Amynthas tungpuensis Tsai et al., 1999

Shen, Huei-Ping, Chang, Chih-Han & Chih, Wen-Jay, 2016, Four new earthworm species of the genus Amynthas (Megascolecidae: Oligochaeta) from southwestern Taiwan with re-description of Amynthas tungpuensis Tsai, Shen and Tsai, 1999, Journal of Natural History 50 (29 - 30), pp. 1889-1910 : 17-21

Amynthas tungpuensis Tsai et al., 1999

( Figure 6 )

Amynthas tungpuensis Tsai, Shen and Tsai 1999 , p. 34.

Material examined

Holotype (TESRI-O-H-1, coll. no. 1998 – 61) and paratypes (TESRI-O-P-1) collected 2 September 1998 on the mountain slope (elevation 1100 m) behind Tungpu Village, Nantou by C.F. Tsai and K.C. Liaw; three clitellates collected 17 August 2005 on the mountain slope along Nanshan Creek (elevation 780 m), Jenai, Nantou by S.T. Chang, I. M. Hsiao and T.J. Lin (coll. no. 2005 – 3) (voucher numbers: TP1, TP2, TP3); one clitellate collected 13 September 2005 along Meilan Forest Road (elevation 1395 m), Taoyuan, Kaohsiung by H.P. Chen and H.S. Fang (coll. no. 2005 – 19) (voucher number: TP4); one clitellate collected 13 September 2005 along Meilan Forest Road (elevation 1145 m) near Meishan, Taoyuan, Kaohsiung by H.P. Chen and H.S. Fang (coll. no. 2005 – 21) (voucher number: TP5); one clitellate collected 14 September 2005 along Road 20 near Lanya Bridge (elevation 1073 m), Taoyuan, Kaohsiung by H.P. Chen and H.S. Fang (coll. no. 2005 – 24); one clitellate collected 14 September 2005 along Road 20 near Kuaigu (elevation 2472 m), Taoyuan, Kaohsiung by H.P. Chen and H.S. Fang (coll. no. 2005 – 28) (voucher number: TP6); seven clitellates collected 14 September 2005 along Road 20 near Takuanshan-Yako Tunnel (elevation 2737 m) on the borders of Kaohsiung and Taitung by H.P. Chen and H.S. Fang (coll. no. 2005 – 30) (voucher number: TP7); one clitellate collected 13 September 2005 along Road 18 (elevation 2317 m) near the borders of Nantou and Chiayi by Y.P. Fang (coll. no. 2005 – 45) (voucher number: TP8); one clitellate (voucher number: TP9) and an aclitellate (voucher number: TP10) collected 17 July 2007 from roadside slope along Waihu Creek (elevation 230 m) near the borders of Douliou and Linnei, Yunlin by C.H. Chang, T.J. Lin and Y.H. Lin (coll. no. 2007 – 42); eleven clitellates collected 16 August 2007 along Chiatungkeng Creek (elevation 160 – 200 m), Linnei, Yunlin by C.H. Chang, Y.H. Lin and Y.P. Li (coll. no. 2007 – 42); 33 clitellates (voucher number of specimen used for DNA barcoding analyses: TP11) and five aclitellates collected 17 August 2007 along Huangtekeng Creek (elevation 140 – 290 m), Gukeng, Yunlin by C.H. Chang, Y.H. Lin and Y.P. Li (coll. no. 2007 – 69); one clitellate collected 19 March 2008 along Road 18 (elevation 1563 m), Alishan, Chiayi by C.L. Tsai (coll. no. 2008 – 22) (voucher number: TP12); an aclitellate collected 30 September 2009 from the Rueyen Nature Reserve (elevation 2200 m), Nantou by T.J. Lin and K.P. Lo (coll. no. 2009 – 44) (voucher number: TP13); one clitellate collected 1 October 2009 from the Rueyen Nature Reserve (elevation 2225 m), Nantou by T.J. Lin and K.P. Lo (coll. no. 2009 – 45) (voucher number: TP14); an aclitellate collected 25 July 2013 along a hiking trail (elevation 1427 m) near Shihcho, near the borders of Jhuci and Alishan, Chiayi by H.T. Fang (coll. no. 2013 – 1) (voucher number: TP15); two clitellates and an aclitellate collected 25 July 2013 from roadside slopes and ditches around Dinghu (elevation 1661 m), Alishan, Chiayi by H.T. Fang (coll. no. 2013 – 2) (voucher number of specimen used for DNA barcoding analyses: TP16); one semiclitellate (voucher number: TP17) and an aclitellate collected 25 July 2013 along Beitzutong Forest Road (elevation 1541 m) near the borders of Jhuci and Alishan, Chiayi by H.T. Fang (coll. no. 2013 – 3); eight clitellates and two aclitellates collected 25 July 2013 along Fencihu Cedar Wooden Plank Trail (elevation 1418 m), Jhuci, Chiayi by H.T. Fang (coll. no. 2013 – 4) (voucher numbers of specimens used for DNA barcoding analyses: TP18, TP19, TP20); an aclitellate collected 26 July 2013 along a hiking trail in Longyun Farm (elevation 1479 m), Jhuci, Chiayi by H.T. Fang (coll. no. 2013 – 5); one clitellate (voucher number: TP21) and an aclitellate (voucher number: TP22) collected 26 July 2013 from roadside slopes and ditches around Niushan (elevation 1024 m), Guanghua Village, Jhuci, Chiayi by H.T. Fang (coll. no. 2013 – 6); two clitellates collected 16 August 2013 from roadside slopes and ditches around Dinghu (elevation 1662 m), Alishan, Chiayi by H.T. Fang (coll. no. 2013 – 8); one clitellate collected 2 October 2013 along Fencihu Cedar Wooden Plank Trail (elevation 1418 m), Jhuci, Chiayi by H.T. Fang (coll. no. 2013 – 10) (voucher number: TP23); one clitellate [dissected (voucher number: TP24)] collected 6 November 2013 from roadside slopes and ditches around Dinghu (elevation 1662 m), Alishan, Chiayi by H.T. Fang (coll. no. 2013 – 11); two clitellates collected 28 April 2014 from roadside slopes and ditches around Dinghu (elevation 1664 m), Alishan, Chiayi by H.T. Fang (coll. no. 2014 – 1); five clitellates collected 28 April 2014 from roadside ditches around a parking lot at south end of a hiking trail in Longyun Farm (elevation 1486 m), Jhuci, Chiayi by H.T. Fang (coll. no. 2014 – 8) (voucher number of specimen used for DNA barcoding analyses: TP25).

Description

External characters. Total length (clitellates) 63 – 160 mm. Weight 1.08 – 4.37 g. Segments numbering 85 – 128. Clitellum XIV – XVI, setae and dorsal pores absent, length 1.89 – 5.30 mm and width 2.60 – 5.30 mm. Prostomium epilobous. Setal number 35 – 48 in VII, 46 – 59 in XX, and 9 – 16 between male pores in XVIII. First dorsal pore in 11/12, 12/13 or 13/14. Spermathecal pores two pairs in intersegmental furrows of 7/8/9 or three pairs in 6/7 – 8/9 ( Figure 6 a,c), distance between paired pores 0.26 – 0.32 body circumference ventrally apart. Preclitellar genital papillae from absence to two rows arranged transversely and immediately anterior to setal line in VIII and IX, both ends of each row slightly curved anteriorly, number highly variable ( Figure 6 a – c). Each papilla round, 0.25 – 0.31 mm in diameter. Occasionally tiny papillae anterior and/or posterior to each spermathecal pore. Female pore single, mid-ventral in XIV.

Male pores paired in XVIII, 0.26 – 0.30 body circumference ventrally apart. Each pore simple on a round porophore surrounded by three to five circular folds, or with papilla(e) 2013 – 4) (voucher number: TP19). (c) Ventral view of spermathecal pore region of a 113-mm clitellate (coll. no. 2005 – 30) (voucher number: TP7). (d) Ventral view of male pore region of a 155-mm clitellate (coll. no. 2009 – 45) (voucher number: TP14) (mp, male porophore). (e) Ventral view of male pore region of a 113-mm clitellate (coll. no. 2005 – 30) (voucher number: TP7). (f) Ventral view of male pore region of a 153-mm clitellate (coll. no. 2005 – 21) (voucher number: TP5). (g) Ventral view of male pore region of a 157-mm clitellate (coll. no. 2008 – 22) (voucher number: TP12). (h) Ventral view of male pore region of a 69-mm clitellate (dissected, coll. no. 2013 – 11) (voucher number: TP24). (i) Dorsal view of right spermathecae of a 69-mm clitellate (dissected, coll. no. 2013 – 11) (voucher number: TP24) (amp, ampulla; dv, diverticulum; ag, accessory gland). (j) Dorsal view of right prostate gland of a 69-mm clitellate (dissected, coll. no. 2013 – 11) (voucher number: TP24) (pd, prostatic duct). Scale bar 1 mm.

anterior, posteromedial, or one anteromedial and one posteromedial to it ( Figure 6 d – f). Postclitellar genital papillae absent ( Figure 6 d), single-median ( Tsai et al. 1999, p. 34, fig. 1D), one transverse row per segment in mid-ventrum of presetal XVII – XX ( Figure 6 g), or one to four in a row medial to each male porophore in the presetal annulet in XVIII ( Figure 6 h), number and arrangement highly variable. Each papilla round, 0.25 – 0.36 mm in diameter. Occasionally one or two papillae immediately adjacent to intersegmental furrow of 18/19 and medial to each male porophore in presetal XIX.

Live worms dark reddish brown or violet brown. Preserved specimens dark brown or violet brown on dorsum, orange brown or pinkish brown on clitellum, and light or greyish brown on ventrum. Setal lines distinctive, light yellowish white in colour.

Internal characters. Septa 5/6 – 7/8 thick, 10/11 – 13/14 muscular, 8/9/10 absent. Nephridial tufts thick on anterior faces of 5/6/7. Gizzard large, round in VIII – X. Intestine enlarged from XV. Intestinal caeca paired in XXVII, each simple, wrinkled, extending anteriorly to XXI, XXII or XXIII. Oesophageal hearts in XI – XIII.

Spermathecae three pairs in VII – IX or two pairs in VIII and IX, each with a wrinkled, peach-shaped or heart-shaped ampulla 1.30 – 3.05 mm long and 1.60 – 2.53 mm wide, and a short, stout spermathecal stalk 0.25 – 0.50 mm in length. Diverticulum with an iridescent, oval-shaped seminal chamber of 0.65 – 0.75 mm long and a slender stalk of 0.90 – 1.10 mm in length. Accessory glands stalked, 0.57 – 0.83 mm in total length, each corresponding to external genital papilla ( Figure 6 i).

Holandry: testes round, two pairs in ventrally joined sacs in X and XI. Seminal vesicles two pairs in XI and XII, surface folliculated, each vesicle with a round dorsal lobe. Prostate glands racemose, large in XV – XIX, XV – XX or XVI – XIX ( Figure 6 j). Prostatic duct long, U-shaped, proximal half enlarged. Accessory glands stalked, 0.60 – 0.85 mm in total length, each corresponding to external genital papilla ( Figure 6 j).

DNA barcodes

GenBank accession numbers KU232795 – KU232819 (TP1 – 25, respectively).

Remarks

Amynthas tungpuensis is widely distributed throughout north to south Taiwan at elevations of 140 – 2737 m on the western slope of the Central Mountain Range. Its male pore structure and number and arrangement of genital papillae show great intraspecific variation and hence, identification is somewhat difficult based on morphological characters alone. Genetically, this species also has large intraspecific divergence in the DNA barcode region (as large as 12.7% based on Kimura ’ s two-parameter distance) that rivals those previously reported in other Taiwanese Amynthas ( Chang et al. 2007) . Most specimens collected so far are sexthecate with spermathecal pores in intersegmental furrows of 6/7 – 8/9. However, quadrithecate individuals with spermathecal pores in 7/8/9 were found from the Alishan area, Chiayi, southwestern Taiwan. To date among the 56 endemic earthworms reported from the island of Taiwan, 10 of them have variable numbers of spermathecae or even lack spermathecae entirely, suggesting that reduction in the numbers of spermathecae might not be uncommon among the native Taiwanese earthworms as addressed in Shen (2012). Shen et al. (2012) pointed out that the limitation of using number and position of spermathecae as keys to define speciesgroups in pheretimoid earthworms became obvious with the increase of new species found in recent decades.

Since A. tungpuensis is a variable species, Tsai et al. (2009) considered that Amynthas monsoonus James et al. (2005) should be included within its species boundary, and A. monsoonus was therefore regarded as a junior synonym. However, in contrast to their similar external features, A. monsoonus has two pairs of oesophageal hearts in XII – XIII, small prostate glands, sessile genital marking glands ( James et al. 2005) and diverticulum much longer than ampulla ( James et al. 2005, p. 1010, fig. 2D). These characters differ greatly from those of A. tungpuensis . Apparently, A. monsoonus is a valid species. With resurrection of A. monsoonus and the addition of the new species described in this study, the total number of species of terrestrial earthworms from Taiwan and its adjacent islands increases to 104.

Figures

Figure 6. Amynthas tungpuensis Tsai, Shen and Tsai, 1999. (a) Ventral view of spermathecal pore region of a 77 - mm clitellate (coll. no. 2013 – 4) (voucher number: TP 20) (gp, genital papilla; sp, spermathecal pore). (b) Ventral view of spermathecal pore region of a 76 - mm clitellate (coll. no.