Amynthas leshanensis Sun and Qiu, 2016

Sun, Jing, Jiang, Jibao, Hu, Feng & Qiu, Jiangping, 2016, Four new earthworms of the genus Amynthas (Oligochaeta: Megascolecidae) from Mount Emei, Sichuan Province, China, Journal of Natural History 50, pp. 2499-2513 : 2500-2503

publication ID	https://doi.org/ 10.1080/00222933.2016.1193649
DOI	https://doi.org/10.5281/zenodo.4328446
persistent identifier	https://treatment.plazi.org/id/039B87C9-CA6C-FFA2-28E4-FD7EFE9D39E6
treatment provided by	Carolina
scientific name	Amynthas leshanensis Sun and Qiu
status	sp. nov.

Treatment

Amynthas leshanensis Sun and Qiu sp. nov.

( Figure 1 View Figure 1 (a–d))

Type material

Holotype. One clitellate (C-SC201102-02A) specimen: China, Sichuan Province, Mt. Emei (29°35′29″N, 103°17′12″E), 1300 m elevation, woods and bamboo, in dark cinnamon soil, 27 July 2011, J. Sun, J.B. Jiang, X.D. Lei and H.W. Feng coll. GoogleMaps Paratypes: A total of two specimens, as follows: One clitellate (C-SC201102-02B): Same data as for holotype. One clitellate (C-SC201102-14): Same data as for holotype GoogleMaps .

Etymology

This species was named after the collection location – Leshan City, China.

Diagnosis

Three pairs of spermathecal pores in 6/7–8/9, 0.4 of circumference ventrally apart; each male pore on an elliptical glandular flat-top pad, surrounded by a large irregular shaped pad which extends from 17/18–½ XIX; intestinal caeca complex with three long and broad finger-shaped sacs; spermathecal diverticulum shorter than main spermathecal axis by 0.42, distal 0.5 dilated into elongated ovoid seminal chamber.

Description

External characters. Preserved specimens dark grey on dorsum, lacking pigment on ventrum. Mid-dorsal line pigmented. Dimensions 88–93 mm by 3.0– 3.8 mm at clitellum, segments number 95–120. Body cylindrical in cross section, and gradually tapered towards head and tail. Secondary annulations absent. Prostomium ½ epilobous. First dorsal pore in 11/12. Clitellum annular in XIV–XVI, pale, smooth, swollen, no visible setae externally, and dorsal pore usually absent on clitellum. Setae uniformly distributed, dorsal breaks more distinct than ventral, 22–24 at III, 30–35 at V, 28–36 at VIII, 36–42 at XX, 38–44 at XXV; 10 between male pores; 11–14/VII, 11–14/VIII between spermathecal pores, setal formula AA = 1–1.2AB, ZZ = 2–2.2ZY. Spermathecal pores three pairs in 6/7–8/9, intersegmental, about 0.4 of circumference ventrally apart, with tumid epidermis around each spermathecal pore ( Figure 1 View Figure 1 (a)). Genital papillae absent around spermathecal region. Male pores paired in XVIII, about 0.33 of circumference ventrally apart, each on a small elliptical glandular flat-top pad, swollen, and surrounded by a larger irregular-shaped pad which extends from 17/18–½ XIX. No genital papillae in this region ( Figure 1 View Figure 1 (b)). Female pore single, med-ventral in XIV, elliptical, situated in a depression.

Internal characters. Septa 5/6–7/8 and 10/11–12/13 slightly thickened, 8/9–9/10 absent. Dorsal blood vessel single, continuous onto pharynx; esophageal hearts four

pairs in X–XIII. Gizzard barrel-like, in VIII–X; intestine beginning to swell in XVI; intestinal caeca complex, with three long and broad finger-shaped sacs, originating in XXVII and extending forward to XXIV ( Figure 1 View Figure 1 (c)). Male sexual system is holandric. Testis sacs two pairs, small, ventral in X and XI, connected with membrane on ventrum. Seminal vesicles paired in XI and XII, developed, broadly connected with each other on ventrum; prostate glands developed, coarsely lobate, in ½ XVI–XXI, ducts U-curved, distal end stouter. No visible accessory glands around base of each duct. Female organs: Ovaries in XIII. Spermathecae paired in VII–IX, about 2.6 mm long; ampulla heart-shaped, with very short duct, about 0.6 mm; diverticulum shorter than main spermathecal axis by 0.42, slender, distal 0.5 dilated into elongated ovoid seminal chamber; no nephridia on spermathecal ducts ( Figure 1 View Figure 1 (d)).

Remarks

Amynthas leshanensis sp. nov. keys to the Amynthas sieboldi group according to Sims and Easton, 1972 ( Sims and Easton 1972). Members of this group can be distinguished from those of the other species of the genus Amynthas by three pairs of spermathecal pores intersegmental in 6/7–8/9 and a holandric male sexual system. In many principal respects the present new species is relatively similar to Amynthas obscuritoporus ( Chen, 1930) and Amynthas editus editus ( Chen, 1946) . Moreover, they share the same collection location – Mt. Emei ( Chen 1930, 1946).

The species A. obscuritoporus , which was initially collected in Suzhou City and Nanjing City, Jiangsu Province, China, and subsequently gathered in Wuxi City and Yixing City, Jiangsu Province, Zhejiang Province, Anhui Province and Mt. Emei, Sichuan Province, has several similar characteristics to the new species, as follows: (1) a dark colour on the dorsum and lacking pigment on the ventrum; (2) spermathecal pores three pairs in 6/7– 8/9; (3) spermathecal ampulla heart-shaped with the duct shorter than the ampulla; (4) spermathecal diverticulum is usually about half the length of the main spermathecal axis, and the seminal chamber was described as elongated ovoid or bulb-like; (5) the left and right lobe of testis sacs connected ventro-medially in the form of a transverse band. However, the two are chiefly differentiated from each other as follows: (1) the clitellum of the new species present in XIV–XVI, smooth and swollen, but not present in all cases for A. obscuritoporus ; (2) even though both have the spermathecal pores in 6/7–8/9, the pores of A. obscuritoporus are too small to recognise, comparing with the new species in which the spermathecal pores are surrounded by a relatively large swollen area; (3) the male pores of the new species are surrounded by a larger irregular-shaped pad, while the male pore region of A. obscuritoporus is an obscure whitish patch and appears vague under the skin, or looks like a small crescent-shaped groove in some cases; (4) the intestinal caeca of the new species is complex, while it is simple for A. obscuritoporus ; (5) the prostate glands of the new species are developed, by comparison, but are small or rudimentary in A. obscuritoporus .

Another species, A. editus editus , also collected in Mt. Emei, Sichuan, is somewhat similar to the new species in that they have a similar density of setae, the spermathecal pores are all located in 6/7–8/9, the male pore papillae occupy more than one segment, the spermathecal ampulla is heart-shaped, the seminal chamber is elongated, and the prostate glands are developed with a U-curved duct. However, they differ in the following main characteristics: (1) the pigment of A. editus editus is pale both dorsally and ventrally, but just ventrally for the new species; (2) the first two pairs of spermathecal pores of A. editus editus are extremely close – one seta interval, compared to the last pair – while the distance is equal in the new species; (3) there is a large lens-shaped papilla placed medio-ventrally in the male pore region of A. editus editus but no papillae for the new species; (4) the intestinal caeca is simple for A. editus editus but complex for the new species; (5) the spermathecal diverticulum is very long and the ectal portion of duct coiled in A. editus editus , compared to a shorter and more slender duct in the new species; (6) the first pair of seminal vesicles in XI are enclosed in testis sacs for A. editus editus but are clearly separated for the new species.

Two other recently reported Amynthas sieboldi -group species – Amynthas arenulus Bantaowong and Panha and Amynthas longicaeca Bantaowong and Panha – are somewhat similar to the new species according to the big pad on the male pore region at first glance, and the distance between male pores and spermathecal pores. However, they have many differences. For example: (1) comparing with A. arenulus and A. longicaeca , the new species has a smaller body size; (2) the spermathecal pores have tumid epidermis for the new species, but not for A. arenulus and A. longicaeca ; (3) the intestinal caeca of the new species are complex; however, they are simple for A. arenulus and A. longicaeca ; (4) the duct of spermathecae is stout for A. arenulus , and the diverticulum is very small with ovate knob for A. longicaeca , which are both very different from the new species.

The partial cytochrome c oxidase subunit I ( COI) sequence of the holotype of A . leshanensis sp. nov. has been deposited in the National Center of Biotechnology Information ( NCBI) GenBank with accession number KF205474 View Materials (specimen C-SC 201102 -02A) .