Perionyx browantlerus Tiwari & Yadav, 2025

Perionyx browantlerus Tiwari & Yadav sp. nov.

urn:lsid:zoobank.org:act:288BC277-EED6-45AB-887D-AC76D824830C

Material examined. Holotype. MNP17-1109-45A6 (a single clitellate, with 2–3 segments from the caudal region taken for DNA extraction), Registration number— ZSI CZRC T/17 , Shirui Kashong (Peak), Shiroi National Park , Ukhrul district, Manipur State, India, 25.1302°N, 94.4202°E, 2106.19 m, collected on October 11, 2017, by Shweta Yadav. GoogleMaps

Etymology. The species name Perionyx browantlerus is derived from the combination of "browantler," referring to the brow-antlered deer ( Rucervus eldii ), the state animal of Manipur, India, where the species was discovered. The brow-antlered deer, also known as the Sangai, is an iconic and endangered species native to the region. The species epithet " browantlerus " honors this majestic animal and highlights the ecological and cultural significance of the region where the earthworm was first identified.

Diagnosis. Quadrithecal, spermathecal pores on 7/8–8/9. Male pores transverse apertures, presetal, on xviii, facing towards each other on small round papillae. Nephridiopores in a single, regular rank. Setae approximate: vi/58, ix/54, xii/60, and xix/66. First dorsal pore on 4/5. Clitellum annular, spanning xiii to xvii. Length 25 mm. Diameter 3.4 mm. Segments approximately 49. Gizzard vestigial in segment v. Intestinal origin in segment xiv. Last hearts in segment xii. Nephridia avesiculate. Holandric. Seminal vesicles in segments xi and xii. Bilobed intramural calciferous glands present in xiii. Prostates in segment xviii, duct short, fairly stout and shining. Spermathecal ampulla elongated sac-like, duct short and wide, diverticulum absent. Penial setae absent.

Description. Length 25 mm, diameter 3.4 mm. Number of segments ca. 49 (excluding approx 2 mm caudal segments taken for DNA extraction). Body colour greyish brown dorsally, paler on ventral side. Darkly bluish pigmentated anteriorly. Prostomium open epilobic. First dorsal pore on iv/v. Perichaetine setal arrangement, closely paired. Setae not prominent, numbers on segments vi/58, ix/54, xii/60, and xix/66. Nephridiopores, starts from segment iv, mL, in a single regular rank. Clitellum a yellowish-brown annular ring, on xiii to xvii, intersegmental furrows lightly marked, setae present, dorsal pores present. Malé genital region has a transversely elongated oval whitish depression that covers the entire xviii segment, in ff or gg. Male pores opens up with a transverse apertures slightly above the setal line on xviii, close to middle line 1.06mm apart, facing towards each other on small round papillae, setae between male pores absent ( Fig. 2a, c View FIGURE 2 ). Female pore single in a white oval patch, presetal on segment xiv ( Fig. 2a, c View FIGURE 2 ). Two pairs of mid-ventral spermathecal pores in an intersegmental furrow of vii/viii and viii/ix, in line with c, 0.7mm – 0.8 mm apart ( Fig. 2a View FIGURE 2 ). Genital markings absent.

No septa notably thickened. A vestigial gizzard in segment v. Intestine originates in xiv. Bilobed intramural calciferous glands present in xiii ( Fig. 2d View FIGURE 2 ). Last pair of hearts in xii. Nephridia avesiculate, with long, slender ducts that extend into the body walls in a regular arrangement on either side. Holandric; testes, and male funnels free in segments x and xi, two pairs of seminal vesicles in xi and xii those of xi fused dorsally occupying the entire segment and those of in xii, a follicular mushroom-like twisted mass that meets dorsally and extends up to xix. Prostates form a compact cuboidal mass in segment xviii ( Fig. 2b View FIGURE 2 ). Septa of the prostatic segment displaced in opposite directions to provide space for the gland. Prostatic duct short, fairly stout, shining, and emerging directly from the middle of the prostatic gland. Spermathecae quadrithecal in viii and ix, ampulla elongated sac-like with a short and wide spermathecal duct, diverticulum absent ( Fig. 2e, f View FIGURE 2 ). Penial setae absent.

DNA barcode. A blastn search on NCBI revealed that the mitochondrial COI sequence from sample MNP17- 1109-45A6, which had the process ID IEW1063-17 and the BIN number BOLD: ADL1419, was 87.86% identical to Perionyx rufulus , which was found with accession number MT431999 View Materials .

Remarks. Perionyx browantlerus sp. nov. belongs to a group of quadrithecal and holandric species, characterized by the presence of spermathecal pores in the 7/8–8/9 intersegmental regions. Within this group, it is closely related to P. pulvinatus Stephenson 1916 , Perionyx sp. nov.? 1, P. daflaensis Julka 1981 , P. daminensis Julka 1981 , P. minimus Stephenson 1920 , and P. pullus Stephenson 1920 , due to the absence of penial setae and the placement of the last pair of hearts in segment xii.

However, P. browantlerus is primarily distinguished by the absence of spermathecal diverticula or seminal chambers, which are present in Perionyx sp. nov.? 1 P. daflaensis, P. daminensis , P. minimus , and P. pullus . Additionally, the first dorsal pore in P. browantlerus is located at 4/5, whereas it is at 3/ 4 in Perionyx sp. nov.? 1, 2/ 3 in P. daflaensis and P. daminensis , 1/ 2 in P. pullus , and 5/ 6 in P. pulvinatus . The intestinal origin in P. browantlerus starts in segment xiv, as opposed to segment xv in Perionyx sp. nov.? 1 and P. pulvinatus , segment xix in P. minimus , and segment xvii in P. pullus . Moreover, P. browantlerus features a unique male genital region, characterized by a transversely elongated oval whitish depression that spans the entire segment xviii. It can also be distinguished from P. pulvinatus by its large, elongated sac-like ampulla, which is short and wide ( Table 1 View TABLE 1 ).