Megascolex quadripapillatus Narayanan & Paliwal, 2024

Megascolex quadripapillatus Narayanan & Paliwal View in CoL , sp. nov.

( Figure 1 View FIGURE 1 )

Type material. Holotype: Clitellate ( ZSIK Reg. No. ZSI/ WGRC /I. R.INV.25142), Rani Duduma (18.55091°N, 82.75661°E), around 25 km away from Semiliguda town, Koraput District, Odisha State, India, 960 m a.s.l., near stream in dry deciduous forest, 24 May 2022, collected by Ayusmita Naik. GoogleMaps Paratype: 1 clitellate ( ZSIK Reg. No. ZSI/ WGRC /I. R.INV. 25143), same collection data as for holotype GoogleMaps .

Diagnosis. Large sized; length 273–308 mm, width 9–10 mm at segment 10, 188–190 segments. Prostomium proepilobic, with conspicuous canalicula. Clitellum annular, protuberant, on segments ½13–19 (= 6½), setal arc not visible. Quadrithecal, spermathecal pores conspicuous, transversely placed in intersegmental furrows 7/8/9. Male field light coloured, occupying whole segment 18, male porophore in transverse slits, at the centre of a raised area, setae absent between male pores. Genital markings, two pairs, whitish, transversely elliptical depression, with finite elevated edge, anterior pair, postsetal in segment 17 and protruding into segment 18, posterior pair postsetal occupies whole segment 19 and projecting presetally into segment 20. Penial setae absent. Gizzard, large, muscular, barrel-shaped, in segment 7, septa 7/8/9 pushed posteriorly in funnel-like manner, thus take the spaces of segments 8–9. Oesophagus and gizzard are attached to parietes with several crisscrossed muscular fibres; intestine origin in segment 20. Last pair of hearts in segment 13. Holandric. Prostates large, racemose, erect, incised, lobed, irregularly rectangular mass, flattish, duct rather straight, muscular, moderately stout, hidden in glands, duct shorter than the length of prostate. Spermathecae adiverticulate, close to anterior margins in segments 8 and 9, ampulla large, more or less ovoid, sac-like, somewhat dorsoventrally flattened, striped, posteriorly directed, ampulla and duct well marked off, duct thicker at ental end, duct shorter than the length of ampulla. Genital markings glands absent.

Description. External: Brownish, dark, restricted to dorsum, pale at ventrum; body circular in cross section. Dimensions: Holotype: 308 mm, width 10 mm at segment 10, 190 segments; paratype: 273 mm, width 9 mm at segment 10, 188 segments. Prostomium proepilobic, with conspicuous mid-dorsal groove (canalicula) ( Fig. 1A View FIGURE 1 ). Segments 4–13, biannulate. First dorsal pore concealed in intersegmental furrow 5/6, visible from 6/7 onwards. Clitellum, annular, protuberant, dark coffee brown colour, on segments ½13–19 (= 6½), intersegmental furrows distinct, setal arc not visible, dorsal pores occluded, pale whitish at male field and genital markings.Setae perichaetine throughout, fairly large; setal formula aa = 1.09–1.67 ab = 0.92–1.87 bc = 1–1.25 yz = 0.37–0. 48 zz on segment 12, aa = 2.67–2.75 ab = 2.44–3 bc = 1.33–1.57 yz = 0.92–1.09 zz on segment 24; 58–66 on segment 5, 56–66 on segment 9, 58–66 on segment 12, 65–70 on segment 20, 70–71 on segment 25; 21–22 between spermathecal pores lines on segment 7, setae absent between male pores. Male field light coloured, occupying whole segment 18 ( Fig. 1B View FIGURE 1 ), male pores at the centre of minute transverse slits in slightly raised area, confined to segment 18, in line with ij setal lines, 0.25–0.27 body circumference apart. Female pores minute, paired, presetal, at a, on segment 14. Spermathecal pores paired, conspicuous, transversely placed in intersegmental furrows 7/8/9, in line with setae ijk or jk, 0.26–0.32 body circumference apart. Nephridiopores inconspicuous. Genital markings present, two pairs, pale whitish, transversely elliptical depression, with finite elevated edge, anterior pair, postsetal in segment 17 and protruding into segment 18, posterior pair occupies whole segment 19 and projecting presetally into segment 20 ( Fig. 1B View FIGURE 1 ). Penial setae absent.

Internal: Pigmentation brownish. Septum 5/6 faintly muscular, septa 6/7/8/9 muscular, 9/10/11/12/13 strongly muscular. Oesophagus with large, muscular, barrel-shaped gizzard, in front of septum 7/8, septa 7/8/9 pushed posterior in funnel-like manner, thus take the space of segments 8–9; oesophagus and gizzard are attached to the parietes with several crisscrossed muscular fibres, calciferous gland like swelling present in oesophagus at segments 16 and 17; intestine origin in segment 20; intestinal caeca absent, typhlosole, simple, low ridge-like, lamelliform. Dorsal blood vessel, single and complete; supra esophageal vessel single. Hearts large, last pair of hearts in segment 13; smaller supra-esophageal hearts present in segments 14, 15. Holandric; testis and funnels, paired, free, in segments 10 and 11; seminal vesicles two pairs, racemose, grape-like bunches, in segments 9 and 12. Prostates paired, confined to segment 18, large, erect, thickly racemose, lobed, incised, irregularly rectangular ( Fig. 1C, D View FIGURE 1 ), flattish, adhere to the alimentary canal, nearly touch each other at the dorsal surface, bulging into segments 17–19, by pushing the septa 17/18 and 18/19; prostatic duct, somewhat straight, hidden in glands, muscular, moderately stout, fairly same width throughout, duct shorter than the length of prostate ( Fig. 1D View FIGURE 1 ). Spermathecae two pairs, adiverticulate, close to anterior margins in segments 8 and 9; ampulla large, more or less ovoid, sac-like, somewhat dorsoventrally flattened, transversely striped, longitudinally directed to posterior, ampulla and duct well marked off, duct thicker at ental end where it joins ampulla, lightly narrowed at ectal end, duct shorter than the length of ampulla ( Fig. 1E, F View FIGURE 1 ). Nephridia exonephric, astomate micromeronephridia, scattered randomly in parietes. Genital marking glands absent.

Etymology. The specific epithet ‘ quadripapillatus’ is a morphonym. It is a combination of two Latin words, ‘ quadri ’ and ‘ papilla ’ (four pap i llae). It refers to the presence of four genital markings of this new species.

Ingesta. Large quantity of fibrous plant materials, other organic materials like barks, woody parts, pebbles (including red rock pieces) and gravely soil.

Habitat. Deciduous forest in hilly terrain. As per Champion & Seth (1968) this region of Eastern Ghats has two major forest types, namely tropical dry deciduous and tropical moist deciduous forests. Rani Duduma has dry deciduous forest and the soil is gravely-loamy with rocks and boulders. Common vegetation of this area is dominated by trees, shrubs and climbers such as Terminalia tomentos a, Shorea robusta , Boswellia serrata , Anogeissus latifolia , Pterocarpus marsupium , Dalbergia latifolia , Emblica officinalis , Cassia fistula , Bridellia retusa , Woodfordia fruticosa , Zizyphus oenopli a, Diospyros tomentosa, Lantana camara, Smilax macrophylla , Bauhinia vahlii , Butea superba etc.

Ecology. Appears to be an anecic species, as indicated by large quantity of plant materials and gravely soil in the intestine.

Distribution. Endemic to India: Odisha State: Koraput District: Rani Duduma.

Remarks. Megascolex quadripapillatus sp. nov. belongs to ratus species group, with two pairs of spermathecal pores in intersegmental furrows 7/8/9, penial setae absent, holandric, calciferous glands absent and seminal vesicles in segments 9 and 12. The group consists of four species, including two species described in this communication: M. ratus Cognetti, 1911 , M. pumilio Stephenson, 1916 , M. quadripapillatus sp. nov. and M. jeyporeghatiensis sp. nov. They are compared in Table 1 View TABLE 1 . Among the species of this group, it shows close similarity with M. ratus , in body dimensions, presence of genital markings etc., which is endemic to the Western Ghats (Narayanan et al. 2016, 2023). The differences of these species to M. quadripapillatus sp. nov. are as follows.

M. quadripapillatus sp. nov. is distinguished from M. ratus by the type of clitellum and its extent (annular in segments ½13–19 [= 6½] vs saddle-shaped in segments 14–18 [= 5]), number of genital markings (2 pairs vs several), intestinal origin (in segment 20 vs in segment 14), testis and funnels free vs testis and funnels are enclosed in testis sacs etc. It differs from M. pumilio by the presence of genital markings. In addition, it can also be distinguished from M. pumilio by the large body size, number of clitellar segments, location of the last pair of heart, segmental origin of intestine and the shape of spermathecae. Differences which separate M. quadripapillatus sp. nov. from M. jeyporeghatiensis sp. nov. are the characters of prostate (large, lobed, irregularly rectangular vs fan-like, lightly incised, dorsoventrally flattened), prostatic duct (duct shorter than the length of prostate, unbranched ental portion vs duct equal or lightly longer than the length of prostate, ental portion branched) and condition of spermatheca (adiverticulate vs unidiverticulate) ( Table 1 View TABLE 1 ).