Geogenia Kinberg, 1867

Jadwiga Danuta Plisko, 2006, A systematic reassessment of the genus Microchaetus Rapp, 1849: its amended definition, reinstatement of Geogenia Kinberg, 1867, and erection of a new genus Kazimierzus (Oligochaeta: Microchaetidae), African Invertebrates 47 (1), pp. 31-56 : 39-43

Genus Geogenia Kinberg, 1867 , stat. rev.

Geogenia: Kinberg 1867: 97 ; Perrier 1886: 876; Reynolds & Cook 1976: 52; 1993: 22; Pickford 1975: 23; Brinkhurst & Jamieson 1971: 739.

Microchaeta [partim]: Rosa 1891: 382; 1898: 1; Beddard 1895: 675.

Geogenia ( Microchaeta ?): Michaelsen 1899 b: 428.

Geogenia ( Microchaetus ?): Michaelsen 1891: 38; 1899 b: 428; 1900: 462.

Microchaetus: Michaelsen 1899 b: 428 [redescription of natalensis ]; [partim]: 1900: 448; 1908: 40; 1913 a: 545; 1913 b: 61; 1913 c: 422; 1918: 331; Brook & Dick 1935: 237 [synonyms for pentheri ]; Brinkhurst & Jamieson 1971: 739; Pickford 1975: 23 [partim]; Reynolds 1993: 6; Hodgson & Jamieson 1992: 112 [for pentheri ]; Plisko 1995: 283; [partim]: 1991 a: 279; 1992: 338; 1993 b: 222; 1998: 250; 2002: 205; 2003: 281; 2005: 105; 2006: 34.

Type species: Geogenia natalensis Kinberg, 1867 , by monotypy.

Diagnosis: Testes and male funnels in holandric arrangement. Excretory system holonephric, with nephridial holoic bladders V-shaped. One oesophageal gizzard in segment 7. Dorsal blood vessel double in 4–9, being partly or fully separated when crossing segments, but simple when crossing septa and posterior to septum 9/10; in segment 8 broadly parted, in 9 enlarged, constituting ‘cordiform’ organ. Calciferous glands not stalked, paired or encircling oesophagous, although always with dorsal or ventral vestigial grooves; in one or two segments. Spermathecae and spermathecal pores in pre-testis or testis segments, or post-testicular. If only pre-testicular or post-testicular, pores occur in less than four furrows. If in more than four furrows, pores occur anterior to testis segments, in testis and post-testicular intersegmental furrows. Seminal vesicles two pairs; rarely only one anterior pair. Two, three or four anterior septa (4/5–8/9) variably thickened. Body length of most species between 40–300 mm; some extending to 400 mm, one species reaching 800 mm. Number of segments approx. 100–500.

Comments: Although species of this resurrected genus are quite diverse, they share important features: V-shaped holoic bladders, dorsal blood vessel double in certain anterior segments, and gizzard in segment 7. They differ from Microchaetus (s. str.) in

the lower number and position of post-testicular furrows in which spermathecal pores occur (if there are more furrows with spermathecal pores, some of them occur pretesticularly), in variably thickened certain septa, in smaller body size, and lower number of segments. From the species of Kazimierzus , they differ in the shape of holonephric bladders, and dorsal blood vessel being double in anterior segments.

Thirteen species have all spermathecal pores in post-testicular furrows: pondoana (12/13); zaloumisi (13/14); montana , parva , pentheri , rita, rivus , tuberosa (12/13, 13/14); herberti , idechorita , natalensis (13/14, 14/15); madida (11/12, 12/13, 13/14); ambita (12/13,13/14,14/15). All pores located only in pre-testicular furrows occur in distasmosa and quera (8/9, 9/10), but in namaensis (9/10, 10/11, 11/12) only anterior pores occur in pre-testicular furrow, two others are in immediately post-testis furrows. In caementerii , tegwana and gripha (11/12, 12/13) the anterior pores occur in the furrow immediately posterior to second pair of testes. It is noteworthy that presence of spermathecal pores in 11/12, 12/13 is observed in the majority of proandric species, with testes and male funnels occurring only in segment 10. In gripha and tegwana , proandric reduction of the posterior pair of seminal vesicles is observed, and partial reduction of the posterior pair of vas deferens is noted in tegwana .

Two species, benhami and mkuzi , differ from their congeners in having spermathecal pores in six pre-testicular, testicular and post-testicular furrows, and in extended clitellum and tubercula pubertatis. Their geographical distribution is also exceptional ( Fig. 2 ); benhami is known from cultivated lands in the area of Stellenbosch, Western Cape (Michaelsen 1913 a, b; Pickford 1975, and new material housed in the Natal Museum), whereas mkuzi occurs in natural environments in northern KwaZulu-Natal (Plisko 1992, 1998, 2003).

The species ambita , caementerii , distasmosa , gripha , herberti , idechorita , quera , tegwana , tuberosa and zaloumisi occur in limited areas in KwaZulu-Natal. G. natalensis occurs widely in KwaZulu-Natal, Mpumalanga, Limpopo and neighbouring Swaziland. G. parva is known from numerous sites in KwaZulu-Natal and Mpumalanga; pondoanus occurs widely in Pondoland and neighbouring areas. Species madidus , montana , pentheri , ritae and riva are known only from Eastern Cape. G. namaensis was reported once from Northern Cape (Namaqualand).

Key to the species of Geogenia Kinberg

1 All spermathecal pores in intersegmental furrows posterior to testis segments ... 2

– Not so .................................................................................................................. 17

2 Spermathecal pores in one intersegmental furrow................................................ 3

– Spermathecal pores in more than one furrow ....................................................... 4

3 Spermathecal pores in 12/13; clitellum on 12–20, 21; tubercula pubertatis on 16– 17, 18. Moderate to large, reaching 350 mm....... pondoana (Michaelsen) , comb. n.

– Spermathecal pores in 13/14; clitellum on 13–20; tubercula pubertatis on 16–18. Not exceeding 120 mm ............................................. zaloumisi (Plisko) , comb. n.

4 Spermathecal pores in two furrows ...................................................................... 5

– Spermathecal pores in more than two furrows ................................................... 16

5 Spermathecal pores in 11/12 and 12/13, or in 12/13 and 13/14 ........................... 6

– Spermathecal pores in 13/14 and 14/15.............................................................. 14

6 Spermathecal pores in 11/12 and 12/13 ................................................................ 7

– Spermathecal pores in 12/13 and 13/14 ................................................................ 9

7 Two pairs of seminal vesicles similar size, confined to 10 and 11 respectively. Vasa deferentia double, entering male pores in 17 or 17/18; clitellum on 10–24; tubercula pubertatis prominent, segmented, rimmed, on 16–20; septa 7/8 and 8/9 thickened. Mature individuals large, reaching 800 mm .... caementerii (Michaelsen) , comb. n.

– One pair of seminal vesicle commencing at 10/11, extending posteriorly ........... 8

8 Seminal vesicles extending to 11; posterior pair of male funnels much smaller than anterior; vasa deferentia initially double, enter male pores in 17/18 as simple tube; clitellum on 1/n12–23; tubercula pubertatis as segmented bands on 17–20; typhlosole commences at beginning of intestine in 13. Septa 7/8 and 8/9 thickened. Mature individuals large, 260–350 mm .................................. tegwana (Plisko) , comb. n.

– Seminal vesicles extending to12; male funnels similar size; vasa deferentia paired, and double when entering male pores in 17/18; clitellum on 13–25; tubercula pubertatis rounded at corners on 17–1/n20; typhlosole commences in 19. Mature individuals small, not exceeding 70 mm ....................... gripha (Plisko) , comb. n.

9 Typhlosole commences at beginning of intestine ............................................... 10

– Typhlosole commences posterior to commencement of intestine ...................... 11

10 Two septa 7/8, 8/9 thickened moderately; male pores in 18/19; clitellum on 11, 12–22; tubercula pubertatis as oval ridges on 17–20, n21. Medium sized, approx. 120 mm ............................................................................. ritae (Plisko) , comb. n.

– Four septa 4/5, 5/6, 7/8, 8/9 variably thickened; male pores in 17/18; clitellum on 11, 12–22, 23; tubercula pubertatis sub-rectangular, with shallow furrow at 17/18. Mature individuals medium to large, extending to 400 mm ................................... ...................................................................................... pentheri (Rosa) , comb. n.

11 Typhlosole commences in segment 15. Three septa 4/5, 7/8, 8/9 variably thickened; male pores in 14/15; clitellum on 12–20, n21; tubercula pubertatis sub-rectangular ridges on 16–18. Moderate, approx. 120 mm ............. montana (Plisko) , comb. n.

– Typhlosole commences behind segment 15 ....................................................... 12

12 Typhlosole commences in 17 or 18; septa 4/5, 7/8, 8/9 moderately thickened. Clitellum on 12, 13–22, 13; tubercula pubertatis as oblong narrow swellings on 1/n15, 16–19, 20. Mature individuals small to moderate, not exceeding 100 mm ........................................................................................... riva (Plisko) , comb. n.

– Typhlosole commences in 19; septa 4/5, 7/8, 8/9 variably, moderately thickened ............................................................................................................................ 13

13 Paired seminal vesicle in 10 and 11 respectively, dorsolaterally; clitellum on 12– 21; tubercula pubertatis longitudinal ridges, on 14, 15–17, 18. Mature individuals small, not exceeding 70 mm ................................... parva (Michaelsen) , comb. n.

– Seminal vesicles commencing at septa 10/11 and 11/12 extend dorsolaterally as simple sacs to segments 10 and 11 respectively; clitellum on 13–22; tubercula pubertatis as irregular elongated swellings, segmented, rimmed on 1/n14, 15–18. Moderate in size, extending to 120 mm ..................... tuberosa (Plisko) , comb. n.

14 Only anterior pair of seminal vesicles commencing at septum 10/11, extending to segment 11, and terminating at 11/12; spermathecae paired; septa 7/8 and 8/9 thickened moderately. Typhlosole commences with intestine in 13; male pores in 18; clitellum on 12–21; tubercula pubertatis elongated, glandular, segmented. Mature individuals approx. 115 mm .................................... idechorita (Plisko) , comb. n.

– Two pairs of seminal vesicles in 10 and 11 respectively; spermathecae multiple; septa 4/5, 7/8, 8/9 well thickened ....................................................................... 15

15 Clitellum on 13–22; tubercula pubertatis as glandular strips, with large genital fields; male pores in 16/17. Mature individuals 100–170 mm long .... natalensis Kinberg

– Clitellum on 13–24, 1/n25; tubercula pubertatis as prominent glandular ridges on 1/n15–1/n19; genital fields wide, rimmed; male pores in 15/16. Mature individuals large, reaching 400 mm ............................................... herberti (Plisko) , comb. n.

16 Spermathecal pores in 11/12, 12/13, 13,14; clitellum on 12–24; tubercula pubertatis oval, glandular ridges, on 15–21; male pores in 18/19; septa 4/5, 5/6, 7/8, 8/9 and 9/10 variably thickened; calciferous glands paired in 9. Moderate to large, 100–250 mm ................................................................. madida (Plisko) , comb. n.

– Spermathecal pores in 12/13, 13/14, 14/15; clitellum on 12–25; tubercula pubertatis sub-rectangular, rimmed on 1/n15–1/n20; male pores in 16/17; septa 4/5, 5/6, 7/8, 8/9 moderately and variably thickened; calciferous glands encircling oesophagous in 9. Extending to 300 mm ............................................ ambita (Plisko) , comb. n.

17 All spermathecal pores anterior to testis segments, in intersegmental furrows 8/9 and 9/10 .............................................................................................................. 18

– Some of spermathecal pores anterior to testis segments and in furrows of testis segments, or in pre-testis, testis and post-testis intersegmental furrows ............ 19

18 Clitellum on 11–27; tubercula pubertatis as elongated strips on 19–24; septa 5/6 and 6/7 most thickened, 7/8 and 8/9 thickened little; typhlosole commences in 17; glandular papillae on segments 7–10, 25–27, small globular blisters on 11–18. Moderate, 100–150 mm ................................................ quaera (Plisko), comb. n.

– Clitellum on 1/n11, 12–28, 29; tubercula pubertatis as glandular tubercles on 18, 19–27, 28; septa 4/5, 6/7, 7/8, 8/9 thickened variably; typhlosole commences in 20; glandular papillae variable in size and shape, on segments 5–7 and 11–18. Small, not exceeding 100 mm ................................ distasmosa (Plisko) , comb. n.

19 Spermathecal pores in 9/10, 10/11, 11/12. Clitellum on 10–26; tubercula pubertatis as flattened fields, rimmed, on 17–23; five septa 4/5, 5/6, 6/7, 7/8 and 8/9 variably thickened; calciferous glands encircling oesophagous in 9–10. Moderate, approx. 100 mm ........................................................... namaensis (Michaelsen) , comb. n.

– Spermathecal pores in 10/11–15/16. Larger ....................................................... 20

20 Spermathecae numerous in segment; clitellum on 10–28; tubercula pubertatis on 17–27; septa 4/5, 5/6, 6/7 well thickened. Large, reaching over 300 mm .............. ...................................................................................... benhami (Rosa) , comb. n.

– Spermathecae paired; clitellum on 11–28; tubercula pubertatis on 19–27; septa 4/5, 5/6, 6/7, 7/8, 8/9 variably thickened. Large, exceeding 250 mm .................... ........................................................................................ mkuzi (Plisko) , comb. n.

Figures

Fig. 2. Distribution of Geogenia species indicated as shaded area, with m for mkuzi; b for benhami; n? for namaensis.