Amynthas edwardsi Zhao and Qiu, 2009

Zhao, Qi, Sun, Jing & Qiu, Jiang-Ping, 2009, Three new species of the Amynthas hawayanus-group (Oligochaeta: Megascolecidae) from Hainan Island, China, Journal of Natural History 43 (17 - 18), pp. 1027-1041 : 1038-1040

Amynthas edwardsi Zhao and Qiu sp. nov

( Figure 4 )

Type material

Holotype: Clitellate specimen (C-HN007), 53 mm long, 1.8 mm wide, 94 segments. Setae numbers: 26/III, 32/ V, 46/VIII, 32/XX, 38/XXV; 112( VI) between spermathecal pores, 9( XVIII) between male pores, collected in the chocolate-brown soil near the stream of the tropical rain forest in Diaoluoshan National Forest Park , Southeast Hainan (18 ° 439410 N, 109 ° 529370 E), at an altitude of 940 m ( Figure 1 ). Collected by Jiangping Qiu , Bouche , Jianxiong Li and Weixin Zhang . Paratype: one clitellate (C-HN007): same data as for holotype.

Other material

Same data as for holotype, one aclitellate specimen.

Etymology

This species is named after Professor C. Edwards, who is a famous oligochaetist and who has contributed much to earthworm biology.

Diagnosis

Spermathecal pores three pairs, in 5/6–7/8, about one-third of circumference apart, ventrally placed. Male pores a little longer than one-third of circumference apart, ventrally placed, each on top of a pulvinate porophore, smooth on top and surrounded by one or two wrinkles of skin. One pair of flat-topped papillae to the inner side of the male pores anterosetal in XIX.

Description

Worms brown both dorsally and ventrally. Brown on clitellum. Dimensions 53– 56 mm by 1.8–2 mm, segments 94–97. Setae uniformly distributed, their numbers: 25–26 at III, 32–34 at V, 46 at VIII, 32–33 at XX, 38–40 at XXV; 12(VI) between spermathecae, 8–9(XVIII) between male pores; setal formula: AA51.2AB, ZZ51.2– 1.3ZY. Female pore single in the centre of XIV ventrally, ovoid. First dorsal pore in 12/13. Prostomium one-half epilobous. Clitellum in XIV–XVI, ring shaped, markedly glandular, smooth, setae and dorsal pore invisible.

Male pores a little more than one-third of circumference apart, ventrally placed, each on top of a pulvinate porophore, smooth on top and surrounded by one or two wrinkles of skin. One pair of flat-topped papillae to the inner side of the male pores anterosetal in XIX (diameter 0.7–0.8 mm). The distance between them is one-third of circumference apart. Spermathecal pores three pairs, ventral, in 5/6–7/8, about onethird of circumference apart.

Septae 8/9, 9/10 absent; 7/8 comparatively thick; 10/11, 11/12 a little thicker than those following. Gizzard barrel shaped, in IX–X. Intestine swelling in XVI. Intestinal caeca simple, in 1/3XXV–XXVII, smooth on both sides. Hearts three pairs, in XI– XIII, conjoint with supraoesophageal vessel. A pair of circular vessels in X, slender, conjoint with ventral vessel.

Spermathecae three pairs, in VI–VIII, ampulla heart-shaped (0.5–0.7 mm long), duct about four-fifths of ampulla, uniform in calibre, diverticulum is about threequarters of main pouch, with middle in zigzag fashion, the ental one-third clubshaped and enlarged, forming seminal chamber. Testis sacs two pairs, in X, XI, the first pair stouter, the second pair small, silvery white, both separate ventrally. Seminal vesicles two pairs, in XI, XII, the first is stouter. Prostate gland very well developed, in 1/2 XVI–XXIV, finger-shaped lobate, with a U-shaped duct, its ectal limb stouter, the ental limb rather long.

Remarks

Amynthas edwardsi Zhao and Qiu sp. nov also keys to the hawayanus -group in Sims and Easton (1972). It is similar to A. limpidus ( Chen 1938) in having three pairs of spermathecal pores in 5/6–7/8 and by the shape of diverticulum. Nevertheless, it only has one pair of flat-topped papillae to the inner side of the male pores anterosetal in XIX (diameter 0.7–0.8 mm) while three pairs of papillae are positioned ventrally on XVIII–XX in A. limpidus . Compared with the simple and small prostate gland in A. limpidus , A. edwardsi sp. nov has a well-developed prostate gland. Also the second pair of testis sacs does not enclose the first pair of seminal vesicles in A. edwardsi sp. nov. Moreover, A. edwardsi sp. nov is much smaller than A. limpidus , with a length of 53–56 mm. The comparison with other Amynthas species with spermathecal pores in 5/6–7/8 from China is shown in Table 1.

Figures

Figure 1. Collection sites in Hainan Island: species 1, Amynthas bouchei sp.nov. (species 1 was collected in Jianfengling National Nature Reserve); species 2, Amynthas omodeoi sp. nov.; species 3, Amynthas edwardsi sp. nov. (both species 2 and species 3 were collected in Diaoluoshan National Forest Park).

Figure 4. Amynthas edwardsi sp. nov. (A) ventral view. (B) spermathecae; scale bars 1.7 mm (A), 1.0 mm (B).