Amynthas hongyehensis Tsai and Shen, 2010

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 : 2277-2280

Amynthas hongyehensis Tsai and Shen, 2010

( Figure 4)

Amynthas hongyehensis Tsai, Shen and Tsai 2010, p. 1263 .

Material examined

Holotype (TESRI-O-H-34) and paratype (TESRI-O-P-29) 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; one clitellate (dissected) collected 16 March 2000 along the Yenping Forest Road (elevation 1000 m) near Hongyeh, Taitung County by the same collectors as for the holotype (coll. no. 2000-27-Shen); one aclitellate collected 16 September 2005 at Tuban Village (elevation 390 m), Dajen, Taitung County by H.P. Chen, I.M. Hsiao and S. T. Chang (coll. no. 2005-40) (voucher number: TBM1); three clitellates [one dissected (voucher number: East 38)] and 20 aclitellates collected 13 July 2010 from Coastal Mountains Cycas taitungensis Nature Reserve (elevation 490 m), Taitung County by H.P. Chen and C.I. Chang (coll. no. 2010-40) (voucher numbers of specimens used for DNA barcoding analyses: East 36, 38, 39); one clitellate collected 18 October 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. 2010-59); seven 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 81); two clitellates collected 20 October 2010 along the Yenping Forest Road (elevation 1332–1338 m) near Hongyeh, Taitung County by R.C. Jang, M.H. Chen and L.H. Chen (coll. no. 2010-66) (voucher number of specimen used for DNA barcoding analyses: East 101); one clitellate 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); one clitellate 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) (voucher number: East 123); one clitellate [dissected (voucher number: East 134)] collected 24 May 2011 along the Changliang Forest Road (elevation 500 m), Jhuohsi, Hualien County by S. T. Chang, M.H. Chen and C.I. Chang (coll. no. 2011-2); one clitellate (voucher number: East 135) and two aclitellates 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).

Description

External characters. Total length (clitellates) 129–197 mm. Weight 2.64–6.21 g. Segments numbering 85–138. Clitellum XIV– XVI, setae and dorsal pores absent, length 4.32–6.77 mm and width 4.48–7.17 mm. Prostomium epilobous. Three annulets (secondary segments) per segment in VII –XIII. Setal number 46–73 in VII, 59–82 in XX, and 10–18 between male pores in XVIII. First dorsal pore in 11 / 12. Spermathecal pores three or four pairs, small, buried deeply in intersegmental furrows of 6 / 7–8 / 9 or 5 / 6–8 / 9 ( Figure 4A), distance between paired pores 0.24–0.29 body circumference ventrally apart. Genital papillae absent in the preclitellar region. Female pore single, mid-ventral in XIV.

Male pores paired in XVIII, 0.22–0.29 body circumference ventrally apart. Each pore on a round, white porophore 0.55–0.8 mm in diameter, surrounded by one to three shallow skin folds. Genital papillae large, round, usually two pairs located slightly medially to the porophore in presetal XVIII and XIX, and an additional pair in XX for paratype ( Figure 4B), occasionally one pair only in presetal XVIII or XIX ( Figure 4C), or two pairs in XVIII with one pair antero-medial and the other postero-medial to male porophores ( Figure 4D), or two pairs in XVIII together with one pair in presetal XIX. Each papilla 0.45–0.98 mm in diameter with depressed centre .

Preserved specimens purple brown on head and dorsum, light brown on ventrum, and darkish purple brown around clitellum. Setal ring white, distinctive.

Internal characters. Septa 5 / 6–7 / 8 and 10 / 11 thick, 11 / 12–13 / 14 muscular. Nephridial tufts thick on anterior faces of 5 / 6 / 7. Gizzard in VIII –X, large, yellowish in colour. Intestine enlarged from XVI. Intestinal caeca paired in XXVII, extending anteriorly to XXII–XXIV, each simple, slender, slightly wrinkled. Oesophageal hearts in XI–XIII.

Spermathecae three pairs in VII –IX or four pairs in VI –IX, ampulla large, oval or peach-shaped, surface wrinkled, each 1.38–3.91 mm long and 1.4–2.54 mm wide, with a short, stout spermathecal stalk 0.35–0.57 mm in length. Diverticulum with an oval-shaped seminal chamber 0.7–1.1 mm long and a slender stalk 0.81–1.65 mm in length ( Figure 4E).

Holandry: testes large, two pairs in ventrally joined sacs in X and XI. Vas efferens connected in XII on each side to form a vas deferens. Seminal vesicles two pairs in XI and XII, large, occupying the full compartment, usually anterior pair larger, each vesicle with a round, finely folliculated dorsal lobe, darker in colour. Prostate glands large, lobed, folliculated, in XVI – XIX, XVI –XX, or XVII –XX. Prostatic duct long, U-shaped in XVII – XVIII. Accessory glands sessile, each oval-shaped, 0.55–0.75 mm long, corresponding to its external genital papilla ( Figure 4F).

DNA barcodes

GenBank accession numbers JX290399 , JX290419 , JX290421 , JX290422 , JX290427 , JX290400 , JX290406 , JX290410 and JX290411 (TBM1, East 36, 38, 39, 81, 101, 123, 134 and 135, respectively) .

Remarks

Amynthas hongyehensis is found at elevations of 250–1350 m on the east slope of the Central Mountain Range, with Changliang Forest Road in southern Hualien to the north and Tuban in southern Taitung to the south of its distribution range according to the current information on field collections. The type locality, Yenping Forest Road near Hongyeh Village , Taitung, is approximately located in the central part of the above-mentioned range. All specimens from the type locality are sexthecate with spermathecal pores in intersegmental furrows of 6 / 7–8 / 9, whereas those collected from other localities are octothecate. It seems that reduction in the numbers of spermathecae might not be uncommon among the native Taiwanese earthworms as discussed in the Remarks of A. amplipapillatus .