Tritogenia debbieae, Plisko, 2003

Plisko, Jadwiga Danuta, 2003, Eleven new South African earthworms (Oligochaeta: Microchaetidae) with new information on some known species, and an inventory of the microchaetids of KwaZulu-Natal, African Invertebrates 44 (2), pp. 279-325 : 311-312

Tritogenia debbieae sp. n.

( Fig. 15 )

Etymology: This species is named for Mrs Debbie Jennings, the Collection Manager at the Natal Museum, in appreciation for her extended friendly help.

Material examined: KwaZulu­Natal: Holotype NMSA /Olig.02448 Mooi River (29º12'S: 30º01'E) primary grassland near Road M 3, from moist soil between grassroots, 5 December 1996, JDP, TL. Paratypes: NMSA /Olig.02449, 3 cl + 6 juv, collected with holotype .

Description based on holotype and paratypes.

External characters:

General: body cylindrical, compact after preservation. Colour: grey in life, preserved in formalin whitish­grey. Dimensions: preserved and contracted holotype 48 mm long, 4 mm wide at 10, 5 mm at tubercula pubertatis; paratypes 58–60 mm long, 4–6 mm wide. Segment number: holotype 73; paratype 94. Prostomium: prolobous, clearly separated from first segment. Segmentation: secondary annulation present on preclitellar segments in holotype and paratypes; 1–3 simple, with irregular longitudinal grooves; 4–9 with 2 simple ringlets, similar in size and appearance; 10, clitellar and postclitellar segments simple. Setae: minuscule, closely paired, preclitellarly only ab noted, postclitellarly not observed. Nephridial pores: not observed. Female pores: paired, minute openings in anterior part of 14 in front of ab setae. Male pores: in intersegmental furrow 18/19. Spermathecal pores: not observed externally; during dissection noted close to intersegmental furrows 11/12 and 12/13.

Clitellar region ( Fig. 15 ): Clitellum: not well developed, with thin layer of clitellar tissues; saddle­shaped, segmented, whitish­grey; holotype 13–23; on 13–17 clitellar tissues cover segments dorsally extending only to dorsal edges of tubercula pubertatis. Tubercula pubertatis: on 18,1/n18–1/n22, below ventral edges of clitellum; oval glandular pads, randomly grooved by irregular shallow furrows; ventrally widely separated. Papillae: on 10–18 paired or single, round swellings encircling ab setae, different sizes.

Internal characters:

Septa: 4/5–7/8 thin; other septa in preclitellar segments also thin. Gizzard: large, muscular, in 6–7; commencing abruptly in part of segment 6, extends and occupies whole of 7, terminating at septum 7/8. Calciferous glands: in 9–10, large, dorsolateraly; ventrally separated widely, dorsally by narrow groove. Intestine: commences in 13. Typhlosole: commences in 17 (or 18?), slim, V­shaped, gradually enlarging into U­shaped; terminates in 50. Dorsal blood vessel: double in 4–11; 10–11 enlarged; double when crossing septa 4/5–10/11; in following segments simple. Paired dorsoventral commissural vessels: 4–8 thin, gradually enlarging; 9–11 thick, moniliform. Nephridia : two pairs per segment; small serpentine loops, one pair ventrally, second pair dorsally. Spermiductal funnels: holandric arrangement; two pairs of large, iridescent funnels in 10 and 11 respectively; in holotype right sided sacs slightly smaller than left sided; each pair enclosed in separated sac, connected with vesiculae seminales at septa 10/11 and 11/12 respectively. Seminal vesicles: two pairs of small sacs, linked with testis sacs; in 10 and 11 respectively; posterior pair slightly extending into 12. Spermathecae: in clitellate holotype paired; large, spherical with short neck; ectal parts entering intersegmental furrows 11/12 and 12/13 respectively.In aclitellate paratype with well­developed tubercula pubertatis three spermathecae per segment: 1 at left side, 2 at right side; all globular, different size, iridescent. Ovaries: not observed. Genital glands: in holotype, in some of segments associated with papillae, only at left side of the body, flat, glandular, round structures; in paratype glands not observed.

Biological notes: The species was collected in grassland between the roots of tall grasses. Clitellate, aclitellate and juvenile individuals in different states of development were found in moist soil in the middle of summer. Iridescent sperm in spermathecae was observed in the clitellate individuals and in those with no clitellum. The species was associated with abundant Microchaetus parvus and Microchaetus natalensis .

Distribution: Known only from the type locality, located north­west of Pietermaritzburg ( Fig. 14 ).

Discussion: Having spermathecal pores in two intersegmental furrows 11/12 and 12/13, debbieae is assigned to the sulcata species­group. Lacking thickened septa in preclitellar segments, this species evidently differs from the other congeners.

Figures

Fig. 15. Tritogenia debbieae sp. n., holotype, ventral view with tubercula pubertatis and row of papillae. [P = papilla of segment 14, T = tuberculum pubertatis].

Fig. 14. The distribution of Tritogenia species in KZN. 1 = alveata; 2 = annetteae; 3 = ataxia; 4 = benhami; 5 = crassa; 6 = curiosa; 7 = curta; 8 = debbieae; 9 = diversa; 10 = douglasi; 11 = herbana; 12 = hiltonia; 13 = howickiana; 14 = insolita; 15 = karkloofia; 16 = koilia; 17 = liversagei; 18 = lunata; 19 = melmothana; 20 = miniseta; 21 = monosticha; 22 = morosa; 23 = mucosa; 24 = ngelensis; 25 = ngomensis; 26 = qudeni; 27 = shawi; 28 = soleata; 29 = sulcata; 30 = tetrata; 31 = zuluensis.