Kynotus minutus, Csuzdi, Csaba, Razafindrakoto, Malalatiana & Blanchart, Eric, 2012

Csuzdi, Csaba, Razafindrakoto, Malalatiana & Blanchart, Eric, 2012, New and little known earthworm species from Central Madagascar (Oligochaeta: Kynotidae), Zootaxa 3578, pp. 36-42 : 39-40

Kynotus minutus sp. nov.

( Figs 3–4 , 7 )

Holotype. HNHM AF /5234, Vohimana Reserve, secondary Pandanus forest (18o 55’ S, 48o 29’ E). ca. 800 m. Leg. Csuzdi, Cs., Blanchart, E., Razafindrakoto, M. 17.04.2008.

Paratypes. HNHM AF /5235, three ex., ZMUA-049, one ex., locality and date same as that of the holotype.

Other material examined. HNHM AF /5236, ten aclitellate ex., locality and date same as that of the holotype.

Etymology. The species name refers to the small size of the worms, being the smallest among the presently known kynotids.

Diagnosis. Length 55–70 mm, diameter 3–4 mm. Colour dark red on dorsum, pale on ventrum. Segments 1–3 simple, 4–10 biannulate. Setae ab and cd appear from segment 2. Male pores ventral on 16. Clitellum circular on 18–26, ½27. Setae closely paired, ab ventrolateral, cd dorsolateral. Spermathecal pores between ab and just above cd, 2–3 on each side in 13/14, 14/15, 15/16. Thickened septa lacking. Spermathecae small, egg-shaped. Genital setal glands in 15. Genital setae lanceolate, length 1.1–1.2 mm, diameter 0.04 mm, ornamentation small spines on the ventral and dorsal surface of the setae.

Description. Holotype 61 mm in length, diameter behind clitellum 3.5 mm, number of segments 164. Paratypes 55–70 mm in length, 3–4 mm in diameter, number of segments 168–196. Colour dark red on dorsum, pale on ventrum. Head prolobous, segments 1–3 simple, 4–10 clearly biannulate. Dorsal pores lacking. Setae small, ab and cd became observable from segment 2. Setae ab ventrolateral, cd dorsolateral, setal ratio aa:ab.bc:cd:dd = 13.5:1.5:11: 1:13 ( Fig. 7 ). Nephridial pores begin on segment 2, between setal line ab>cd. Clitellum complete ring on segments 18–26, ½27 ( Fig. 3 ). Male pores ventral, large oval slits on 16. Female pores ventral, small, hardly observable on 14, median to setae a. Spermathecal pores in intersegmental furrows 13/14, 14/15, 15/16, 2–3 on each side, usually between ab and cd. Genital setal pores segmental, on 15.

Internal characters. Large muscular gizzard in 5. Septa all membranous. Calciferous glands, lamellae and typhlosolis lacking. Dorsal blood vessel simple, last pair of hearts in 11. Excretory system holoic, vesiculate, nephridial bladders almost U-shaped, reclinate, provided with a terminal sac. Two pairs of testes and sperm funnels in 10, 11 enclosed in large peri-oesophageal testis sacs. Vesicula seminales lacking. Ovarium in 13. A pair of large, oval copulatory chambers occupying the ventral place of segments 16–18. Each copulatory chamber bearing an irregular prostate-like gland (pseudoprostate) bulging up to the 30th segment. Spermathecae small, egg-shaped, the duct well detached and ca. one third as long as the ampulla. A pair of genital setal organs present in segments 15, consisting of a small gland similar in shape to the pseudoprostates and a genital setal sac containing two mature setae. The genital setae lanceolate, 1.1–1.2 mm in length, 0.04 mm in diameter, ornamentation small spines arranged on the ventral and dorsal surface ( Fig. 4 ).

Remarks. K. minutus sp. nov. is the smallest among the known Kynotidae species. It is somewhat similar to K. alaotranus , however differs from it in the position of the clitellum, the number, size and ornamentation of genital setae and furthermore in the structure of spermathecae. It is similar also to K. parvus sp. nov., but differs from it in the presence of dark red pigmentation, the number, and structure of genital setae and by its smaller dimensions.

Figures

FIGURE 7. Kynotus minutus sp. nov., setal arrangement in cross-section, schematic. FIGURE 8. Kynotus parvus sp. nov., setal arrangement in cross-section, schematic.

FIGURES 3 – 4. Kynotus minutus sp. nov. 3. Dorsal view of the holotype, scale 5 mm. 4. Penial seta. A. The whole seta. B. Tip of the seta. C. Ornamentation.