Drawida jatinderi Narayanan, 2024

Narayanan, S. Prasanth, Jose, Divya, Kurien, Vijo Thomas & Thomas, A. P., 2024, On three new species of the earthworm genus Drawida Michaelsen, 1900 (Clitellata: Moniligastridae) from south-western India, Zootaxa 5541 (4), pp. 563-581 : 564-567

Drawida jatinderi Narayanan , sp. nov.

( Figure 1A–H )

Type material. Holotype: Aclitellate ( ZSIK Reg.No. ZSI/WGRC/I.R.INV.26787 ), Neriamangalam (10.05497222°N, 76.76191667°E), around 2 km west of Neriamangalam town, Ernakulam District, Kerala State, India, 144 m asl, degraded moist deciduous forest patch, 31 August 2016, collected by S. Prasanth Narayanan and S. Sathrumithra. Paratypes: 3 aclitellates ( ZSIK Reg. No. ZSI/WGRC/I.R.INV.26788 ), same collection data as for holotype .

Other material. 11 aclitellates, 1 juvenile ( ACESSD/EW/1768 ), same collection data as for holotype .

Diagnosis. Length 83–131 mm, width 4–5 mm at segment 9, segments 157–220. Setae present from segment 2. Dorsal pores absent. Spermathecal apertures, concealed in intersegmental furrow 7/8, aligned at C. Secondary male apertures, broad transverse slits, in intersegmental furrow 10/11, at mid BC; male porophores situated either on the tip of an eversible short transversely flat penis or concealed in aperture. Genital markings absent. Gizzards one to three, within segments 13–15. Vas deferens form a mass of loops, mass smaller than testis sac or equal in size, entering prostate directly, in middle glandular portion at its medial side. Prostates paired, glandular, ovoid, erect or bent on itself; prostatic capsule elongate club-shaped, smooth, shiny; prostatic duct with muscular sheen, shorter than gland, ectal end broad sessile slightly dome-shaped on parietes, ental end short, lightly narrower stalk. Spermathecal atrium confined to segment 7, sac-like with muscular sheen, lightly flattened, bend towards posterior side, ectal end marginally narrowed.

Description. External: Colour bluish on dorsum; pale ventrum in life, bluish grey dorsum and pale ventrum in preservation. Body circular in cross section, with slight lateral thickening. Dimensions: Holotype: length 106 mm, width 5 mm at segment 9, segments 154; paratypes: length 102–112 mm, width 4–5 mm at segment 9, segments 157–183; other materials: length 83–131 mm, width 5 mm at segment 9, segments 168–220. Setae lumbricine, minute, closely paired, present from segment 2; setal formula AA = 14.5–16 AB = 1.11–1.28 BC = 14.5–16 CD = 0.34–0.38 DD at segment 8 and AA = 11.5–13.5 AB = 0.74–0.96 BC = 11.5–18 CD = 0.23–0.32 DD at segment 20 (n = 2). Prostomium prolobous. Dorsal pores absent. Clitellum not developed. Spermathecal apertures paired, at intersegmental furrow 7/8, concealed in furrow, with puckered epidermal thickenings that may be present in front and back of spermathecal apertures in segments 7 and 8, aligned at C. Secondary male apertures paired, in broad transverse slits, in intersegmental furrow 10/11, at mid BC setal lines, lateral side of apertures are with tumid lips in segment 10 and 11 ( Fig. 1A ); male porophores situated on tip of eversible short transversely flat penis ( Fig. 1B ). Female pores invisible. Nephridiopores visible from intersegmental furrow 4/5, in single line at CD, throughout. Genital markings absent.

Internal: Brownish pigmentation in circular muscle layer. Septum 4/5 weak, septa 5/6/7/8/9 thickly muscular. Gizzards with reddish-brown longitudinal wrinkles, one to three within segments 13–15, constantly present on segment 14, anterior one smaller; intestine origin in segment 27±1. Last pair of hearts in segment 9; commissures of extra oesophageal vessel present on posterior face of septum 8/9, and 9/10. Testis sac paired, ovoid or with angular ends, confined to segments 9 and 10, not constricted by septum; vas deferens, very long, thin, slender, coiled to form a mass of loops, aggregated mass smaller than testis sac or equal in size, entering prostate directly, in middle glandular portion of prostate at its median side. Prostates paired, glandular (yellowish-white), glandularity reduced to thin layer, ovoid, erect or bend on itself at its junction with prostatic duct, generally towards posterior end, or median to lateral directions ( Fig. 1C, D ); prostatic capsule elongate club-shaped, smooth, shiny ( Fig. 1E, F ); prostatic duct with muscular sheen, shorter than gland, about one fourth of the combined length of gland and duct, ectal end broad sessile, slightly dome-shaped on parietes, ental end short, lightly narrower stalk. Spermathecal ampulla paired in segment 8, ampulla ovoid or elongate ovoid; atrium, confined to segment 7, sac-like with muscular sheen, lightly flattened, bend towards posterior side, ectal end narrowed ( Fig. 1G, H ); duct long, slender, with a few coils on posterior face of septum 7/8, penetrates septum 7/8 close to the body wall, joins atrium in its ectal end, at median side. Ovarian chamber absent; ovisacs paired, short, narrow, thick ectally, tapering towards ental end, confined to segment 12 or extends in segments 12–13. Nephridia holoic, avesiculate.

Variations. On the left side of a specimen, the spermathecal pore is slightly aligned median to C. In the specimen with 3 gizzards, anterior to the gizzard on segment 12, the oesophagus is somewhat swollen but thin-walled, like a very weak gizzard. Similar to this, a specimen with 1 gizzard also had a swollen oesophagus, somewhat like a weak gizzard. Prostate is sometimes lightly flattened lateromedially. In one specimen on the left hand side, the atrium is large and longitudinally placed in segments 7 and 8.

Etymology. Specific epithet ‘ jatinderi’ is a masculine noun in genitive case. The species is named in honour of Dr. Jatinder Mohan Julka, Joint Director (retired), Zoological Survey of India, for his tremendous contributions to the taxonomic and ecological studies on the earthworms of the Indian subcontinent. J.M. Julka mentored and trained the first author on the taxonomical studies on earthworms.

Ingesta. Mainly fine soil, small pebbles, mica, and very few pieces of bark.

Habitat. Degraded moist deciduous forest, close to roadside in the midland of Ernakulam district. Common vegetation of this area is dominated by trees and shrubs such as Terminalia paniculata Roth. , Artocarpus hirsutus Lam. , Alstonia scholaris (L) R. Br., Macranga peltata (Roxb.) Müll.Arg., Caryota urens L., Ailanthus excels Roxb. , Ficus hispida L. f., Olea dioica Roxb. , Tabernaemontana alternifolia Wall. , Helicteres isora L., Mussaenda frondosa L., Ochlandra travancorica (Bedd.) Gamble etc.

Biology. Autotomy and regeneration of lost parts are noticed. Two specimens had regenerated segments (23 and 34 segments) at the posterior end.

Ecology. Appears to be an epi-endogeic species, as indicated by the bluish colour in life and large quantity of fine soil, pebbles, mica, and very few pieces of bark in the intestine. It coexists with D. ghatensis Michaelsen, 1910 , at the type locality.

Distribution. Endemic to India: Kerala State: Ernakulam District: Neriamangalam.

Remarks. Drawida jatinderi sp. nov. belongs to the travancorensis species group. Species of this group are characterized by spermathecal pores at C, male pores at mid- BC, prostate glandular, spermathecal atrium present, dorsal pores, and genital markings absent. Apart from D. jatinderi sp. nov., other species belonging to this group are D. travancorensis Michaelsen, 1910 , and D. thurstoni Gates, 1945 . D. jatinderi sp. nov., can be easily separated from D. travancorensis by the presence or absence of penis (present vs absent), shape of the prostate (ovoid; capsule elongately club-shaped, ental end of prostatic duct short, tapering, ectal end dome-shaped sessile on parietes vs pear-shaped; capsule club-like, prostatic duct enters into a cup-shaped depression in body wall), position of vas deferens opening into prostatic capsule (in middle portion at its median side vs a little below its ental end), and shape of spermathecal atrium (small sized, sac-like, lightly flattened, bend towards posterior side vs simple, slender club-shaped sac or inverted flask-like, ectal end as wide as the rounded body). It can be differentiated from D. thurstoni by body dimension (length: 83–131 mm; width: 4–5 mm vs length: 185–220 mm; width: 7–8 mm), number of gizzards (1–3 vs 5), and type of prostate (ovoid, bend; capsule elongately club-shaped vs mushroom-shaped, erect; capsule vertical ovoid). Characteristics of the travancorensis group members are compared in Table 1 .

Figures

FIGURE 1. Drawida jatinderi Narayanan sp. nov. A. Ventral view of the anterior region; B. Male genital region, ventral view; C, D. Prostate, right side, dorsal view; E, F. Prostatic capsule, right side, dorsal view; G. Spermathecal apparatus; H. Spermathecal atrium, right side, dorsal view. At—Atrium, Pc—Prostatic capsule, Pd—Prostatic duct, Pn—Penis, Pr—Prostate, Sa—Spermathecal ampulla, Sd—Spermathecal duct, Sm—Secondary male aperture, Ts—Testis sac, Vd—Vas deferens.