Okudrilus sulcatus Csuzdi & Sherlock, 2015

Csuzdi, Cs., Sherlock, E., Kouete, M. Talla & Doherty-Bone, T. M., 2015, Four new earthworm species from the highlands of Cameroon with description of a new genus Okudrilus gen. n. (Oligochaeta: Eudrilidae & Acanthodrilidae), African Invertebrates 56 (1), pp. 25-38 : 32-33

Okudrilus sulcatus Csuzdi & Sherlock sp. n.

Figs 9, 10

Etymology: From Latin sulcatus (sulcate), in reference to the long seminal grove connecting the prostatic pores and the single porophore.

Diagnosis: L: 70–81 mm, D: 2–2.5 mm. Colour reddish-brown, paler on ventrum. Head epilobous, setae closely paired. Clitellum annular on 14–17. Prostatic pores in 17/18 a–a, spermathecal pores praesetal on 11 between a–a, female pores on 14 close to 14/ 15 in d. Gizzard in 6, calciferous glands in 12, chylus-sacs in 10, 11. Testes in 11, vesicles in 12 long running back to 33. Ovo-spermathecal apparatus paired, spermathecal ampulla elongated, laterally continues in an ovo-spermathecal duct communicating with the ovarian capsule. The right and left ovo-spermathecal duct interconnected by a small channel. Prostates without copulatory sacs. Simple penial setae 4, 4 mm in length and 0.025 mm in diameter.

Description:

External characters:

Holotype: Preserved length 81 mm diameter after clitellum 2 mm. Segment number: 138. Paratype: (tail truncated) 70 mm in length 2.5 mm in diameter. Segment number: 81. Colour: Preserved reddish-brown, paler on ventrum. Head: Epilobous, ¾. Dorsal pores: Lacking. Setae: Closely paired, setal ratio aa:ab:bc:cd:dd = 5.5:1.5:3.5:1:17. Nephridial pores: Begin on segment 2, somewhat dorsal to setal line d.

Clitellum:Annular on segments 14–17. Prostatic pores: Ventral on two spherical papillae in 17/18, aligned with setal line a–a. The prostatic pores are connected by an invert Y-shaped seminal groove with the single asymmetrically placed porophore on 13/14. Female pores: Small dots on 14, close to the intersegmental furrow 14/15 just below setal line d. Spermathecal pores: paired on 11 near to the intersegmental furrow 10/11 between setae a–a ( Fig. 9 ).

Internal characters:

Muscular gizzard: In 6, large, cylindrical. Septa : 8/9–11/12 slightly thickened. Calciferous glands: Paired in 12, chylus-sacs in 10, 11. Dorsal blood vessel: Simple throughout. Hearts: In 9–11, moniliform. Testes and sperm funnels: In 11 enclosed in a spindle-shaped sperm-reservoir. Seminal vesicles: Long, running alongside the intestine from 12 to 33. Ovo-spermathecal apparatus: Ovaries in 13 enclosed in an ovarian capsule pendant from septum 12/13. This ovarian capsule laterally continuing in an undulating ovarian duct joining the fertilisation chamber bearing a pendant ovisac. From the fertilisation chamber a straight oviduct leads to the female pore. The ovarian capsule medially communicates with a short ovo-spermathecal duct joining laterally to the elongated spermathecal ampulla. The spermathecal ampulla joins a spermathecal duct becoming spindle-shaped before opening into the spermathecal pore. The left and right ovarian ducts communicate by a small interconnecting channel ( Fig. 10 ). Prostates: Long simple tubes without bursa copulatrix or bursa propulsoria. Penial setae: Simple, smooth, 4.4 mm long and 0.025 mm in diameter.

Holotype: CAMEROON: North-West Region, Wum , 1230 m, 2005, L. Norgrove ( HNHM AF/5573).

Paratype: CAMEROON: North-West Region, near Elum , 1026 m, 30.v.2012, M. T . Kouete & T . DohertyBone ( NHM 2013.444 1 ex.) .

Remarks: This species differs from the other two Okudrilus in the position of the spermathecal pores located in segment 11 (12/ 13 in O. monticolus , 12 in O. nyosensis ) and furthermore in the structure of the ovo-spermathecal apparatus. The holotype was collected on a Chromolaena odorata two years fallow. The paratype was collected in an area used for subsistence agriculture.

Figures

Figs9, 10. Okudrilus sulcatussp.n.: (9) ventral view ofthe clitellar region;(10) ovo-spermathecalapparatus. Abbreviations:Fch= fertilization chamber,Fp= female pore, Ov =ovarium,Ovnd =ovarian duct, Ovs = ovisac, Pph = porophore, Pr = prostate pore, Sta = spermathecal ampulla, Stp = spermathecal pore.