Two new species of earthworms belonging to the genus Amynthas (Oligochaeta: Megascolecidae) from Guangxi Province, China Author Dong, Yan Author Yuan, Zhu Author Jiang, Jibao Author Zhao, Qi Author Qiu, Jiangping text Zootaxa 2018 2018-10-05 4496 1 259 268 journal article 29263 10.11646/zootaxa.4496.1.21 926b74cb-c009-4c03-8dcf-4acf8daf98b5 1175-5326 1446797 AB9A1D53-0811-4FC8-8F6C-DD13C3E79451 Amynthas stabilis Dong & Jiang , sp. nov. ( Figure 2 , Table 3) Material. Holotype . Clitellate specimen (C-GX201305-06A), China , Guangxi Province, Shiwan Mountain Nature Reserve, N 21.50396° , E 107.53350° , 494 m asl, red sandy soil under bryophytes besides road, 13th May , 2013, J. P. Qiu, Y, Hong, J. B. Jiang, L. L. Zhang and Y. Dong coll. Paratypes . 4 clitellate specimens, C-GX201305-06B, same date as for holotype . Etymology. The species is named after its stable number, location and size of genital papillae in spermathecal pore and male pore region. Diagnosis. Dimensions 61–68 mm by 3.0– 3.2 mm at clitellum, segments 87–103. First dorsal pore in 12/13. Setae numbering 10–14 at?, 17–20 at?, 23–26 at?, 36–38 at XX, 32–38 at XXV; 6–8 between male pores; 6–8 at VII, 6 at? between spermathecal pores. Spermathecal pores three pairs in 6/7–8/9. Four presetal genital papillae in VIII and IX, 0.25 circumference ventrally apart from each other ( Fig. 2A ). Male pores one pair in XVIII, 0.33 circumference apart ventrally, each on the top of an elliptic porophore surrounded by 1–2 circular ridges, with four big intersegmental genital papillae at 17/18 and 18/19, flat-topped and collapsed in the middle, 0.25 circumference apart ventrally ( Fig. 2B ). Ampulla elongate, oval-shaped, stout duct, as long as 1/2 ampulla. Diverticulum slightly shorter than main pouch, terminal 1/4 dilated into a club-shaped seminal chamber ( Fig. 2C ). Prostate glands welldeveloped ( Fig. 2D ). No accessory glands observed in male pore region. External characters. Tan pigment on middle dorsum of the whole body, no pigment on ventral and lateral sides. Dimensions 61–68 mm by 3.0– 3.2 mm at clitellum, segments 87–103. Prostomium 1/2 epilobous. First dorsal pore in 12/13. Setae numbering 10–14 at?, 17–20 at?, 23–26 at?, 36–38 at XX, 32–38 at XXV; 6–8 between male pores; 6–8 at VII, 6 at? between spermathecal pores. Setae formula: AA=1.4–2.2AB, ZZ=3.6–4.0ZY. Clitellum annular, in XIV–XVI, setae invisible externally. Spermathecal pores three pairs in 6/7–8/ 9, small. Four presetal genital papillae observed in VIII and IX, 0.33 circumference ventrally apart from each other. Male pores one pair in XVIII, 0.33 circumference apart ventrally, each on the top of an elliptic porophore surrounded by 1–2 circular ridges, with four big intersegmental collapse-topped genital papillae between XVII–XIX, 0.33 circumference apart ventrally. Female pore single in XIV. Internal characters. Septa 5/6–7/8 thick, 10/11–13/14 slightly thickened, 8/9–9/10 absent. Gizzard bucketshaped, in IX–XI. Intestine enlarged distinctly from XV. Intestinal caeca paired in XXVII, simple, smooth, extending anteriorly to XXII. Esophageal hearts in X–XIII, the first pair tiny, the last three pairs developed. Ovaries in IX. Spermathecae three pairs in VII–IX, small, about 1.5 mm long. Ampulla long oval-shaped, stout duct as long as 1/2 ampulla. Diverticulum a little shorter than main pouch (ampulla and duct), terminal 1/4 dilated into a club-shaped seminal chamber ( Figure 2B ). One nubbly accessory gland observed near the distal part of the last two pair spermathecal duct. Holandric: Testis sacs two pairs, in X–XI, well-developed. Seminal vesicles two pairs, in XI–XII. Prostate glands well-developed, inserting in XVIII and extending from 1/2XV to XX, nubbly lobate, prostate duct U-shaped, slightly thicker at the distal part. No accessory glands observed in male pore region. Remarks. Amynthas stabilis sp. nov. is somewhat similar to Amynthas nubilus ( Chen, 1946 ) , Amynthas dactilicus ( Chen, 1946 ) , Amynthas hupeiensis (Michaelsen, 1895) ( Chang et al . 2009 ) and Amynthas dongyinensis Shen, 2014 considering body size, segment number, distance of spermathecal and male pores and intestinal caeca. These species all belong to the sieboldi -group ( Sims & Easton 1972 ). An in-depth comparison table is shown to illustrate more clearly the distinct characters of these four species (Table 3). TABLE ³. A comparison of characters of Amynthas stabilis sp. nov . , A. nubilus ( Chen, 1946 ) , A. dactilicus ( Chen, 1946 ) , A. hupeiensis (Michaelsen, 1895) anđ A. dongyinensis 4hen, 2014. 565 7 character unknown.

Characteristics	Amynthas stabilis sp. nov.	Amynthas nubilus (Chen, 1946)	Amynthas dactilicus (Chen, 1946)	Amynthas hupeiensis (Michaelsen, 1895)	Amynthas dongyinensis 4hen, 2014
Body length (mm)	61 68	7 90	35 70	40 170	49 91
Body width (mm	3.0 3.2	3.0 3.8	2.5 4.0	3.0 5.0	2.8 4.1
Segment number	87 103	107 6	65 108	119 132	91 113
Pigment	tan on miđđle đorsum of the whole bođy, no pigment on ventrum	greyish brown to chocolate on đorsal, purplish on anterior ventrum anđ pale on ventral anđ lateral siđes. Clitellum chocolate brown	pale both đorsally anđ ventrally	đark green on đorsum, light green on ventrum	brown, đark brown on clitellum
’irst dorsal pore	12/13	11/12	4/5	12/13	12/13
Segmental setae number	10 14/III, 17 20/V, 23 26/VIII, 36 38/XX, 32 38/XXV	20 23/III, 6/V, 6/VIII, 6/XX, 36 45/XXV	6/III, 6V, 6/VIII, 6XX, 35/XXV	6/III, 6V, 100-121/VIII, 6 XX, 79-88/XXV	6/III, 6V, 6/VIII, 38 57/XX, 6/XXV
(between male pores	6 8/XVIII	10 14/XVIII	10 12/XVIII	14/XVIII	7 9/XVIII
) between spermathecal pores	6 8/VII, 6/VIII	9 10/VII, 10 11/VIII	17 19/IX	6/VII, 6VIII	38 54/VII, 6/VIII
Spermathecal pores	3 pairs, in 6/7 8/9, 0.33C	3 pairs, in 6/7 8/9, 0.33C	3 pairs, in 6/7 8/9, 0.33C	3 pairs, in 6/7 8/9, 0.25C	3 pairs, in 6/7 8/9, 0.28 0.31C
Preclitellar papillae	4 presetal genital in VIII anđ IX, 0.25C	5 small in VIII ventrally, genital	none	none	none
Male pores	on top of elliptic porophore surrounđeđ by 1 2 circular riđges, 0.33C	on top of porophore, 0.33C	on porophore surrounđeđ by concentric riđges, 0.33C	in center of rounđ papilla, 0.25C	on rounđ porophore surrounđeđ by 1 2 circular or điamonđ-shapeđ folđs, 0.26 0.33C
Postclitellar papillae	4 large intersegmental collapse-toppeđ genital	2 in male pores region, 3 presetal XVII	1 small papilla međially to each male pore, two	large điscs paiređ postsetal in XVII anđ presetal in XIX, 8ust	none
papillae XVII XIX, 0.25C	miđ-ventral, presetal on XVIII	međial to male pores, oval, center concave

……continued on the next page TABLE ³. (Continueđ)

Characteristics	Amynthas stabilis sp. nov.	Amynthas nubilus (Chen, 1946)	Amynthas dactilicus (Chen, 1946)	Amynthas hupeiensis (Michaelsen, 1895)	Amynthas dongyinensis 4hen, 2014
Septa	8/9 9/10 absent	8/9 9/10 absent	8/9 9/10 absent	6	8/9 9/10 absent
Testis sacs	well-đevelopeđ	đevelopeđ	đevelopeđ	đevelopeđ	đevelopeđ
Seminal vesicles	well-đevelopeđ	đevelopeđ	well-đevelopeđ	đevelopeđ	đevelopeđ
Prostate glands	well-đevelopeđ	đevelopeđ	đevelopeđ	đevelopeđ	đevelopeđ
Spermathecae	1.5mm long; ampulla elongate, oval-shapeđ; stout đuct as long as 1/2 ampulla	2.0mm long; ampulla long heart-shapeđ; stout slightly shorter than ampulla	2.0mm long; short stout đuct	ampulla long, rođ-shapeđ; short stout đuct	0.81 1.81mm long; ampulla rounđ, peach-shapeđ or elongateđ oval-shapeđ; short stout đuct
Diverticulum	slightly shorter than main pouch, terminal 1/4 đilateđ into a club-shapeđ seminal chamber	not observeđ	short, seminal chamber đactyloiđ, pointeđ entally	slenđer, longer than twice the length of spermatheca	slightly longer than main pouch, oval- or rođ-shapeđ seminal
Accessory glands	in spermathecal pore region	in spermathecal pore region anđ male pore region	in male pore region	none	in spermathecal pore region

Amynthas stabilis sp. nov. is easily distinguished from Amynthas nubilus ( Chen, 1946 ) and Amynthas dactilicus ( Chen, 1946 ) by its darker body pigment and intersegmental collapse-topped papillae in male pore region. In addition, in Amynthas dactilicus ( Chen, 1946 ) , a spermathecal diverticulum is absent, and there are no preclitellar papillae. Amynthas stabilis is similar to Amynthas hupeiensis (Michaelsen, 1895) with respect to intersegmental collapse-topped papillae in male pore region. However, Amynthas hupeiensis differs from the new species in dark-green body pigment, absence of preclitellar papilla and accessory glands, while its slender spermathecal diverticulum is longer than twice the length of the spermatheca. Amynthas dongyinensis Shen, 2014 differs from the new species in higher setae number (up to 57), absence of papillae near spermathecal pore and male pore, and in the spermathecal diverticulum which is longer than the main pouch.