Amynthas sonjaesiki, 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 : 1243-1244

Amynthas sonjaesiki sp. nov.

( Figure 8 )

Type material

Holotype: Clitellate (NIBRIV0000120469) specimen: Korea, Chungcheongbuk-do Boeun-gun, Mt Songni , 18–22 August 1971, J.S. Son coll. 1 paratype: 1 clitellate (NIBRIV0000120480): Same data as for holotype.

Other material

Same data as for holotype, 4 clitellate specimens.

Etymology

This species is named for its type collector, Son Jaesik.

Diagnosis

Spermathecal pores small white spots 6/7/8, 0.25–0.30 mm circumference apart; male pores 0.29–0.35 mm circumference apart, paired presetal groups of genital papillae medial to male pore indentation.

Description

Dark brown dorsal pigment. Dimensions 92–118 by 5.8–7.0 mm at segment X, 5.5–6.7 mm at XXX, 5.3–5.9 mm at clitellum; body cylindrical throughout, segments 71–97. Setae regularly distributed around segmental equators, numbering 51 at VII, 49 at XX; 14–20 between male pores; setal formula AA: AB: YZ: ZZ = 6: 2.5: 2.5: 4 at XIII. Female pore single in XIV, 0.5 mm, oval shape. First dorsal pore 12/13.

Male pores on large oval porophores markedly protuberant at lateral margins of ventrum in XVIII surrounded by concentric folds; male pore at centre of circular spot within indentation at centre of porophore, 0.29–0.35 mm circumference apart. Remainder of indented area mostly covered with numerous small densely packed genital papillae. Paired presetal groups of genital papillae medial to male pore indentation, 20–28 genital papillae left side, 14–27 on right side. Spermathecal pores small white spots 6/7, 7/8 near lateral margin, slightly thickened lips surround spermathecal pores, 0.25–0.30 mm circumference apart. Paired groups of small genital markings medial to spermathecal pores presetal in VII, VIII; 8–11 per group in VII, 11–16 per group in VIII.

Septa 5/6, 6/7, 7/8 thin, 8/9, 9/10 absent, 10/11–13/14 thin. Gizzard globular in VIII–X. Intestine begins in XV, lymph glands small from about XXXII. Typhlosole absent. Intestinal caeca manicate, originating in XXVII, and extending anteriorly to about XXIII, each consisting of seven or eight finger-shaped lobes, becoming gradually smaller ventrally. Hearts in X–XIII oesophageal, IX lateral.

Ovaries in XIII. Paired spermathecae in VII, VIII; each ampulla large flattened pouch, ducts thick, short; diverticula with long cayenne-pepper-shaped chamber, slender muscular stalk, longer than ampulla; no nephridia on spermathecal ducts. Male sexual system holandric, testes and funnels in ventrally joined paired sacs in X, XI; some individuals have sacs of X halfway in XI, XI half in XII. Seminal vesicles large, two pairs in XI, XII. Prostates XVIII large within XVI–XX, long, thick ducts, both glandular portions consist of three main lobes. Genital papillae of XVIII with stalked glands corresponding approximately in number to externally visible small spots; glands corresponding to genital papillae within male pore indentation very small or absent. Genital marking glands corresponding in number to external markings in paired bundles VII, VIII; each gland with long stalks containing muscle.

Remarks

This species keys to the tokioensis -group in Sims and Easton (1972), but differs from the previously known species in having groups of genital markings in VII and VIII and dense arrays of genital papillae in the presetal part of the male porophores. After 1972, some species were added to the group. The species with simple intestinal caeca are A. zhongi Qiu et Wangwei, 1991 from Guizhou Province, China and A. mujuensis Hong et Kim, 2002 from Korea. All the post-1972 manicate species were collected from Korea. Amynthas vittatus (Goto et Hatai, 1898) , A. levis (Goto et Hatai, 1899) and A. shinkeiensis ( Kobayashi, 1938) also have manicate intestinal caeca. This new species has the manicate type, but it differs from other members from the group with respect to the genital papillae and the shape of male pore region.

Figures

Figure 8. Amynthas sonjaesiki sp. nov.: ventral view and spermathecae.