Amynthas kaopingensis, James & Shih & Chang, 2005

James, Samuel W., Shih, Hsi-Te & Chang, Hsueh-Wen, 2005, Seven new species of Amynthas (Clitellata: Megascolecidae) and new earthworm records from Taiwan, Journal of Natural History 39 (14), pp. 1007-1028 : 1017-1020

Amynthas kaopingensis sp. nov.

( Figure 3A, B )

Holotype: adult collected at Caopu , Shihzih, Pingtung County, Taiwan, 17 November 1996, by Gao-Shih Hsiang, NMNS 4054-014 .

Other material. One adult, Caopu, Shihzih, Pingtung County, Taiwan, 8 August 1998, Chang-Yi Tsai coll., NMNS 4054-015 . Three adults, Dahanshan (5 Mt. Dahan), Pingtung County, Taiwan, 22 ° 249480N, 22 ° 249480E; 61 m, 21 February 2000, H.- T. Shih coll., NMNS 4054-016 . Five adults, Taiwu, Pingtung County, Taiwan, 29 January 2000, Chi-Pin Wu coll., NMNS 4054-017 . One adult, Dahanshan, Pingtung County, Taiwan, 22 ° 249520E, 120 ° 399460E; 665 m, 22 February 2000, H.- T. Shih coll., NMNS 4054-018 . One adult, Meinong, Kaohsiung County, Taiwan, 8 March 1999, Chao-Shen Chen coll., NMNS 4054-019 .

Etymology

This species is named after the combination of prefixes, ‘‘kaoping’’, of its localities, Kaohsiung and Pingtung Counties.

Description

Dimensions 170–300 mm by 10–14 mm at segment x, 8–11mm at xxx, 9–11 mm at clitellum; body cylindrical throughout, segments 160–177. Setae regularly distributed around segmental equators, numbering 130–170 at vii, 126–170 at x, 104–126 at xxv; size uniform; setal formula AA:AB:YZ:ZZ51:1:1:2 at xxv. Female pore single in xiv. Prostomium epilobic, with tongue open. Unpigmented to dorsal brown pigment of variable darkness, first dorsal pore 12/13, 13/14. Clitellum annular xiv–xvi; setae invisible externally.

Male pores minute at posterior end of seminal grooves extending from centre of ovate to rounded angular genital pad longitudinally orientated from 17/18 to equator of xviii, surrounded by epidermal folds, lateral folds closest to male pores enlarged to form flap adjacent to or partially covering genital pad ( Figure 3A ); one specimen with paired oval genital markings presetal xvii slightly median to male pore line; 32–40 setae between male pores, pores 0.32 circumference apart on setal line 22. Spermathecal pores dorsal in 5/6/7/ 8/9, 0.29–0.32 circumference apart dorsally.

Septa 5/6/7/8 thickly muscular, 8/9 membranous, 9/10 absent, 10/11–13/14 thickly muscular; gizzard viii. Intestinal origin 1/2xv; typhlosole simple fold from 27/28, onequarter lumen diameter or smaller. Intestinal caeca simple, margins smooth, xxvii–xxiii; lymph glands from xv, those of xvi very large, acinous. Oesophageal hearts x–xiii, very small links to dorsal vessel xi–xiii; commissural vessels vii, ix lateral, viii to gizzard; supraoesophageal vessel xi–xiv; extraoesophageal vessels join ventral oesophageal wall at 10/11; posterior latero-parietal vessels from body wall of xiv–xvi, septum 13/14 to ventral oesophageal location of extraoesophageal vessels in xiii.

Male sexual system proandric, testes, funnels in ventrally joined sac in x. Seminal vesicles large in xi, with small fine-textured dorsal lobe; seminal vesicles, other contents of xi enclosed in thin sac. Prostates large in xviii, three to five main lobes, each lobe served by two to five small ductlets radiating fan-like from ental end of prostatic duct; ducts stout, straight, muscular, narrowing towards body wall; vasa deferentia join duct at ductglandular portion junction; vasa deferentia non-muscular.

Ovaries in xiii. Paired spermathecae vi–ix; ampulla pear-shaped, duct shorter than ampulla, diverticulum small ovate chamber, stalk slender, either straight or kinked, about same length as duct ( Figure 3B ); no nephridia on spermathecal ducts.

Remarks

Another octothecal proandric species with dorsal intersegmental spermathecal pores, A. kaopingensis is closest to A. hengchunensis in all respects, including details of internal anatomy such as the structure of the ductlets of the prostates, the membrane enclosing segment xi, and the presence of septum 8/9. It differs from A. hengchunensis in the features of the male field, a more dorsal placement of spermathecal pores, and the structure of the spermathecal diverticulum. There seems to be considerable morphological unity among A. kaopingensis , A. hengchunensis and A. formosae .

The male field of A. kaopingensis has seminal grooves, a feature not previously reported in the literature of Taiwan earthworms, but well known among Korean Amynthas ( Kobayashi 1936; Hong and James 2001; Hong et al. 2001) and species from other parts of Asia: A. glabrus ( Gates, 1932) , A. japonicus (Horst, 1883) , A. papilio ( Gates, 1930) , A. plantoporophoratus ( Thai, 1984) , and A. riukiuensis ( Ohfuchi, 1957) . The locations of these species include Myanmar, Japan, Vietnam, and the Ryukyu Islands. The grooves are commonly formed within an otherwise flat genital pad of varying shape, but in A. riukiuensis they are formed by folds on the male field. It is not clear if all are descended from a common ancestral type, or if there could be two or more independent evolutions of seminal grooves in Amynthas . In any case, none of the species with seminal grooves also has copulatory pouches, and therefore these do not belong to Metaphire .

Figures

Figure 3. (A) Left lateral view of segments i–ix and ventral view of Amynthas kaopingensis, with detail of male pore; (B) spermatheca of Amynthas kaopingensis; (C) dorsal view of segments i–x and ventral view of xiv–xix of Amynthas ailiaoensis; (D) left prostate gland of Amynthas ailiaoensis, showing numerous small ductlets (curved line traversing the gland is septum 17/18); (E) spermatheca of Amynthas ailiaoensis; (F) dorsal view of segments i–x and ventral view of xiii–xix, Amynthas chaishanensis (the dashed line on the dorsal view represents the mid-dorsal line); (G) spermatheca of Amynthas chaishanensis.