Amynthas eumorphus Qiu & Zhao, 2018

Zhao, Qi, Yao, Xuanzhu, Lan, Yaqiong, Xu, Junxian & Qiu, Jiangping, 2018, New earthworm species of the genus Amynthas from Hainan Island, China (Megascolecidae, Clitellata), Zootaxa 4496 (1), pp. 279-286 : 283-284

Amynthas eumorphus Qiu & Zhao , sp. nov.

( Figure 3 )

Type material. Holotype. One clitellate specimen (HN201516-02), China, Hainan Province, Longmen Town, the way from Longmen Town to Huangzhu Town (18°40'59"N, 108°51'46"E), 110 m a.s.l., soil, coll. J.P. Qiu, Q. Zhao, J.B. Jiang, L.L. Zhang, Y. Dong, M.S. Chen, 4 June, 2015.

Paratypes. 17 clitellate specimens (HN201516-04), same data as for holotype ; 24 clitellate (HN201511-01), China, Hainan Province, Dongfang City, Nanya Farm (19°26'35"N, 110°21'41"E), 660 m a.s.l., June 2, 2015, other data as for holotype ; 9 clitellate (HN201509-01), China, Hainan Province, Lanyang Town, near the lake of Lanyang Farm (19°30'06"N, 109°41'06"E), 170 m a.s.l., May 31, 2015, other data as for holotype ; 1 clitellate (HN201508-01), China, Hainan Province, Qiongzhong County, near Heaven Village (19°21'49"N, 109°27'27"E), 210 m a.s.l., May 31, 2015, other data as for holotype ; 18 clitellate (HN201503-01), China, Hainan Province, Haikou City, 3303 Feishu Village (19°38'58"N, 110°00'01"E), 90 m a.s.l., May 30, 2015, other data as for holotype .

Locality and habitat. The specimens were collected in the brown, or yellow, or yellow sandy soil under rubber plantation almost all over Hainan province, China.

Etymology. This species is named because of its beautiful appearance.

Diagnosis. Three pairs of spermathecal pores in 6/7–8/9, eye-like, about 0.33 circumferences ventrally apart. Male pores each on a pulvinate protuberance in XVIII, about 0.33 body circumferences apart, surrounded by three skin folds.

Description. Preserved specimens dark brown dorsally, light brown ventrally. Each segment has 2 annuli after IX, dorsal line unclear. Dimensions 221–300 mm by 6.0–8.0 mm at clitellum, segments 100–145; body cylindrical in cross section. Prostomium 1/2 epilobous. Setae multiple, narrowly placed, numbering 26– 38/III, 26– 38/V, 44– 58/VIII, 44–58/XX, 44–60/XXV; 8–10 between male pores; 18–24 (VIII) between spermathecal pores. Setal formula AA=2.0–2.5 AB, ZZ=1.0–1.2 ZY. Clitellum annular XIV–XVI, khaki, smooth, setae invisible. First dorsal pore 6/7. Three pairs of spermathecal pores in 6/7–8/9, ventral, eye-like, about 0.33 body circumferences apart ( Fig. 3A ). Male pores each on a pulvinate protuberance in XVIII, about 0.33 body circumferences apart, surrounded by three skin folds ( Fig. 3B ).

Septa 8/9 thin, 9/10 threadlike, before 8/9 thick and muscular, 10/11 thin, 11/12–12/13 thick. Esophageal hearts in X–XIII. Gizzard in IX–X, ball-shaped. Intestine enlarged distinctly from XV. Intestinal caeca simple, originating in XXVII and extending forward to XXIV, smooth ventrally, several finger-shaped incisions dorsally. Spermathecae paired in VII–IX; ampulla heart-shaped, spermathecal duct half as long as ampulla, diverticulum in VII and IX equal to spermathecal duct, terminal half enlarged as a sharp-pointed seminal chamber ( Fig. 3C ); diverticulum in VIII straight. Male sexual system holandric, testis sacs two pairs in X–XI, developed; seminal vesicles paired in XI–XII, developed. Prostates in XVI–XVIII, developed, coarsely lobate, prostatic duct U-shaped in 1/2XVII–1/2XVIII ( Fig. 3D ).

Remarks. Amynthas eumorphus sp. nov. keys to the sieboldi -group according to Sims & Easton (1972). Among all the species in the same group, including 51 species in China and Southeast Asia ( Beddard, 1912; Chen 1930, 1931, 1933, 1936, 1946; Cognetti 1908; Gates 1930, 1932, 1933, 1935; Goto & Hatai 1989; Hatai 1930; Michaelsen 1895, 1896, 1900, 1907, 1922, 1923, 1924, 1928, 1931, 1934; Ohfuchi 1951, 1956; Qiu 1992; Qiu et al. 1993; Rosa 1890, 1892, 1896, 1901; Tsai 1964), A. eumorphus sp. nov. is most similar to Amynthas daulis fanjinmontis ( Qiu 1992) . Both of them have the first dorsal pore before 10/11 and simple intestinal caeca. The shape of spermathecae and diverticulum of them are also much the same. However, they have distinct differences in body length, position of the first dorsal pore, genital papillae, septa in 8/9–9/10 and accessory glands. A. eumorphus sp. nov. is a large species with a length of 221–300 mm compared to the small individuals of A. daulis fanjinmontis with only 34–44 mm body length. The first dorsal pore in A. daulis fanjinmontis is in 3/4 or 4/5 while it is positioned in 6/ 7 in the new species. There are no genital markings or papillae nor accessory glands in A. eumorphus sp. nov. The septa in 8/9–9/10 of A. daulis fanjinmontis are absent while they are membrane-like in the new species. As a result, we decided to give new species status to our specimens.

Figures

FIGURE 3. Amynthas eumorphus sp. nov. A. Ventral body surface with spermathecal pores. B. Ventral body surface with male pores. C. Spermatheca. D. Prostate.