Amynthas dabudongensis, Hong & James, 2009

Hong, Yong & James, Samuel W., 2009, Some new Korean Megascolecoid earthworms (Oligochaeta), Journal of Natural History 43 (21 - 22), pp. 1229-1256 : 1233-1234

Amynthas dabudongensis sp. nov.

( Figure 3 )

Type material

Holotype: Clitellate (NIBRIV0000120464) specimen: Korea, Gyeongsangbuk-do, Chilgok-gun, Dabudong , 18 August 1971, G.S. Kim coll. 1 paratype: 1 clitellate (NIBRIV0000120476): Same data as for holotype.

Other material

Same data as for holotype, 7 clitellate specimens.

Etymology

The species is named after its type locality.

Diagnosis

Spermathecal pores in 5/6/7, spots on conspicuous bumps, 0.27–0.32 mm circumference apart; male pores on circular elevated porophores, 0.20–0.30 mm circumference apart; two 0.2-mm circular genital papillae on each porophore.

Description

Brown dorsal pigment. Dimensions 74–98 by 4.0– 4.7 mm at segment X, 4.1–4.8 mm at XXX, 4.0– 5.3 mm at clitellum; body cylindrical throughout, segments 57–87. Setae regularly distributed around segmental equators, numbering 50 at VII, 52 at XX; 13–19 between male pores, size and distance regular; setal formula AA: AB: YZ: ZZ = 4: 2: 2: 4.5 at XIII. Female pore single in XIV, 0.3 mm, oval-shaped. First dorsal pore 12/13.

Male pores on circular elevated porophores; each porophore with small longitudinally placed rectangular indentation at centre of which is male pore, 0.20–0.30 mm circumference apart. Two 0.2-mm circular genital papillae on each porophore, one adjacent to male pore laterally, one slightly removed medially. Spermathecal pores in 5/6, 6/7, obvious bright bumps, spots on conspicuous bumps, spermathecal pores 0.27–0.32 mm circumference apart. Each spermathecal pore flanked by thickened lips, the posterior lip larger. Genital markings not present in spermathecal segments.

Septa 5/6, 6/7, 7/8 thick, 8/9, 9/10 absent, 10/11–13/14 thin. Gizzard globular in VIII–X. Intestine begins in XV, lymph glands absent. Typhlosole small from XXVII. Intestinal caeca simple, originating in XXVII, extending anteriorly to about XXIV, each consisting of a large finger-shaped sac. Hearts XI–XIII oesophageal, IX lateral, X lacking.

Ovaries in XIII. Paired spermathecae in VI, VII; VII larger than VI; each ampulla a large pouch with furrows; ducts as long as ampulla, diverticulum a slender muscular stalk, ectal tightly coiled, ental loosely coiled; no nephridia on spermathecal ducts. Male sexual system holandric, testes and funnels in paired sacs in X, XI, joined ventrally. Seminal vesicles, two pairs filling most of XI, XII. Prostates XVIII centred within XVII–XX; ducts thick, medium length, both glandular portions consisting of three or four main lobes. Medial genital papillae of XVIII with very small sessile gland patches near prostatic ducts, closely attached to surface.

Remarks

Amynthas dabudongensis sp. nov. keys out to the morrisi -group in Sims and Easton (1972). The present species has genital papillae on both sides of the male porophores, in which it differs from other Korean Amynthas . The species is similar to A. tripunctus from West China ( Chen 1946) by the shape of male porophores. The new species has no genital markings, but A. tripunctus has unpaired genital markings in VI, VII, VIII. Also the diverticulum of A. dabudongensis sp. nov. has a coiled shape, but in A. tripunctus it is a simple slender shape. Other morrisi -group species were reported in Beddard (1892, 1895, 1896), Michaelsen (1892, 1923, 1927), Rosa (1894), Gates (1926, 1936, 1968) and Chen (1933, 1936, 1938, 1946), but all these species had different genital marking and genital papillae. The form of the spermathecae and diverticulum are also different.

Figures

Figure 3. Amynthas dabudongensis sp. nov.: ventral view and spermathecae.