Drawida thomasi Narayanan & Julka

Narayanan, S. Prasanth, Sathrumithra, S., Christopher, G. & Julka, J. M., 2017, New species and new records of earthworms of the genus Drawida from Kerala part of the Western Ghats biodiversity hotspot, India (Oligochaeta, Moniligastridae), ZooKeys 691, pp. 1-18 : 3

Drawida thomasi Narayanan & Julka sp. n.

Type material.

Holotype. Clitellate (Reg. no. ZSI/WGRC/IR/INV-8837), Kozhippara waterfalls (11°21'14.5"N; 76°6'29.2"E) near Kakkadampoyil, Malappuram District, Kerala State, India, 541 m a.s.l., by the side of tuber cultivated field earlier used for coffee plantation, 29 October 2014, S.P. Narayanan and S. Sathrumithra coll.

Paratype. One clitellate and one aclitellate (Reg. no. ZSI/WGRC/IR/INV-8838), same collection data as holotype.

Diagnosis.

Length 55-66 mm, diameter 4.5 mm, segments 66-105. Colour bluish. Male pores in 10/11, large transverse slits, slightly lateral to b lines. Spermathecal pores in 7/8 at c lines. Genital markings absent. Gizzards number 3 in 15-17. Coiled vas deferens mass as large as testis sac; vas discharging directly into prostate dorsally at about its middle. Prostates glandular tubular, slightly bent, prostatic capsule tubular, bent entally. Spermathecal atria bilobed, one lobe in segment 7 and the other in segment 8; atrial lobes tubular, very long, 9-10 mm in length, coiled into compact masses. Nephridiopores aligned with d.

Description.

Colour bluish; body circular, slightly flattened dorsoventrally. Dimension: Holotype 66 mm by 4.5 mm at segment 9, 105 segments; paratypes 55-57.5 mm by 4.5 mm at segment 9, 66-96 segments. Setae lumbricine; some setae on anterior segments may be absent (Table 1); setae ab enlarged on segment 8 and posterioriad segments (Fig. 3A); setal formula aa = 5-7.5 ab = 1.11-3 bc = 5.71-7.5 cd = 0.17-0.31 dd at segment 8, aa = 6.25-14.5 ab = 0.71-1.11 bc = 8.33-14.5 cd = 0.24-0.29 dd at segment 20.

Clitellum annular, at segments 10-13 (= 4 segments), indicated by reddish colour and slight swelling, intersegmental furrows distinct. Spermathecal pores paired, small transverse slits at setae at intersegmental furrow 7/8, aligned with setae c; male pores paired, large transverse slits at intersegmental furrow 10/11, slightly lateral to setae b lines. Genital markings absent. Nephridiopores, present from segment 3, aligned with setae d.

Septa 5/6/7/8/9 slightly muscular. Gizzards 3 in segments 15-17 (holotype and paratypes); intestine begins in segment 24. Last pair of hearts in segment 9; commissures of extra oesophageal vessel present on posterior face of septum 8/9, not recognizable on posterior face of 9/10. Testis sacs paired, in segments 9 and 10, extending to segment 15 on left side and to segment 17 on right side; vas deferens long, coiled in hairpin loops, aggregated into a mass as large as testis sac, discharging directly at about middle of dorsal face of prostate. Prostates paired, glandular, tubular, slightly bent at ental end (Fig. 3B); prostatic capsule shining, smooth, tubular, slightly bent entally (Fig. 3C); prostatic duct about half as long as gland, thick, slightly narrowed before entering parietes. Spermathecae paired, in segment 8; atrium bilobed, one lobe in segment 7 and the other in segment 8, each lobe tubular, very long and coiled into a compact mass occupying entire body cavity of respective segment, 9-10 mm long (when uncoiled); spermathecal duct short with a few coils entering at junction of two atrial lobes (Fig. 3D). Ovarian chamber incomplete; ovisacs paired extending back to segment 16. Nephridia holoic, avesiculate; functional at segment 10.

Etymology. Named after Prof. (Dr.) A.P. Thomas, who initiated taxonomic studies on the earthworms of Kerala state at Advanced Centre of Environmental Studies and Sustainable Development, Mahatma Gandhi University.

Type locality.

Kozhippara waterfalls (11°21'14.5"N; 76°6'29.2"E) near Kakkadampoyil, 27 km away from Nilambur town, Malappuram District, Kerala State, India, 541 m a.s.l., by the side of tuber-ultivated field earlier used for coffee plantation.

Distribution.

Known only from the type locality (Fig. 2).

Ingesta.

Mostly silt, with tiny pieces of mica and organic material.

Biology.

Autotomy is very common. Infested with nematodes in the region of reproductive system.

Habitat.

Bushes with grassy under growth, loamy soil, rich in organic matter, by the side of tuber cultivated field earlier used for coffee plantation.

Remarks.

Drawida thomasi sp. n. belongs to a group of species of Drawida with glandular prostates and bilobed spermathecal atria. It can be easily distinguished from other members of the group, D. robusta robusta (Bourne, 1887), D. robusta ophidioides (Bourne, 1894), D. ghatensis Michaelsen, 1910, and D. somavarpatana Rao, 1921 by the characteristics as given in Table 2.