Tonoscolex kalimpongensis Ahmed & Julka, 2022

Ahmed, Shakoor, Emiliyamma, K. G., Marimuthu, Nithyanandam, Sajan, Sheikh & Julka, J. M., 2022, A new species of the genus Tonoscolex Gates, 1933 (Clitellata: Megascolecidae) from India, Zootaxa 5124 (3), pp. 375-382 : 376-380

Tonoscolex kalimpongensis Ahmed & Julka , sp. nov.

( Figs 1 & 2 )

urn:lsid:zoobank.org:act:6DB0067B-897F-4E49-84BE-B7EF2C99F4F2

Type material. Holotype: clitellate (ZSI-GNC-An 2203/1), India, West Bengal, Kalimpong District, Neora Valley national park (27.080915°N; 88.697965°E), 2198 m asl, 5 November 2009, leg. Rahul Paliwal and party.

Paratypes: 5 clitellates and 7 aclitellates (ZSI-GNC-An 2204/1), same collection data as for holotype.

Etymology. The species is named after the district where it was collected.

Diagnosis. Medium sized worm, length 80–145 mm, diameter 4–6.5 mm, segments 102–266. Segments 1–4 consisting of a single annulus, segment 5 biannulate, segment 6 triannulate, segment 7 quadriannulate, segment 8 triannulate or quadriannulate, segments 9–12 triannulate. Color brownish, clitellum reddish brown extending from 1/212 – 1/216. Prostomium prolobous. Setae lumbricine. One pair of spermathecal pores, in a transverse slit, slightly median to a, at intersegmental furrow 7/8. Female pores paired, mid-ventral, slightly anterior to the setal line of segment 13. Male pores paired on segment 17 at ab, but close to b setal lines. Gizzard large, single in segment 6. Two pairs of seminal vesicles in segments 11 and 12. Calciferous glands stalked, five pairs in segments 8–12. Prostates strap-shaped, long, extending through segments 17–26. Intestine and typhlosole (lamelliform) beginning in segment 14. Nephridia meroic.

Description of holotype. Body cylindrical. Dimensions: body length 145 mm, width 5.5 mm at segment 8, 4.8 mm at 11 before clitellum, 5 mm at clitellum. Segments 266. Segments 1–4 consist of single annulus, segment 5 biannulate, segment 6 triannulate, segments 7 and 8 quadriannulate, segment 9 and onward triannulate up-to before segment 32 from the posterior end. Body colour light brown, clitellum reddish brown. Prostomium prolobous ( Fig. 1C ). Setae lumbricine, present from segment 2, setal formula aa:ab:bc:cd:dd = 1.1:0.4:1.2:0.5:2.8 at segment 11 and aa:ab:bc:cd:dd = 1.1:0.4:1.3:0.4:3 at segment 22. First dorsal pore on intersegmental furrow 9/10, a pore like appears to be non-functional markings also present on 8/9 ( Fig. 1A ). Clitellum annular extending from the posterior half of segment 12 to anterior half of segment 16 (i.e. covering post setal part of segment 12 and pre setal of segment 16), dorsal pores and setae present. Spermathecal pores one pair, in a transverse slit, slightly ventral to a setal lines, at intersegmental furrow 7/8 ( Fig. 1B ). Female pores minute, paired, median to a in whitish transversely oval area, slightly anterior to the setal line on segment 13 ( Fig. 1B ). Male pores on segment 17 at ab, and close to b setal lines. Male genital shield across segment 17 and anterior part of segment 18, narrower anteriorly than posteriorly, width of the genital shield on ventral 3 mm at segment 17 and 5 mm at segment 18 ( Fig. 1D ). Mid ventral line shield depressed; depression highest in middle of segment 17; with a pair of protuberant areas on both sides with glossy surfaces. Seminal grooves straight, diagonally placed, anterior ends near male pores and posteriorly ends slightly anterior to setae c of segment 18. Ventral setae ab of segment 17 absent whereas cd present.

Septa 6/7–10/11 thickened, 11/12 slightly thickened. Gizzard single, large, cylindrical, in segment 6. Five pairs of kidney-shaped calciferous glands in segments 8–12, with short stalk passing to oesophagus just in front of septa. Each gland partially encircled by hearts of the corresponding segment. Intestine beginning in segment 14. Typhlosole lamelliform, possessing numerous closely set transverse folds along each side, beginning in segment 14 reduced posteriorly and ends in segment 99 ( Fig. 2D ). Last pair of hearts in segment 12. Dorsal blood vessel single passing through gizzard into pharynx. In segments 12–16 a pair of longitudinal trunks present on ventral parietes parallel to nerve cord, each of which gives off four branches on each side. Nephridia meroic, clustered micronephridia present on anterior face of septa of segment 5/6, and enteronephric meganephridia along with micronephridia present only in posterior segments. Testes and funnels in segments 9 and 10, funnels large and iridescent ( Fig. 2A ). Two pairs of seminal vesicles in segments 10 and 11, with whitish spots on dorsal face of vesicles ( Fig. 2A ). Prostates long, strap-shaped, extending from segment 17 to segment 26 ( Figs 2C ). Lateral margin of each prostate incised by septa of segments through which gland passes and median margin smooth. Prostatic ducts emerging from anterior end, looped forward before entrance into parietes in segment 17. Vas deferens commencing from testes segments open into each prostate at its anterior end along lateral side of prostatic duct. Ovaries and oviduct funnels in segment 12 ( Fig. 2A ). One pair of spermathecae in segment 7; ampulla large, ovoid; ducts about half as long as ampulla and narrowing toward ectal end ( Fig. 2B ). Diverticulum finger-shaped, similar length of duct, originating below junction of ampulla at anterior face of the spermathecal duct. Genital marking glands and penial setae absent.

Variation. In a paratype, intersegmental and secondary furrows slightly marked on the clitellum. Prostates long, strap-shaped, extending from segment 17 and bent toward dorsal at segment 23 ( Figs 2E ). Typhlosole beginning in segment 14 reduced posteriorly and ends in segment 105.

Distribution. Known only from type locality ( Fig. 3 and Table 1 ).

Remarks. Tonoscolex kalimpongensis sp. nov. is distinguished easily from all known species of the genus Tonoscolex by the presence of one pair of spermathecal pores in intersegmental furrow 7/8, whereas, other species have two pairs of spermathecal pores in intersegmental furrows 6/7 and 7/8. Furthermore, T. kalimpongensis sp. nov. is closely similar to T. kabakensis Julka, 1981 and T. monorchis ( Stephenson, 1916) by the aspect of five pairs of calciferous glands in segments 8–12. However, it also differs from T. kabakensis and T. monorchis in setal arrangement and seminal vesicles (see Table 2 ). T. kalimpongensis sp. nov. has lumbricine setal arrangement whereas, T. kabakensis has perichaetine setal arrangement. The new species has two pairs of seminal vesicles in segments 10 and 11, in contrast, T. monorchis has three pairs of seminal vesicles in segments 10, 11 and 12. Other difference is the length of the prostate glands which extends in segments 17–26 in T. kalimpongensis sp. nov., segments 17–18 in T. kabakensis and segments 17–19 in T. monorchis .

Figures

FIGURE 1. Tonoscolex kalimpongensis Ahmed & Julka, sp. nov. A. Dorsal view, B. Ventral view, C. Prostomium, D. Male genital region. (cl, clitellum; dp, dorsal pore; fp, female pores; mp, male pores; pr, prostomium; spp, spermathecal pores).

FIGURE 2. Tonoscolex kalimpongensis Ahmed & Julka, sp. nov. A. Internal anatomy, B. Spermatheca, C & E. Prostate glands, D. Typhlosole. (am, ampulla; cg, calciferous glands; di, diverticulum; dv, Dorsal blood vessel; gz, gizzard; he, hearts; in, intestine; ov, ovaries; pd, prostatic duct; pg, prostate gland; sv, seminal vesicles; ti, typhlosole; ts, testes; vd, vas deferens).

FIGURE 3. Distribution localities of species of the genus Tonoscolex recorded in India, red circle represents type locality of Tonoscolex kalimpongensis Ahmed & Julka, sp. nov.