Eutyphoeus lamdengensis Tiwari & Yadav, 2025

Eutyphoeus lamdengensis Tiwari & Yadav sp. nov.

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Figs 3 View Fig , 14 View Fig ; Tables 1–2 View Table 1 View Table 2

Diagnosis

Length 67–80 mm, diameter 3.6–4 mm, segments 134–150. Prostomium tanylobic. First dorsal pore in 10/11. Male genital orifices in xvii avestibulate, apenile. Single pair of spermathecal pores in intersegment 7/8 large at ab. Female pores paired, presetal, slightly median to setae a. Pairs of genital markings usually on xvi, postsetal at ab sometimes on xi, on xviii single on left side, postsetal at ab; on xii paired, postsetal at ab. Septa 6/7/8 and 11/12 absent. Lateral intestinal caeca small in xxvii, ventrally directed. Holandric. 3–4 pairs of supra-intestinal glands. Prostate extends from xvii–xxi, duct looped twice. Bidiverticulate spermathecae. Penial setae ornamented on anterior end; tip pointed. Sessile genital marking gland present.

Etymology

The etymology of Eutyphoeus lamdengensis sp. nov. is intricately tied to the discovery of the species within the Lamdeng Makhaleikai forest range in Manipur, India. The specific epithet ‘ lamdengensis ’ is derived from ‘Lamdeng’, referring to the geographical location where the species was originally found. The inclusion of ‘ lamdengensis ’ into its scientific name is a tribute to the forest range where this earthworm species naturally resides.

Material examined

Holotype

INDIA – Manipur • clitellate (2–3 segments from the caudal region was taken for DNA extraction); Lamdeng Makhaleikai forest range; 24.8376° N, 93.874° E; elev. 844.306 m; 12 Oct. 2017; Shweta Yadav leg.; registration number – ZSI CZRC T/18; MNP17-1167-47A17 . GoogleMaps

Paratypes

INDIA – Manipur • 3 clitellates; same data as for holotype; MNP17-1158 -47A7 , GoogleMaps MNP17-1166-47A16 , GoogleMaps MNP17-1168-47A18 GoogleMaps .

Description

Holotype

Length 67 mm, diameter 3.6 mm. Total number of segments 134. Prostomium tanylobic. Color wood brown uniformly pigmented. First dorsal pore starts from intersegmental furrow of 10/11 Setae small, aa: ab: bc: cd: dd = 2.03:1:1.69: 1.04:8.34 on xii, aa: ab: bc: cd: dd = 2.93:1:1.90: 1.10:10.93 on xxiv and dd = half circumference. The spermathecal pores in intersegmental region of vii/viii, large at ab, the body wall around the pore fissured. Clitellum covers ⅔ xiii–½ xvii. Female pores paired, presetal, on xiv, slightly median to setae a easily visualized in oval patch which extends between bb. Male genital orifices avestibulate and apenile, on anterior wall below the papillae on segment xvii at b, the paired male papillae oval, and slightly slantwise so that the anterior ends directed away from each other. Each papilla extends from just internal to a, nearly to c, posterior part of the marking without elevation. Genital markings transversely elliptical with fine whitish outer margin, on xvi, paired, postsetal at ab, on xviii single, circular marking on rightside, postsetal, at ab.

Septa 6/7/8 and 11/12 absent, 9/10 thickened. Gizzard in viii extends up to ix. One pair of intramural calciferous glands in xii. A large lymph gland present in xiii–xiv. Intestine begins from xv. Lateral intestinal caeca small in xxvii, ventrally directed. Typhlosole simple lamelliform, begins from xxvii. Nine to twelve ventral intestinal caeca begins from segment xxxiii–lvi. 3–4 pairs of supra-intestinal gland present in segments lxix–lxxiii. Last pair of hearts in xiii. Holandric male organ, seminal vesicles in ix and xii, posterior vesicles extend from xi to xii/xiii, testis sacs in x and xi, anterior one ventral while posterior one annular. Prostate extends from xvii–xxi, duct looped twice. Spermathecae bidiverticulate, lateral, diverticulum stout, club-shaped with 4–5 seminal chambers, ampulla dome-shaped, duct short and wide. Penial setae length 1.45–1.55 mm, width 0.030 mm, ornamented on anterior end with a series of transverse striations, tip pointed, 2 per battery. Paired genital marking glands present in xvi and xvii, sessile.

Variation

Variations were observed in the number and position of the genital marks. In paratype MNP 17-1166- 47A16, a single genital marking present on xi, on the right side, between ab, on xii, paired, postsetal between ab and genital marking absent on segment xviii. In paratype MNP 17-1168-47A18, paired genital marking present on xi; in paratype MNP17-1158-47A7, paired genital markings present on xviii and only one in xix on right side, between ab. In paratype MNP17-1158-47A7, first dorsal pore in 9/10.

Remarks

The novel species Eutyphoeus lamdengensis sp. nov., characterized by avestibulate male genital orifices, holandric testes, paired spermathecal pores in segments vii/viii at ab, and a complete dorsal blood vessel, closely resembles E. phawngpuiensis and is accordingly placed within the hastatus group ( Gates 1958). However, it is distinguished by its unique arrangement of genital markings, ventrally oriented lateral intestinal caeca, and the presence of genital marking glands ( Table 1 View Table 1 ).

DNA barcode

The COI barcode data for the holotype (process ID IEW1121-17) and one paratype (MNP17-1158-47A7, process ID IEW1112-17) has been assigned the BIN number BOLD: ADL1721. In contrast, the other two paratypes, MNP17-1166-47A16 (process ID IEW1120-17) and MNP17-1168-47A18 (process ID IEW1122-17), have been assigned a different BIN number, BOLD: ADL1570. This BIN discordance within the newly discovered species indicates a mean intraspecific divergence of 2.44% and a maximum intraspecific divergence of 3.28% for Eutyphoeus lamdengensis sp. nov. Its nearest neighbor species is Eutyphoeus manipurensis manipurensis , with a nearest neighbor distance of 10.01% ( Table 2 View Table 2 ).