Amynthas amis Shen, 2012

Shen, Huei-Ping, 2012, Three new earthworms of the genus Amynthas (Megascolecidae: Oligochaeta) from eastern Taiwan with redescription of Amynthas hongyehensis Tsai and Shen, 2010, Journal of Natural History 46 (37 - 38), pp. 2259-2283 : 2261-2267

Amynthas amis Shen , sp. nov.

( Figure 1 )

Type material

Holotype. Clitellate (mature) specimen (94 mm in length, dissected) collected 24 May 2011 along the Changliang Forest Road (elevation 650–700 m), Jhuohsi , Hualien County by S. T. Chang, M.H. Chen and C.I. Chang (TESRI-O-H-35) (voucher number: East 131).

Paratypes. Two clitellates [one dissected (voucher number: East 96)] collected 20 October 2010 along the Yenping Forest Road (elevation 1470 m) near Hongyeh , Taitung County by R. C. Jang, M.H. Chen and L.H. Chen (TESRI-O-P-30) .

Other material

Twenty-five clitellates and three aclitellates collected 16 March 2000 along Road 20 near Wulu (elevation 713 m), Taitung County by C.F. Tsai, S.C. Tsai, H.P. Shen, S.T. Chang, H.S. Fang, H.P. Yang, and T.J. Lin (coll. no. 2000-24); 29 clitellates and three aclitellates collected 16 March 2000 along Road 20 near Hsinwu (elevation 412 m), Taitung County by C.F. Tsai, S.C. Tsai, H.P. Shen, S.T. Chang, H.S. Fang, H.P. Yang, and T.J. Lin (coll. no. 2000-25); 17 clitellates and an aclitellate collected 16 March 2000 along the Yenping Forest Road (elevation 1000 m) near Hongyeh Village, Taitung County by C.F. Tsai, S.C. Tsai, H.P. Shen, S.T. Chang, H.S. Fang, H.P. Yang, and T.J. Lin (coll. no. 2000-27); nine clitellates and three aclitellates collected 16 March 2000 along the Yenping Forest Road (elevation 950 m) near Hongyeh Village, Taitung County by C.F. Tsai, S.C. Tsai, H.P. Shen, S.T. Chang, H.S. Fang, H.P. Yang, and T.J. Lin (coll. no. 2000-28); one clitellate collected 15 September 2005 along Road 20 near Wulu (elevation 713 m), Taitung County by H.P. Chen, I.M. Hsiao and S.T. Chang (coll. no. 2005-34) (voucher number: EWL1); two clitellates collected 13 April 2010 from Coastal Mountains Cycas taitungensis Nature Reserve (elevation 490 m), Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-6); one clitellate collected 13 April 2010 from the bank of Bieh Creek (elevation 405 m) in Fongnan Village, Fuli, Hualien County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-7); two clitellates collected 13 April 2010 from a ditch along a small slope (elevation 496 m) in Fongnan Village, Fuli, Hualien County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-8); two clitellates collected 14 April 2010 along the Hsirung Forest Road (elevation 767 m), Dongho, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-10); two clitellates collected 14 April 2010 along the Hsirung Forest Road (elevation 613 m), Dongho, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-11); one clitellate collected 12 July 2010 near Gaotai (elevation 245 m), Chenggung, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2010-33); eight clitellates [one dissected (voucher number: East 30)] collected 13 July 2010 from Chihkoshan (elevation 609 m), Yuli, Hualien County by H.P. Chen and C.I. Chang (coll. no. 2010-36) (voucher numbers of specimens used for DNA barcoding analyses: East 27, 29, 30); one clitellate collected 13 July 2010 from Chihkoshan (elevation 846 m), Yuli, Hualien County by H.P. Chen and C.I. Chang (coll. no. 2010- 37); two clitellates and two aclitellates collected 13 July 2010 from Coastal Mountains Cycas taitungensis Nature Reserve (elevation 515 m), Taitung County by H.P. Chen and C.I. Chang (coll. no. 2010-39); one clitellate and an aclitellate collected 15 July 2010 along the Hsirung Forest Road (elevation 767 m), Dongho, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2010-45); two clitellates and an aclitellate collected 15 July 2010 along the Hsirung Forest Road (elevation 613 m), Dongho, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2010-47); two clitellates collected 19 October 2010 along the Hongshih Forest Road (elevation 1280–1354 m) near Guanshan, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010- 60) (voucher number of specimen used for DNA barcoding analyses: East 71); five clitellates collected 19 October 2010 along the Hongshih Forest Road (elevation 1232 m) near Guanshan, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-61); five clitellates collected 19 October 2010 along the Hongshih Forest Road (elevation 1023 m) near Guanshan, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-62); 10 clitellates and an aclitellate collected 19 October 2010 along the Hongshih Forest Road (elevation 750 m) near Guanshan, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-63) (voucher numbers of specimens used for DNA barcoding analyses: East 86, 87); 14 clitellates (one dissected) collected 20 October 2010 along the Yenping Forest Road (elevation 1470 m) near Hongyeh, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-65); five clitellates and an aclitellate collected 20 October 2010 along the Yenping Forest Road (elevation 1335 m) near Hongyeh, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-66); 10 clitellates collected 20 October 2010 along the Yenping Forest Road (elevation 1170–1274 m) near Hongyeh, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-67) (voucher numbers of specimens used for DNA barcoding analyses: East 105, 107, 108); seven clitellates and an aclitellate collected 20 October 2010 along the Yenping Forest Road (elevation 871–942 m) near Hongyeh, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-68); 10 clitellates and two aclitellates collected 20 October 2010 along the Yenping Forest Road (elevation 754 m) near Hongyeh, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-69); one semi-clitellate collected 20 October 2010 along the Yenping Forest Road (elevation 453–507 m) near Hongyeh, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-70) (voucher number: East 126); six clitellates collected 24 May 2011 along the Changliang Forest Road (elevation 647–707 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-1) (voucher number of specimen used for DNA barcoding analyses: East 130); two clitellates and one aclitellate collected 24 May 2011 along the Changliang Forest Road (elevation 250 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-3); six clitellates collected 25 May 2011 along Jungping Forest Road (elevation 1170 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-5); one clitellate collected 25 May 2011 along Jungping Forest Road (elevation 1150 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-6); five clitellates collected 25 May 2011 along Jungping Forest Road (elevation 780–851 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-7); one clitellate collected 26 May 2011 along the Walami Trail (elevation 500–600 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-10); one clitellate collected 8 June 2011 along Rueisuei Forest Road (elevation 1370–1400 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-14) (voucher number: East 178); one clitellate [dissected (voucher number: East 180)] collected 8 June 2011 along Rueisuei Forest Road (elevation 1042 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-16); one clitellate collected 8 June 2011 along Rueisuei Forest Road (elevation 575 m), Jhuohsi, Hualien County by S.T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-17); one clitellate collected 26 July 2011 along Hsilin Forest Road (elevation 976–1017 m), Wanrung, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-40); one clitellate collected 26 July 2011 along Hsilin Forest Road (elevation 760–807 m), Wanrung, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-42); one clitellate collected 27 July 2011 along Wanrung Forest Road (elevation 590 m), Wanrung, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-47); two clitellates collected 27 July 2011 along Wanrung Forest Road (elevation 515 m), Wanrung, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-49); one clitellate collected 27 July 2011 along Wanrung Forest Road (elevation 510m), Wanrung, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-50) (voucher number: East 276); two clitellates collected 28 July 2011 along Guangfu Forest Road (elevation 1121–1177 m), Wanrung, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-52) (voucher number of specimen used for DNA barcoding analyses: East 278); one clitellate collected 28 July 2011 along Guangfu Forest Road (elevation 1085–1106 m), Wanrung, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-53); 28 clitellates collected 28 July 2011 along Guangfu Forest Road (elevation 510–540 m), Guangfu, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-56) (voucher numbers of specimens used for DNA barcoding analyses: East 277, 279, 280); one clitellate collected 23 August 2011 along Baibaohsi Agricultural Road (elevation 540 m), Shoufong, Hualien County by M.H. Chen and C.I. Chang (coll. no. 2011-59) (voucher number: East 282); seven clitellates collected 25 October 2011 along Lijia Forest Road (elevation 920 m), Beinan, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2011-87) (voucher numbers of specimens used for DNA barcoding analyses: East 281, 283, 284, 286); three clitellates collected 25 October 2011 along Lijia Forest Road (elevation 1344–1386 m), Beinan, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2011-88) (voucher numbers of specimens used for DNA barcoding analyses: East 285, 288); six clitellates collected 25 October 2011 along Lijia Forest Road (elevation 1283–1349 m), Beinan, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2011-89) (voucher numbers of specimens used for DNA barcoding analyses: East 287, 291); one clitellate collected 25 October 2011 along Lijia Forest Road (elevation 1212 m), Beinan, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2011-90); three clitellates collected 25 October 2011 along Lijia Forest Road (elevation 1083 m), Beinan, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2011-91); 22 clitellates collected 25 October 2011 along Lijia Forest Road (elevation 1042–1081 m), Beinan, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2011- 92) (voucher numbers of specimens used for DNA barcoding analyses: East 289, 290); one clitellate collected 26 October 2011 near Nanhsi (elevation 620 m), Changbin, Taitung County by H.P. Chen and C.I. Chang (coll. no. 2011-94) (voucher number: East 292).

Diagnosis

Small to medium; length (clitellates) 53–183 mm. Segments numbering 77–115. Setae 28–42 in VII, 40–48 in XX, 8–12 between male pores. First dorsal pore in 11 / 12 or 10 / 11. Spermathecal pores four pairs in 5 / 6–8 / 9, 0.25–0.32 body circumference ventrally apart. Male pores 0.23–0.27 body circumference ventrally apart in XVIII, each on a round porophore surrounded by three to five circular folds, occasionally with one small papilla antero-medial to it. Genital papillae single median, or closely or widely paired in presetal VII–IX, immediately adjacent to intersegmental furrows. Spermathecae four pairs in VI–IX. Seminal vesicles large, two pairs in XI and XII. Prostate glands large, occupying three to five segments in XVI–XX. Prostatic duct long, C-shaped or U-shaped. Accessory glands short-stalked in the preclitellar region and sessile in the postclitellar region, each corresponding to external genital papilla.

Description

External characters. Total length (clitellates) 53–183 mm. Weight 0.23–2.8 g. Segments numbering 77–115. Clitellum XIV–XVI, length 1.49–4.54 mm and width 2.83–5.37 mm. Prostomium epilobous. Setal number 28–42 in VII, 40–48 in XX and 8–12 between male pores in XVIII. First dorsal pore in 11 / 12 or 10 / 11. Spermathecal pores four pairs in intersegmental furrows of 5 / 6–8 / 9, distance between paired pores 0.25–0.32 body circumference ventrally apart. Genital papillae round, variable in number, position and arrangement. Presetal papillae single median ( Figure 1A ), closely paired ( Figure 1B ) or widely paired ( Figure 1C ) in VII–IX, occasionally also in X, immediately adjacent to intersegmental furrows. Each papilla 0.3–0.7 mm in diameter, with or without a concave centre. No preclitellar papilla in the postsetal portion and in the vicinity of spermathecal pores. Female pore single, mid-ventral in XIV.

Male pores paired in XVIII, 0.23–0.27 body circumference ventrally apart. Each pore on a round porophore surrounded by three to five circular folds ( Figure 1D ), occasionally with one small papilla about 0.25 mm in diameter antero-medial to it ( Figure 1E ). No other papilla in the postclitellar region.

Preserved specimens brown to dark brown on dorsum, light brown on ventrum, and light orange brown to dark brown on clitellum.

Internal characters. Septa 5 / 6–7 / 8 and 10 / 11–13 / 14 thick, 8 / 9 / 10 missing. Nephridial tufts thick on anterior faces of 5 / 6 / 7. Gizzard large, round in VIII–X. Intestine enlarged from XVI. Intestinal caeca paired in XXVII, extending anteriorly to XXIII– XXIV, each simple, slender, straight or slightly bent at distal end. Oesophageal hearts in XI–XIII.

Spermathecae four pairs in VI–IX, varied in sizes and shapes ( Figure 1F ). Each ampulla round or elongated oval-shaped, surface wrinkled, 0.68–3.1 mm long and 0.45–1.82 mm wide, with a slender to stout spermathecal stalk of 0.15–0.8 mm in length. Diverticulum with an iridescent, oval-shaped seminal chamber of 0.15–0.8 mm long and a slender stalk of 0.3–1.2 mm in length. Accessory glands short-stalked, round or slightly lobed, 0.45–0.85 mm in total length, corresponding to external genital papillae ( Figure 1F ).

Holandry: testes large, oval, two pairs in ventrally joined sacs in X and XI. Seminal vesicles large, smooth, two pairs in XI and XII, occupying the full segmental compartment or one and a half segments, with a round dorsal lobe. Prostate glands large, lobed with follicular surface, occupying three to five segments in XVI– XX ( Figure 1G ). Prostatic duct long, C-shaped in XVIII or U-shaped in XVII–XVIII, distal end enlarged. Accessory gland sessile, round, corresponding to external genital papilla antero-medial to the male pore if present.

DNA barcodes

GenBank accession numbers JX290445 (East 131, holotype), JX290430 (East 96, dissected paratype), JX290398 , JX290415 , JX290416 , JX290417 , JX290425 , JX290428 , JX290429 , JX290401 , JX290403 , JX290404 , JX290407 , JX290408 , JX290413 , JX290414 , JX290381 , JX290382 , JX290384 , JX290385 , JX290386 , JX290387 , JX290383 , JX290388 , JX290389 , JX290390 , JX290391 , JX290392 , JX290393 , JX290394 , JX290395 , JX290396 and JX290397 (EWL1, East 27, 29, 30, 71, 86, 87, 105, 107, 108, 126, 130, 178, 180, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291 and 292, respectively) .

Etymology

The species name “ amis ” is given because most of the distribution range of this species overlaps with areas inhabited by the native Amis Tribe living in the East Rift Valley and Pacific Coastal Plain east of the Central Mountain Range.

Remarks

Amynthas amis sp. nov. is an octothecate earthworm belonging to the diffringens (= corticis ) species-group of the genus Amynthas ( Sims and Easton 1972) . It is widely distributed at elevations of 245–1500 m south of Mugua River in eastern Taiwan. The genital papillar arrangement of widely paired papillae in presetal VII–IX for some individuals and simple male pore structure with or without an antero-medial papilla are fairly similar to that of Amynthas corticis (Kinberg, 1867) , Amynthas divergens divergens (Michaelsen, 1892) from Japan, Amynthas divergens yunnanensis ( Stephenson, 1912) from Yunnan, China, Amynthas nipponicus ( Beddard, 1892) and Amynthas oyamai ( Ohfuchi, 1937) from Japan, and Amynthas morii (Kobayashi, 1938) from Korea. These six species are also members of the corticis species-group. All of them have small or less developed seminal vesicles. Considerable variations in the structure and size of spermathecae and prostate glands were found for A. divergens ( Ohfuchi 1937) , considerable variations in the size and shape of spermathecae were reported for A. nipponicus ( Ohfuchi 1937) , prostate gland absent or poorly developed was recorded for A. oyamai ( Ohfuchi 1937; Kobayashi 1938a), and prostate gland absent in most specimens was found for A. corticis ( Chen 1931, 1933), A. nipponicus ( Ohfuchi 1937) and A. morii ( Kobayashi 1938b) . The single specimen of A. divergens yunnanensis has no prostate glands either ( Stephenson 1912). In contrast to the reproductive organ degeneration in these species, A. amis has large seminal vesicles and prostate glands, and iridescence on all four pairs of its spermathecae. Unlike the widely spread A. corticis , A. amis is only found in eastern Taiwan. Easton (1981) considered that A. divergens , A. nipponicus and A. oyamai are synonyms of A. corticis . Though their papillar arrangements look similar, there are distinct differences among these species ( Table 1).

The simple male pore structure of A. amis is also similar to that of Amynthas toriii ( Ohfuchi, 1941) from Japan. Amynthas toriii is much smaller (37–43 mm in length), has no genital papillae, and has higher setal number than A. amis with 43–45 in VIII and 56–58 in XX and slender, straight prostatic ducts ( Ohfuchi 1941). Therefore, the two species can be easily distinguished. Amynthas toriii was also placed in synonymy of A. corticis in Easton (1981). It certainly is a valid species as discussed in Tsai et al. (2007).

Figures

Figure 1. Amynthas amis sp. nov. (A) Ventral view of spermathecal pore region of the dissected paratype (TESRI-O-P-30) (voucher number: East 96) (gp, genital papilla; sp, spermathecal pore); (B) ventral view of spermathecal pore region of holotype (TESRI-O-H-35) (voucher number: East 131); (C) ventral view of spermathecal pore region of a 84-mm clitellate [dissected (voucher number: East 180), coll. no. 2011-16]; (D) ventral view of male pore region of holotype (mp, male porophore); (E) ventral view of male pore region of a 54-mm clitellate [dissected (voucher number: East 30), coll. no. 2010-36]; (F) dorsal view of left spermathecae of the dissected paratype (amp, ampulla; dv, diverticulum; ag, accessory gland); (G) dorsal view of left prostate gland of the dissected paratype. Scale bar 1 mm.