Okudrilus monticolus 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 : 28-30

Okudrilus monticolus Csuzdi & Sherlock sp. n.

Figs 5, 6

Etymology: From Latin monticolus (adj.) (mountain dweller) in reference to the type locality, the summit of Mount Oku.

Diagnosis: L: 150–190 mm, D: 5–7 mm. Colour reddish-brown, paler on ventrum. Head epilobous, setae closely paired. Clitellum annular on ½13–18. Prostatic pores in 17/18 a–a, spermathecal pores 12/13 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 45. Ovo-spermathecal apparatus paired, spermathecal ampulla elongated, apically continues in an ovo-spermathecal duct communicating with the ovarian capsule. The right and left ovarian duct interconnected by a small channel. Prostates without copulatory sacs. Simple penial setae 4 mm in length and 0.03 mm in diameter.

Description:

External characters:

Holotype: Preserved length 190 mm, diameter after clitellum 7 mm. Segment number: 274. Paratype: (aclitellate) 155 mm in length, 5 mm in diameter. Segment number: 268. Colour: Preserved dark reddish-brown between setae d–d, paler on ventrum. Head: Epilobous, ½ closed. Dorsal pores: Lacking. Setae: Closely paired, setal ratio aa:ab:bc:cd:dd = 11.2:2:8:1:36. Nephridial pores: Begin on segment 2, somewhat dorsal to setal line d.

Clitellum: Highly glandular, annular on segments ½13–18. Prostatic pores: Ventral on a spectacles-shaped papilla in 17/18, aligned with setal line a–a. Female pores: Small dots on 14, close to the intersegmental furrow 14/15 just below setal line d. Spermathecal pores: Paired on a spectacles-shaped papilla in intersegmental furrow 12/13 between setae a–a ( Fig. 5 ).

Internal characters:

Muscular gizzard: In 6, well-developed, cylindrical. Septa : 6/7, 11/12 thickened, 7/8–10/11 highly strengthened. Calciferous glands: Paired in 12, large curved like a goat-horn, chylus-sacs in 10, 11. Dorsal blood vessel: Simple throughout. Hearts: In 9–11, large moniliform. Testes and sperm funnels: In 11 enclosed in an oval spermreservoir. Seminal vesicles: Long, running alongside the intestine from 12 to 45. Ovospermathecal apparatus: Ovaries in 13 enclosed in an ovarian capsule pendant from septum 12/13. This ovarian capsule medially continuing in an ovarian duct becoming undulating before joining the fertilisation chamber bearing a pendant ovisac. From the fertilisation chamber a straight oviduct leads to the female pore. The ovarian capsule laterally communicates with an ovo-spermathecal duct joining apically to the elongated and muscular spermathecal ampulla. The spermathecal ampulla joins a one-third as long spermathecal duct opening into the spermathecal pore in 12/13. The left and right ovarian ducts communicate by a small interconnecting channel ( Fig. 6 ). Prostates: Long simple tubes without bursa copulatrix or bursa propulsoria. Penial setae: Simple with blunt tip, c. 4 mm long and 0.03 mm in diameter, almost smooth except for the apex which bears fine granulatiOn.

Holotype: CAMEROON: North-West Region, summit of the Oku Mt , 2867-2922 m, 15.vi.2012, T. DohertyBone ( NHM 2013.441 ).

Paratype: Same data as Holotype ( NHM 2013.442 1 preadult ex.) .

Remarks: The new species differs from the other two Okudrilus species in the position of the spermathecal pores located in intersegmental furrow 12/13 (11 in O. sulcatus , 12 in O. nyosensis ) and furthermore in the structure of the ovo-spermathecal apparatus. Habitat consists of loamy soil in high elevation (> 2000 m) sub-alpine grassland.

Figures

Figs5, 6.Okudrilus monticolus sp.n.: (5) ventral view of the clitellar region;(6) ovo-spermathecal apparatus. Abbreviations: Fch=fertilization chamber, Fp=female pore (exits close to intersegment 14/15), Ov=ovarium, Osd=ovo-spermathecal duct, Ovnd=ovarian duct, Ovs=ovisac, Pr=prostate pore, Sta=spermathecal ampulla, Stp=spermathecal pore.