Amynthas genitalis Qiu & Sun, 2012

Sun, Jing, Jiang, Ji-Bao & Qiu, Jiang-Ping, 2012, Four new species of the Amynthas corticis-group (Oligochaeta: Megascolecidae) from Hainan Island, China, Zootaxa 3458, pp. 149-158 : 155-157

Amynthas genitalis Qiu & Sun , sp. nov.

( Fig. 2C, D)

Material. Holotype: One clitellate (C-HN023-05) specimen, China, Hainan Province, Mt. Diaoluo (18°43.39’N, 109°51.55’E), 930 m. elevation, yellow soil under herbaceous vegetation beside road, 6 Jun. 2006, J. P. Qiu, J. X. Li and M. B. Bouché coll. Paratype: One clitellate (C-HN027-08), China, Hainan Province, Mt. Diaoluo (18°43.39’N, 109°52.34’E), 930 m. elevation, yellow cinnamon soil in bamboo, camphor and beech forest, 6 Jun. 2006, J. P. Qiu and M. B. Bouché coll.

Etymology. This species is named after its genital papillae in the male pore region.

Diagnosis. Medium-sized Amynthas earthworms; four pairs of spermathecal pores in 5/6–8/9, 0.33 circumference ventrally apart; male pores 0.33 body circumference ventrally apart, each on an elliptic glandular elevation without surrounding epidermal wrinkles, with four pairs of ovate and flat-topped genital papillae above setae annulet on XVIII and XIX and below setae annulet on XVII and XVIII; diverticulum longer than main spermathecal axis by 0.4, terminal 0.29 dilated into a rod-shaped chamber.

Description. External characters. Preserved specimens no pigment, unclear mid-dorsal line. Dimensions 83–97mm by 2.3–2.5mm at clitellum, segments 99–109; body cylindrical in cross-section, gradually tapered towards head and tail. Prostomium ½ epilobous. Setae numbering 30–36 at III, 22–26 at V, 32–36 at VIII, 38–46 at XX, 36–56 at XXV; 11–12 between male pores; 8/VI, 8/VII, 8–11/VIII between spermathecal pores, setal formula

AA=1.1AB, ZZ=1.2–1.6ZY. Clitellum annular XIV–XVI, brown; setae can be seen ventrally in XVI; dorsal pores absent within clitellum.

omontis Qiu & Sun, 2009, and A. wulinensis Tsai et al., 2001 .

First dorsal pore 12/13. Four pairs of spermathecal pores in 5/6–8/9, 0.33 circumference ventrally apart. Male pores paired in XVIII, 0.33 body circumference ventrally apart; each on the elliptic, glandular porophore with slightly raised centre, without surrounding epidermal wrinkles. Genital papillae ovate, flat-topped, diameter 0.4–0.5mm, paired above setae annulet on XVIII and XIX; below setae annulet on XVII and XVIII, arranged in longitudinal rows slightly medial to male pores. ( Fig. 2C). Female pore single mid-ventral in XIV.

Internal characters. Septa 6/7–7/8 and 10/11–12/13 slightly thickened, 8/9–9/10 absent. Dorsal blood vessel single, continuous onto pharynx; esophageal hearts enlarged in X–XIII. Gizzard in VIII–X, long bucket-shaped; intestine enlarged gradually from XV; intestinal caeca simple, originating in XXVII and extending forward to XXIV, finger-shaped sac with two indentations on dorsal margin and one indentation on ventral margin.

Ovaries in XIII. Spermathecae paired in VI–IX, about 1.4mm long; ampulla ovoid, small, straight duct as long as 0.6 ampulla; diverticulum longer than main spermathecal axis by 0.4, slender, terminal 0.29 dilated into a rodshaped chamber, bright and white; no nephridia on spermathecal ducts ( Fig. 2D). Male sexual system holandric, testis sacs two pairs, ventral in X, XI, posterior pair bigger in size; seminal vesicles paired in each of XI and XII, separated from each other on ventrum between left and right; prostates in XVII–XX, coarsely lobate with three major lobes, stout muscular duct U-shaped, distal end enlarged. No accessory glands observed.

Remarks. Amynthas genitalis sp. nov. is somewhat similar to Amynthas montanus sp. nov. and Amynthas exiguus aquilonius Tsai et al., 2001 in characters of their male pore region. They belong to the same species group in Sims and Easton (1972). An in-depth comparison table is shown in order to illustrate more clearly the distinct characters of these three species ( Table 3).

The body size of this new species is between Amynthas montanus sp. nov. and Amynthas exiguus aquilonius . The clitellum setae in this new species can be seen ventrally in XVI, but exist in XIV–XVI in Amynthas montanus sp. nov. and are absent in Amynthas exiguus aquilonius . The setae of Amynthas genitalis sp. nov. are fewer than Amynthas montanus sp. nov. The porophore of Amynthas genitalis sp. nov. is clearly smaller than Amynthas exiguus aquilonius . The locality of genital papillae of the three species is not the same as each other, especial in the male pore region. The diverticulum of Amynthas genitalis sp. nov. is longer than the main spermathecal axis compared with a shorter one in Amynthas montanus sp. nov. and Amynthas exiguus aquilonius . Accessory glands were not seen in Amynthas genitalis sp. nov., however, observed in Amynthas exiguus aquilonius .

aquilonius Tsai et al., 2001.