Libyodrilus bipindiensis, Clausen, 2004

Clausen, Martha Weis, 2004, Description of seven new species of Libyodrilus Beddard from Cameroon, with a key to the species of the genus (Oligochaeta: Eudrilidae), Journal of Natural History 38 (15), pp. 1851-1880 : 1853-1855

Libyodrilus bipindiensis n. sp.

(figures 1, 5A, 8C, 11B)

Material examined

Type material. Cameroon, Bipindihof, Bipindi, 3 ‡ 1 ’ N, 10 ‡ 5 ’ E, coll. G. Zauber (holotype: one clitellate, ZMH V-8508; paratypes: two clitellates, three aclitellates, one juvenile, all ZMH). The specimens were found in the same jar (with a single label for all material) as Libyodrilus choristoporus n. sp. State of preservation bad, worms very soft .

External characters (figure 8C)

HOLOTYPE (only complete specimen): length ca 110 mm, diameter 3.5 mm, ca 172 segments. Variation in maximum diameter in paratypes: 3.7–3.8 mm. Annulation only partly visible. Prostomium prolobous. Clitellum orange, rest of body without pigment (fixed specimens). Setal formula: aa: ab: bc: cd ~ 11:1:10:1, dd ~ two-thirds of body circumference at segment 10; 11:1:9:1, dd ~ two-thirds of body circumference at segment 30. No ventral setae but penial setae present at segment 17. Clitellum annular, with 3 K segments in 1/2 14–17. Dorsal pores absent. Nephridiopores not discernible.

Spemarial pore(s) unpaired, or very closely paired (not more than ab apart), m/v in 13 just in front of or in eq surrounded by low circular swelling between a reaching from halfway between 13/14 and eq to 12/13.

Female pores paired, in 15 about 1.5 mm dorsal to d between setal zone and 15/16.

Male pores closely paired (1/2 ab between pores), in 17 in or a little behind eq surrounded by a low, transversely oval swelling between a and covering area from just in front of eq 17 to just behind 17/18. Penial sacs opening just in front of male pores.

Internal characters

First septum 4/5, septa 4/5–12/13 slightly thickened, remaining ones thin. Pharynx extending back to 4/5. Oesophageal gizzards, calciferous glands and ventral sacs absent. Intestine beginning in 19. Intestinal gizzards in 23–25. Sections of gut anterior to gizzards thin-walled, in 24 and 25 with four pouches (two dorsally and two ventrally) next to septa. Median typhlosole from 19. Lateral typhlosole in 27–36.

Blood vessels almost untraceable. Some specimens with bifurcation of dorsal blood vessel visible in some oesophageal segments (vessels bifurcating segmentally, but reuniting when passing through septa).

Excretory system holonephric.

Holandric. Testes not visible (due to bad fixation). Well-developed, multi-plicate funnels with white iridescence in 10 and 11. Paired seminal vesicles in 11 and 12, anterior vesicles restricted to segment 11, posterior ones extending back to 16. Vasa deferentia ending at ectal ends of euprostates. Euprostates (figure 1) tubular, ca 2.5 mm long and 1.0 mm wide, abruptly narrowing ectally before disappearing into parietes at level of male pores.

Penial setae (figure 5A) 1.13 mm long and 0.09 mm wide at ental end. The setae are slightly curving and tapering towards ectal end. (SEM does not show growth striation.)

Spermarium (figure 11B) consisting of median dorsal sac with two branches from anterior corners of sac embracing oesophagus and nerve cord in segment 13 and forming two rings, one around oesophagus and one around nerve cord with a tube between the two rings. Spermarium under nerve cord in connection with spermarial pores through narrow ducts. Perioesophageal ring continuing in an irregular, ca 3-mm-long tube with three diverticula on right and left sides. Diverticula and perioesophageal ring on each side in connection with each other latero-ventral to oesophagus (five adult specimens). In one aclitellate the two posterior diverticula in right side end blindly. No ovaries were seen. Ovisacs lodged in pockets of anterior surface of joined diverticula where these adhere to septum 13/14 and perioesophageal ring. Oviducts leading to female opening in 15 adhering to anterior face of 14/15 ventrally. (Septum 14/15, as in all species of Libyodrilus , displaced posteriad.)

Remarks

Libyodrilus bipindiensis n. sp. and L. choristoporus n. sp. are very similar, but they differ in position of spermarial and male pores as well as in length of euprostatic ducts. As there was no intraspecific variation within the abovementioned characters in six adult specimens of L. bipindiensis , it is most likely that the material represents two new species. However, future collection of more specimens, including specimens of L. choristoporus with penial setae present, might show that this assumption is false.

Libyodrilus bipindiensis belongs together with L. choristoporus n. sp. and (partly) L. maryae n. sp. to group III (table 1). It differs from L. choristoporus by position of the genital pores (figure 8B, C) and length of the euprostatic ducts (figures 1, 2), and from L. maryae by shape and size of penial setae (figures 5A, 6B), and shape of genital field (figure 8A, C).

Distribution Only known from the type locality in southern Cameroon: Bipindihof, Bipindi.

Etymology The species L. bipindiensis is named after the type locality.