Amynthas baekamensis, 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 : 1239-1241

Amynthas baekamensis sp. nov.

( Figure 6 )

Type material

Holotype: Clitellate (NIBRIV0000120467) specimen: Korea, Jeollanam-do, Jangseong-gun, Mt Baekam , Baekyangsa , 200–400 m, litter layers, 2 August 2000, Y. Hong coll. 1 paratype: 1 clitellate (NIBRIV0000120478): Same data as for holotype.

Other material

Same data as for holotype: 3 semiclitellate; 21 aclitellate; Jeollanam-do, Jangseong-gun, Mt Baekam , Baekyangsa , 200–400 m, litter layers, 20 August 2001, Y. Hong coll.

Etymology

The species is named for its type locality.

Diagnosis

Paired spermathecal pores in VI, VII close to 6/7/8, 0.17–0.18 mm circumference apart; male field with bean-sprout-shaped raised pads, each pad extending from 17/18 to 18/19, 0.15–0.21 mm circumference apart.

Description

Light brown dorsal pigment. Dimensions 73–102 mm by 4.1–4.2 mm at segment X, 4.5–4.8 mm at XXX, 4.3–4.4 mm at clitellum; body cylindrical throughout, segments 89–96. Setae regularly distributed around segmental equators, numbering 65 at VII, 52 at XX; 0 between male pores; setal formula AA: AB: YZ: ZZ = 3: 1.5: 2: 3 at XIII. Female pore single in XIV, 0.3 mm oval shape. First dorsal pore 12/13.

Male field with bean-sprout-shaped raised pads, head end lateral; each pad extending from 17/18 to 18/19; male pores small superficial white spots in 18/19 at posterior ends of paired longitudinally oriented ridges, faint seminal grooves along ridge crests; hardened dark grooves around pad margins, 0.15–0.21 mm circumference apart. Paired spermathecal pores in VI, VII close to 6/7, 7/8, very small, inconspicuous, mid-lateral, spermathecal pores 0.17–0.18 mm circumference apart. Genital markings lacking.

Septa 5/6, 6/7 thick, 7/8 thin, 8/9, 9/10 absent, 10/11–13/14 thin. Gizzard large in VIII–X. Intestine begins in XV, lymph glands from XV. Typhlosole low simple fold from XXVII. Intestinal caeca simple, originating in XXVII, extending anteriorly about to XXI, each consisting of a large finger-shaped sac. Oesophageal hearts X–XIII, IX lateral left large.

Ovaries in XIII. Paired spermathecae in VI, VII; each ampulla small pouch; ducts short, meet body wall in posterior of VI, VII, diverticula shorter than ampulla, chamber tightly coiled; no nephridia on spermathecal ducts, but nephridia dense on body wall of VII. Male sexual system holandric, testes sacs paired, ventral. Seminal vesicles, two pairs XI and XII; enclosed in testes sac in XI. Prostates XVIII extending to XVII–XX; short and thick ducts, both glandular portions consist of two main lobes, each lobe deeply divided into leaflets, prostatic ducts join body wall 18/19. Genital papillae glands lacking.

Remarks

The species has a unique intrasegmental location of the spermathecal pores. Most Korean Amynthas have presetal spermathecal pores, but the species has postsetal pores near the intersegmental furrows. This species with simple caeca is different from the manicate canaliculatus -group, and it is also separated by male field shape. The location of the male pores near 18/19 is also unusual, because Amynthas male pores are usually equatorial.

Figures

Figure 6. Amynthas baekamensis sp. nov.: ventral view and spermathecae.