Dichogaster (Diplothecodrilus) foetida Michaelsen, 1932

Csuzdi, Csaba, 2008, Earthworms from the Kivu Region, D. R. Congo with description of two new Dichogaster Beddard, 1888 (Oligochaeta: Acanthodrilidae, Ocnerodrilidae), Journal of Natural History 42 (33 - 34), pp. 2227-2241 : 2230-2231

Dichogaster (Diplothecodrilus) foetida Michaelsen, 1932

( Figure 2A–D )

Dichogaster foetida Michaelsen 1932, p. 5 .

Dichogaster rubella Michaelsen 1935, p. 64 ; 1936b, p. 46; 1937a, p. 508; 1937b, p. 1, syn. nov.

Dichogaster (Diplothecodrilus) rubella: Csuzdi 1995, p. 13 ; Csuzdi 1996, p. 357; Csuzdi 2000, p. 66.

Material examined

Dichogaster rubella, ZMUH V 12615, Kamatembe 2100 m. Dichogaster rubella, BMNH 1934.4.23.1 Uganda, Kigezi , Kayansa forest 7500 ft (22,500 m), leg. Pittman.

New records. HNHM AF/3540, one exemplar, AF3445, two exemplars, BMNH 1997.1475 – 1476 , two exemplars. D . R. Congo, Kivu Region , Ngungu, leg. Gazsana N’Doli 16 July 1973 . BMNH 1997.1499 , one exemplar. D . R. Congo, Kivu Region , Ngungu, in the swamp, leg. Gasana N’Doli 16 July 1973 . BMNH 1997.1519 , one exemplar. D . R. Congo, Kivu Region , Ngungu, in the swamp, leg. Gasana N’Doli 16 July 1973 . BMNH 1997.1520 – 1523 , four exemplars. D . R. Congo, Kivu Region , Ngungu, leg. Gasana N’Doli 16 July 1973 . HNHM AF/3553, one exemplar, BMNH 1997.1545 – 1547 , three exemplars. D . R. Congo, Kivu Region , Kajabwe, leg. Gasana N’Doli 30 May 1973 .

Diagnosis

Length 50–80 mm, D. 3–4 mm, no. of segments 74–115. Pigmentation brownish. First dorsal pore in 5/6. Clitellum 13–20, 21. ♀ 14 unpaired ventral-median. Prostatic pores 17, 19, genital field oblong. Spermathecal pores 7/8, 8/9, ampoule of the spermatheca elongated with small distal part hardly detached from the long duct. The distal part of the ampoule bears a round and stalked diverticulum. Gizzard in 5/ 6, last pair of hearts in 12. Calciferous glands in 15–17 of equal size. Excretory system meroic with six or seven meronephridia per side. Penial seta L. 1.8–2 mm, D. 0.01 mm, tip hook-shaped, ornamentation a few very fine teeth.

Remarks

Dichogaster (Dt.) rubella was described by Michaelsen (1935). Its description agrees completely with that of D. (Dt.) foetida Michaelsen, 1932 except in the size of the penial setae, which were somewhat larger (1.8–2 mm in D. rubella and 1.6 mm in D. foetida ). However, the type specimen of D. (Dt.) foetida was extremely macerated and from the four penial setal bundles only one seta could have been examined. As the mature setae are usually protruding from the prostatic pores, in macerated specimens they are frequently lost. In this case only the immature replacement setae could be found inside the body and naturally they are of shorter length.

According to the original descriptions both species possess smooth penial setae, but Michaelsen (1935, p. 65) writes ‘‘ Da die sehr zarte Borste sich nicht rein aus der Borstenscheide herauspräparieren und frei untersuchen liess, so möchte ich sicher behaupten, dass eine Ornamentierung fehle.’’ (Since this fragile seta could not be prepared from the setal sac and completely cleared and freely examined, I’m not sure whether ornamentation is lacking.) Examining the penial setae of the present material at higher magnification a few very small teeth were observed at the middle of the seta ( Figure 2C ). This fine ornamentation can easily be overlooked by light microscopy.

Figures

Figure 2. Dichogaster (Dt.) foetida. (A) Ventral part of the clitellar region; (B) penial seta; (C) ornamentation of the penial seta; (D) spermatheca. St, spermathecal pores; Pr, prostate pores.