Amynthas cucullatus, 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 : 1231-1232

Amynthas cucullatus sp. nov.

( Figure 2 )

Type material

Holotype: Clitellate (NIBRIV0000120463) specimen: Korea, Daegu-si , Dong-gu , Mt Palgong, Pagesa, litter layers in forest, 30 August 2000, Y. Hong coll. 1 paratype: 1 clitellate (NIBRIV0000120475): Same data as for holotype.

Other material

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

Etymology

The name cucullatus is Latin for hood, here referring to the shape of the male pores.

Diagnosis

Spermathecal pores in VI close to 5/6, at the lateral margin, 0.25–0.28 mm circumference apart; male pores superficial within invaginate oval or half-moon male patches, 0.24 mm circumference apart.

Description

Worms unpigmented. Dimensions 74–96 mm (aclitellate 49) by 3.8–4.0 mm at segment X, 4.2–4.3 mm at XXX, 3.7–4.3 mm at clitellum; body cylindrical throughout, segments 72–95. Setae regularly distributed around segmental equators, numbering 63 at VII, 70 at XX; 14–20 between male pores, size distance regular; setal formula AA: AB: YZ: ZZ = 2: 1.5: 1.5: 2 at XIII. Female pore single in XIV, 0.5 mm oval shape. First dorsal pore 12/13. Clitellum annular XIV–XVI; setae invisible, sometimes visible externally.

Male pores superficial near lateral margins of ventrum in XVIII, within invaginate male patches; patches equatorial, 0.8 × 0.5 mm oval or half-moon, within elevated area, male pores under small hoods, 0.24 mm circumference apart, distance between male pores 3.2 mm. Spermathecal pores in VI close to 5/6, at the lateral margin, slightly elevated conspicuous angular porophore, pore openings appear black, spermathecal pores 0.25–0.28 mm circumference apart.

Septa 5/6–7/8 thin, 8/9, 9/10 absent, 10/11 thick, 11/12–13/14 thin. Gizzard large, globular in VIII–X. Intestine begins XV, lymph glands from about XXX, very small. Typhlosole small from XXVII. Intestinal caeca simple, originating in XXVII and extending anteriorly about to XXIII, each consisting of one finger-shaped sac. Oesophageal hearts four pairs in X–XIII, IX lateral left side only.

Ovaries in XIII. Paired spermathecae in VI; ampulla a broad triangular, furrowed pouch, duct short thick, diverticula with slender, muscular stalk, chamber coiled, as long as ampulla or longer than ampulla; no nephridia on spermathecal ducts. Male sexual system holandric, testes and funnels in ventral paired sacs in X, XI. Seminal vesicles XI, XII. Prostates XVIII extending to XVII – XXI; muscular thick ducts, glandular portions consist of two or three main lobes; vas deferens very thin, single.

Remarks

The species has a unique spermathecal arrangement among Korean Amynthas . One pair of spermathecae was found in the Korean A. irregularis (Goto et Hatai, 1899) , but the spermathecae are in VIII, with pores in 7/8. The present species has spermathecae in VI and pores in VI. Most Korean species have two or more pairs of spermathecal pores up to five pairs. Also the species has hooded male pores unlike other Korean species. Hooded male pores occur in some Philippine Amynthas ( Hong and James 2004) and in some species from Taiwan ( James et al. 2005). However, the condition may have arisen independently in these two locations because other characteristics of the species in question are very different. Also the hoods themselves are of a different appearance. The species with hoods were A. philippinensis Hong et James, 2004 , A. mindoroensis Hong et James, 2004 , A. halconensis Hong et James, 2004 from Philippines, and A. huangi James et al., 2005 , A. hengchungensis James et al., 2005 from Taiwan. Only A. philippinensis has one pair of spermathecal pores. However, the spermathecal pores of A. philippinensis are intersegmental on 4/5, but the new species has intrasegmental pores on VI. Also diverticula of A. cucullatus sp. nov. are coiled, but those of A. philippinensis is slender and straight. The Taiwan species have a thick epidermal flap over the male pore, while the male pores in the Philippine species are covered by a thin half-circle of translucent epidermis open medially. Another species with intrasegmental pores in VI is A. mamillaris ( Chen, 1938) ; however, this species is monothecate in VI.

Figures

Figure 2. Amynthas cucullatus sp. nov.: ventral view and spermathecae.