Amynthas dongfangensis Qiu & Sun

Sun, Jing, Zhao, Qi & Qiu, Jiang-Ping, 2010, Three new species of earthworms belonging to the genus Amynthas (Oligochaeta: Megascolecidae) from Hainan Island, China, Zootaxa 2680, pp. 26-32 : 30

Amynthas dongfangensis Qiu & Sun sp. nov.

( Figs. 3 A, B)

Material. Holotype: One clitellate (C-HN010): China, Hainan Province, Mt. Jianfeng (18°44.36’N, 108°50.40’E), 980 m. elevation, coll. J. P. Qiu and J. X. Li, 5 Jun, 2006.

Locality and habitat. The specimen was collected from yellow cinnamon soil under montane forest composed of Chinese fan-palm trees and camphor trees of Jianfeng Mountain, Dongfang country, Hainan province, China.

Etymology. The species is named after its location.

Diagnosis. Dimensions 44mm by 1.5mm at clitellum, incomplete posterior amputee. Setae 28/III, 26/V, 34/VIII, 34/XX, 36/XXV; 5 between male pores; 10 between spermathecal pores. Spermathecal pores in 4/5– 8/9, about 0.33 circumference ventrally apart. Male pores paired in XVIII, 0.33 body circumference ventrally apart, each on the centre of flat-topped conical protuberance surrounded by three to five circular folds.

Description. Preserved specimens dark brown or purple on dorsum in front of clitellum, brown on dorsum behind clitellum, lacking pigment on ventrum. Dimensions 44mm by 1.5mm at clitellum, incomplete posterior amputee; body cylindrical in cross-section, gradually tapered towards head. No secondary annulations in front of clitellum. Prostomium ½epilobous. Setae numbering 28 at III, 26 at V, 34 at VIII, 34 at XX, 36 at XXV; 5 between male pores; 10 between spermathecal pores, setal formula: AA=1.2AB, ZZ=2ZY. Clitellum annular XIV–XVI, relatively long, smooth, swollen, reddish-brown, setae invisible externally.

First dorsal pore 11/12. Five pairs of spermathecal pores in 4/5–8/9, ventral, eye-like, small, about 0.33 circumference ventrally apart. Male pores paired in XVIII, 0.33 body circumference ventrally apart, each on the centre of flat-topped conical protuberance surrounded by three to five circular folds ( Fig. 3 A). Female pore on XIV, in a small ovoid tubercle. Genital markings not present.

Septa 6/7 thick, 8/9–9/10 absent. Dorsal blood vessel single, continuous onto pharynx; esophageal hearts in X–XIII. Gizzard in VIII–X, long bucket-shaped; intestine enlarged distinctly from XV; intestinal caeca simple and smooth, originating in XXVII and extending forward to XXV.

Ovaries in XIII, spermathecae paired in V–IX; ampulla oval-shaped and fully filled, 1.1mm long, with an equal duct; diverticulum longer than 0.25 length of main pouch, terminal 0.33 dilated into a pointed cayenneshaped chamber; no nephridia on spermathecal ducts ( Fig. 3 B). Male sexual system holandric, testis sacs two pairs, in X–XI, first pair developed, oval-shaped, the latter pair possibly incorporating seminal vesicles; seminal vesicles paired in each of XI and XII, well developed; prostates in XVII–XXI, gland developed, racemose, prostatic duct n-shaped.

Remarks. The present species keys to the hexathecus group which comprises ten species ( Sims & Easton, 1972). They were collected from Borneo, the Philippines, or the Solomon Islands. These ten reported species are distinguished by the presence or absence of septa in 8/9–9/10, the relationship between the first pair of seminal vesicles and the second pair of testis sacs including whether they are enclosed or unenclosed, the shapes of spermathecae and diverticulum and the variety of male pore region papilla. The common characteristics are that they have five spermathecal pores in 4/5–8/9 and developed prostate glands. Amynthas dongfangensis sp. nov. is similar to A. orientalis ( Beddard, 1912) except with regards to the absence or presence of septa in 9/10, they are quite different. In addition, the shape and the length of diverticulum of A. orientalis is club-shaped and one-half the length of the spermatheca, while that of Amynthas dongfangensis sp. nov. is cayenne-shaped and one and a quarter the length of the spermatheca. What is more, the clitellum of A. orientalis is in 2/3XIV–1/3XVI, the first dorsal pores are in 12/13, and its last pair of hearts is in segment XII, however the clitellum of Amynthas dongfangensis sp. nov. is in XIV–XVI, the first dorsal pores are in 11/ 12, and its last pair of hearts is in segment XIII. Finally, large genital papillae are present in A. orientalis , but not in Amynthas dongfangensis sp. nov. The cecum location of A. orientalis was not record by Beddard, some information available suggests that this species may be a Pithemera , but this has not been confirmed. Anyway, Sims & Easton (1972) regarded this species as a Amynthas , for this reason, we distinguish the new species from this one.

Figures

FIGURE 3. (A) Ventral view showing spermathecal pores, female pores and male pores of Amynthas dongfangensis sp. nov.; (B) spermatheca of Amynthas dongfangensis sp. nov.