Amynthas conferticurtus, 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 : 1241-1242

Amynthas conferticurtus sp. nov.

( Figure 7 )

Type material

Holotype: Clitellate (NIBRIV0000120468) specimen: Korea, Gyeongsangbuk-do, Chilgok-gun, Gasan-myeon , 15 August 1971, E.D. Yeo coll. 1 paratype: 1 clitellate (NIBRIV0000120479): Same data as for holotype.

Other material

Same data as for holotype, 2 clitellate, 1 aclitellate specimens.

Etymology

The name conferticurtus is Latin for densely dark, with regard to the densely placed dark genital papillae.

Diagnosis

Spermathecal pores ventral on anterior edges of VII and VIII, very close to 6/7/8, 0.25–0.35 mm circumference apart; male pores in dark oval areas within elevated pad on which is also one presetal pair of oval or triangular groups of very small densely placed dark genital papillae, 0.26–0.31 mm circumference apart.

Description

Light brown dorsal pigment. Dimensions 85–97 by 4.2–5.2 mm at segment X, 4.3–4.8 mm at XXX, 4.5–5.5 mm at clitellum; body cylindrical throughout, segments 81–92. Setae regularly distributed around segmental equators, numbering 55 at VII, 53 at XX; 15 between male pores, generally regular; setal formula AA: AB: YZ: ZZ = 3: 1.5: 3: 3 at XIII. Female pore single in XIV, 0.3 mm, oval-shaped. First dorsal pore 12/13.

Male pores lateral margins of ventrum in XVIII. Male pore in dark oval areas 0.2-mm diameter, within elevated pad on which is also one presetal pair of oval or triangular groups of three to nine very small densely placed dark genital papillae, 0.26–0.31 mm circumference apart. Spermathecal pores ventral on anterior edges of VII and VIII, very close to 6/7, 7/8 respectively, spermathecal pores 0.25–0.35 mm circumference apart. Each a clear white spot, flat on top, with conspicuous opening. Genital markings presetal paired sets of three to five in segments VII, VIII; placed medial–ventrally to spermathecal pores; genital markings regularly spaced in small dense groups or short lines within each set.

Septa 5/6, 6/7 thick, 7/8 thin; 8/9, 9/10 absent, 10/11–13/14 thin. Gizzard globular in VIII–X. Intestine begins in XV, lymph glands not found. Typhlosole very small from XXVII. Intestinal caeca manicate, originating in XXVII, and extending anteriorly to about XXIV, each consisting of four finger-shaped sacs, more ventral ones becoming gradually smaller. Hearts XI–XIII oesophageal, IX lateral.

Ovaries in XIII. Paired spermathecae VII, VIII; each ampulla a large flattened, or broad slightly furrowed pouch; ducts thick, half the length of ampulla, diverticula with slender stalk, chamber with wide base tapering down towards ends, as long as ampulla; no nephridia on spermathecal ducts. Male sexual system holandric, testes and funnels in ventral paired sacs in X, XI, not clearly connected ventrally. Seminal vesicles, paired in XI, XII, well developed. Prostates XVIII within XVII–XXII, both glandular portions consisting of three main lobes. Genital papillae of XVIII with small stalked glands corresponding approximately in number to externally visible small spots; each gland with small lobes, non-muscular stalk. Genital marking glands paired groups in VII, VIII with large stalked glands corresponding to external genital markings.

Remarks

Amynthas conferticurtus sp. nov. keys out to the pomellus -group in Sims and Easton (1972), which is composed of five species, A. pomellus (Gates, 1935) , A. sucatus ( Chen, 1946) , A. vittatus (Goto et Hatai, 1898) , A. paiki Hong, 2001 and A. fasciiformis Hong et James, 2001 . Both A. pomellus and A. sucatus have simple intestinal caeca, but A. vittatus , A. paiki , A. fasciiformis and A. conferticurtus sp. nov. have manicate intestinal caeca. The present species appears to be closely related to A. fasciiformis , but is separated easily by the shape of the male pore region and the genital papillae because genital papillae of A. fasciiformis are conspicuous and separated from the male pore, but in this species the male pores and genital papillae are quite close to one another. Amynthas paiki has branched genital marking glands and genital papillae glands, but in A. conferticurtus sp. nov. the glands are unbranched. In A. conferticurtus sp. nov. groups of genital markings or genital papillae contain three or more markings/papillae, but A. paiki Hong, 2001 has only two per group.

Figures

Figure 7. Amynthas conferticurtus sp. nov.: ventral view and spermathecae.