Kynotus giganteus, . & D]D & Qgudnrwr & Csuzdi & Blanchart, 2011

., D] D, Qgudnrwr, Csuzdi, Cs. & Blanchart, E., 2011, New and little known giant earthworms from Madagascar (Oligochaeta: Kynotidae), African Invertebrates 52 (2), pp. 285-294 : 288-290

Kynotus giganteus sp. n.

Figs 3–5

Etymology: From Latin giganteus (giant), in reference to the size of the captured worms.

Diagnosis: Length alive 1350–1400 mm, diameter 20–25 mm; preserved length 1080–1840 mm diameter 15–20 mm. Colour slightly reddish at the head, pale after the clitellum. Segments 1–2 simple, 3–16 double ringed. Setae ab and cd appear from segment 17. Male pore on 16, on the second ringlet. Clitellum indistinct on 22–47, 48. Setae closely paired, both ab and cd lateral. Spermathecal pores from above ab to Md, 9–14 on each side in 13/14, 14/15, 15/16. Spermathecae intramuscular. Genital setal glands in 14, 15, 16. Genital setae spoon-shaped, slightly tetrahedral. Length ca 6 mm, diameter 0.04 mm, ornamentation dense serrations.

Description:

Holotype: Preserved length 1450 mm, diameter after clitellum 15 mm ( Fig. 3). Segment number: 1330. Paratypes: 1080–1840 mm in length 15–20 mm in diameter. Segment number: 1300–1350. Weight of preserved worms ranges between 184–195g. Colour: Alive slightly reddish at head, whitish after clitellum; preserved greyish. Head: Prolobous. Segments: 1–2 simple, 3–16 clearly double ringed. Dorsal pores: Lacking. Setae: Small, both ab and bc became observable on segment 17. All setae lateral, setal ratio aa: ab: bc: cd: dd = 100:1:10:1:90. Nephridial pores: Begin on segment 2, somewhat dorsal to setal line ab.

Clitellum: Only indistinctly developed on segments 22–47, 48. Male pore: Ventral on 16, large oval slit on second ringlet. Female pores: Small slits on 14, in line of male pores. Spermathecal pores: In intersegmental furrows 13/14, 14/15, 15/16, numerous, 9–14 on each side, begin around the line of nephridial pores and scattered until mid-dorsal line. Spermathecal lines sometimes interrupted and continue not in intersegmental furrow but in furrows of two ringlets. Genital setal pores: Segmental, irregularly occur on lateral sides of segments 14, 15 and 16.

Internal characters: Muscular gizzard: In 5, well-developed, cylindrical. Septa : 5/6, 12/13, 13/14 thickened, 6/7–11/12 highly strengthened. Calciferous glands: Lacking, even lamellar thickening of oesophagus missing. Dorsal blood vessel: Simple. Hearts: In 6–11, large moniliform, especially last two pairs. Testes and sperm funnels: In 10, 11 enclosed in peritoneal sack. Seminal vesicles: Lacking. Ovaries: In 13. Copulatory chamber: Large, oval, occupies the ventral place of segments 15–17. Each copulatory chamber bears irregular prostate-like gland (pseudoprostate) bulging up to segment 13; gland’s position highly variable, sometimes dorsal but sometimes running towards tail. Spermathecae: Small, numerous, completely embedded in body wall, only shining sperm can be seen from inside. Cutting body wall at intersegmental furrow 13/14, several small oval spermathecae can be seen that open to surface with small duct ( Fig. 4). Genital setal organ: Three pairs in segments 14, 15, 16. They consist of large, slightly spiral gland similar in shape to pseudoprostates and genital setal sac containing several genital setae. Genital setae: Spoon-shaped, slightly tetrahedral, ca 6 mm long, 0.04mm in diameter and provided with characteristic serrated ornamentation ( Fig. 5). Holotype: MADAGASCAR: Atsimo-Atsinanana region, Farafangana district, Fianarantsoa town, near YLOODJH RI $QND]RPDIDLWV\ (22°38‵27.8̎6:47°49‵4Ɵ.8̎(), 4ƽ P, 23.L.2ƟlƟ, 0. 5D]D¿QGUDNRWR (+1+0 AF/5513).

Paratypes: Same data as holotype ( HNHM AF/5514 1 ex., ZMUA-030 3 ex.) .

Habitat: The vegetation in the locality is formed by savannah and secondary forest with Ravenala madagascariensis very dominant.

Remarks: The new species exceeds in size all known Kynotus species. It is similar to K. darwini Keller, 1887 (= K. madagascariensis Michaelsen, 1891 ) but differs from the latter in its larger size, the position of the genital setae (13–15 in darwini , 14– 16 in giganteus ) and in the spermathecae (which are intracoelomic and sac-shaped in K. darwini , intramuscular and egg-shaped in K. giganteus sp. n.). Regarding its spermathecal apparatus the new species is similar to K. friderici Michaelsen, 1931 ; however, this species possesses only two spermathecal lines (14/15, 15/16) with 2–2 spermathecae on each side. A further difference can be found in the genital setae, which are claw-shaped in K. friderici and spoon-shaped in K. giganteus sp. n.

It is remarkable that this giant worm possesses very small spermathecae completely embedded in the body wall, similar to several giant Ecuadorian earthworms such as Martiodrilus ischuros Zicsi, 1990 , Martiodrilus crassus (Rosa, 1895) and Martiodrilus olivaceous James, 1990 (each ca 1000 mm long).