Acanthodrilus ouenghianus, Csuzdi & Pearlson & Pavlíček, 2017

Csuzdi, Csaba, Pearlson, Oren & Pavlíček, Tomás, 2017, New Acanthodrilus species from New Caledonia (Clitellata, Megadrili, Acanthodrilidae), Journal of Natural History (J. Nat. Hist.) 51 (31 - 32), pp. 1899-1912 : 1906-1907

Acanthodrilus ouenghianus sp. nov.

Figure 4

Type material

Holotype. HNHM / AF5674 , clitellate adult, tail missing. New Caledonia, Ouenghi Agriculture Station , (21.90° S, 166.11° E), cultivated field, 21–28 January 2014, leg. T. Pavlí Č ek and O. Pearson . Paratypes: HNHM / AF5675 one clitellate adult, AF5676 one aclitellate adult, AF5677 two aclitellate adult, AF5678 one clitellate adult . Locality and date same as that of Holotype.

Etymology

The species name refers to the type locality – Ouenghi , New Caledonia .

Diagnosis

L. 265–280 mm. D. 8–9 mm. Average weight 14 g. No. segments 302–316. Colour yellowish. First dorsal pore in 18/19. Clitellum 14–17, saddle-shaped. Prostatic pores paired on protruding papillae, in 17, 19. Penial setae L. 4.25 mm, D. 0.15 mm, ornamentation serrated bars. Spermathecal pores 7/8, 8/9 a–b. Muscular gizzard in 6, calciferous glands lacking. Last pair of hearts in 13. Spermathecae exhibits narrow duct and an equally long oval ampoule. The duct entally bears several small, protruding sperm chambers. Genital setae are lacking.

Description

Holotype. L. 73 mm, D. 8 mm, No. segments 68, tail missing.

Paratypes. 265–280 mm in length, 8–9 mm in diameter, No. segments 302–316, before the clitellum with multiple ringlets (5–6). Colour yellowish, pigmentation missing. Prostomium prolobous, the first dorsal pore occurs in the intersegmental furrow 18/19. Setae closely paired, setal formula after the clitellum aa:ab:bc:cd: dd = 11.3:1.3:10.3:1:43. The clitellum extends over segments 14–17 saddle-shaped, ventral margins reaching setal line a. ( Figure 4a ). Prostatic pores paired on protruding papillae in 17, 19. Male pores externally clearly visible on segment 18, in the laterally highly convex seminal grooves. Female pores paired on 14, small slits anterior to setae a–a. Spermathecal pores large, slightly protruding in furrows 7/8, 8/9 between setae a–b. Nephridiopores aligned just above setal line d. Large unpaired elongated porophores in the furrows 10/11–15/16 between setae b–b, accompanied by a pair of small oval papilla in 16/17.

Internal characters

Septa 8/9, 13/14–14/15 slightly thickened, 9/10–12/13 highly strengthened, others membranous. Oesophageal gizzard large in 6. Calciferous glands lacking, intestine begins in segment 22. Typhlosole as large undulating lamella begins around segment 35. Excretory system holoic, nephridial bladders J-shaped ( Figure 4b ). Paired hearts are present in segments 10–13. Testes are free in 10, 11. Two pairs of seminal vesicles present in 11, 12. A pair of racemose ovaries pendent from the posterior face of the septum 12/13. Two pairs of prostates present in 17, 19. The glands are moderately large occupying two or three segments. Each prostate accompanied by a penial setal sac containing an adult and several replacement setae. The adult seta 4.75 mm in length and the middle 0.16 mm wide, tip elongated spoon-shaped. Ornamentation consists of densely arranged serrated bars ( Figure 4c ). Two pairs of spermathecae present in segments 8 and 9. Each consists of a narrow duct and an equally long, oval ampoule. The ental part of the duct bears several small sperm chambers protruding from the wall of the duct ( Figure 4d ). Genital setae lacking.

Remarks

The new species with its large size, lack of pigmentation and vesicles in 11, 12 seems to be most close to A. koghis Jamieson & Bennett, 1979 . However, it differs from the latter in the form and arrangement of the genital papillae, the size of the penial setae (4.25 vs. 2 mm) and lack of genital setae. A. ouenghianus sp. nov. differs from A. koghis also in the beginning of the intestine (22. vs. 19. segment) and the presence of a well-developed typhlosole.

Figures

Figure 4. Acanthodrilus ouenghianus sp. n. (a) ventral view of the clitellar region; Fp, female pore; Gp, genital papilla; Mp, male pore; Prp, prostate pores; scale bar 4 mm. (b) nephridial bladder from the postclitellar segments. (c) penial seta; scale bar, 0.1 mm. (d) spermatheca.