or 14 at XVI ( P 1 CJHUSH 190526781 R 8-04 ), 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 = 1.0–1.4 ab, zz = 1.0–1.4 zy. 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. 3 A ). Sometimes a similar papilla presents in the center of XVII (specimen HU 201601-03 ) (Fig. 3 D ). Sometimes another similar papilla presents in the center of XIX (specimen HU 201602-04 ) (Fig. 3 E ). 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 HU 201601-03 and HU 201602-04 ). Sometimes another pair of similar papillae present in the same position of VIII (specimen P 1 CJHUSH 190526781 R 8-04 ).

Internal characters.

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. 3 B ). 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. 3 C ). Sometimes pair of large lumpy accessory glands present on the ventrum of VII (specimen HU 201601-03 and HU 201602-04 ).

Etymology.

The species is named after its type locality.

Remarks.

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 / 3 XVI, 13 or 14 setae between male pores, the ventral distance of spermathecal pores is 1 / 3 C, 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 / 4 C, 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 ).

Figures

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 (HU 201601-03) E male pores of paratypes (HU 201602-04). Abbreviations: sp, spermathecal pores; mp, male pores.