Amynthas tabulatus, 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 : 1245-1246

Amynthas tabulatus sp. nov.

( Figure 9 )

Type material

Holotype: Clitellate (NIBRIV0000120470) specimen: Korea, Gyeongsangnam-do, Geochang-gun, Mt Gaya , Haeinsa , 28 August 1968, Y.J. Yang coll.

Etymology

The species is named for the male pore region, which is flat and hard like a plank.

Diagnosis

Three pairs of spermathecal pores on trailing edges of V–VII, 0.23 mm circumference apart; male pores XVIII, in large circular papillae, each papilla with inverted T-shape seminal groove, discs extend to 17/18, 1/3 XIX, 0.15 mm circumference apart.

Description

Light brown dorsal pigment. Dimensions 130 by 5.3 mm at segment X, 5.0 mm at XXX, 5.0 mm at clitellum; body cylindrical throughout, segments 121. Setae regularly distributed around segmental equators, numbering 42 at VII, 49 at XX; seven between male pores, regular spacing; setal formula AA: AB: YZ: ZZ = 6.5: 3:3: 8 at XIII. Female pore single in XIV, 0.4 mm round. First dorsal pore 12/13.

Male pores XVIII, in large 2.0-mm circular papillae, each papilla with inverted T-shape seminal groove, discs extend to 17/18, 1/3 XIX, hardened, elevated, reddish coloured, some furrows around outer margin, 0.15 mm circumference apart. Three pairs of spermathecal pores on trailing edges of V, VI, VII, ventrally, inconspicuous with some corrugations of segment edges near pores, spermathecal pores 0.23 mm circumference apart. Genital markings absent.

Septa 5/6 thin, 6/7, 7/8 thicken, 8/9, 9/10 absent, 10/11, 11/12 thick, 12/13, 13/14 thin. Gizzard globular in VIII–X. Intestine begins XV, lymph glands not found. Typhlosole simple fold medium height from XXVII. Intestinal caeca simple, originating in XXVII, extending anteriorly to about XXV, each consisting of a finger-shaped small sac with serriform ventral edge. Hearts X–XIII oesophageal, IX lateral.

Ovaries in XIII. Three pairs of spermathecae in VI, VII, VIII; VIII larger than VI and VII; each ampulla a large lanceolate flattened pouch; diverticula with short stalk, large sausage-shaped chamber, shorter than ampulla; no nephridia on spermathecal ducts. Male sexual system holandric, testes, funnels in sacs in X, XI. Sacs X joined dorsally, sacs XI enclosing hearts, seminal vesicles; joined dorsally, ventrally. Seminal vesicles small, two pairs in XI, XII. Prostates in XVIII; muscular short ducts, both glandular portions consisting of two main lobes divided into many leaflets.

Remarks

This is the only Amynthas known to have intrasegmental spermathecal pores on the posterior edges of V–VII. It has an intestinal origin in XVI, zig-zag bent diverticulum chamber, and a simple male porophore with a small pore, and T-shaped seminal groove.

Figures

Figure 9. Amynthas tabulatus sp. nov.: ventral view and spermathecae.