Amynthas pyeongchangensis, 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 : 1250-1252

Amynthas pyeongchangensis sp. nov.

( Figure 12 )

Type material

Holotype: Clitellate (NIBRIV0000120473) specimen: Korea, Gangwon-do , Pyeongchang-gun , Bangnim-myeon, Mt Baekdeok, 24 August 2001, Y. Hong coll.

Etymology

The species is named for its type locality.

Diagnosis

Three pairs intrasegmental, pre-setal spermathecal pores VI–VIII, 0.26 mm circumference apart; male pores XVIII in large circular papillae within outer ring, each papilla with transverse seminal groove from centre to lateral edge, 0.25 mm circumference apart.

Description

Light brown dorsal pigment. Dimensions 84 mm by 4.2 mm at segment X, 3.8 mm at XXX, 3.7 mm at clitellum; body cylindrical throughout, segments 103. Setae regularly distributed around segmental equators, numbering 25 at VI, 28 at VII, 28 at VIII, 59 at XX; 11 between male pores; setal formula AA: AB: YZ: ZZ = 3: 2: 2: 3 at XIII. Female pore single in XIV, on 0.7 mm oval. First dorsal pore 12/13.

Male pores XVIII in large circular papillae 1.5 × 1.3 mm diameter within outer ring, each papilla with transverse seminal groove from centre to lateral edge, male discs hardened, raised above body wall, 0.25 mm circumference apart. Three pairs spermathecal pores VI, VII, VIII intrasegmental, presetal, small flattened spot; between pores flat asetal area with slight longitudinal furrows forming genital patches, width corresponding to 10–12 setae in adjacent segments, spermathecal pores 0.26 mm circumference apart. Genital markings lacking.

Septa 5/6–7/8 thick, 8/9, 9/10 absent, 10/11, 11/12 thick, 12/13, 13/14 thin. Gizzard in VIII–X. Intestine begins in XV. Typhlosole medium fold from XXVII. Intestinal caeca simple, originating in XXVII, and extending anteriorly about to XXIV, each consisting of a finger-shaped sac, each finger with six or seven small serriform ventral pouches. Oesophageal hearts three pairs in XI–XIII, hearts of XI within testes sac.

Ovaries in XIII. Paired spermathecae in VI–VIII; each ampulla with furrowed large pouch, ducts of medium thickness, shorter than ampulla; diverticula elongate aubergine-shaped, shorter than ampulla; no nephridia on spermathecal ducts. Male sexual system holandric, testes and funnels in ventrally separate, dorsally united sacs in X. Seminal vesicles, two pairs in XI and XII; XI enclosed in testes sacs. Prostates XVIII extending to XVI–XXI; both glandular portions consist of five or six lobes, ducts thick, muscular.

Remarks

The new species keys out to the bournei -group, but is separated easily by the shape of the male pore region with male pores in large hardened, elevated circular discs, each with a transverse seminal groove from centre to lateral edge. The preclitellar segments with asetal regions between the spermathecal pores is also quite distinctive within this species group. Amynthas pyeongchangensis sp. nov. has three pairs of spermathecal pores presetal in VI–VIII. Among the bournei -group, A. mucrorimus , A. pagyeiensis and A. calculatus sp. nov. do not have intrasegmental spermathecal pores close to 5/6/7/8. All Korean bournei -group species have simple intestinal caeca.

Figures

Figure 12. Amynthas pyeongchangensis sp. nov.: ventral view and spermathecae.