Perionyx sp. nov.? 1, 2025

Perionyx sp. nov.? 1 View in CoL

Material examined. MNP17-1082-44A8 (a single clitellate, with 2–3 segments from the caudal region taken for DNA extraction), Registration number— ZSI CZRC T/4 Yangoupokpi-Lokchao Wildlife Sanctuary , Tengnoupal District, Manipur State, India, 24.3831°N, 94.1492°E, Manipur, Lat/Lon: 24.3831, 94.1492, collected on October 1, 2017, by Shweta Yadav GoogleMaps .

Diagnosis. Quadrithecal, spermathecal pores on 7/8–8/9. Male pores paired, postsetal, in line with cd, situated on small, rounded papillae facing opposite each other. "V"-shaped longitudinal oblong impression above the male pore. Nephridiopores in a single, irregular rank. Setae approximate: vi/64, ix/54, xii/56, xix/55. First dorsal pore on 3/4. Clitellum annular, spanning xii to xvi. Length 55 mm. Diameter 2.7 mm. Segments approximately 92. Gizzard vestigial in segment v. Intestinal origin in segment xv. Last hearts in segment xii. Nephridia avesiculate. Holandric. Seminal vesicles in segments xi and xii. Calciferous gland-like structure in segment xiii. Prostates in segment xvi, with short duct. Spermathecal ampulla large and sac-like. Ampulla with deeply indented margins. Duct short, wide, and not well-marked off from the ampulla. Diverticulum represented by a ridge, 3–4 iridescent seminal chambers on the anterior face and ental end of the duct. Penial setae absent.

Description. Length 55 mm, diameter 2.7 mm. Number of segments ca. 92 (excluded about 2 mm caudal segments, taken for DNA extraction). Body colour dark brownish purple on the dorsal side, paler on the ventral side. Anterior ventral side up to spermathecal pores with dark red pigmentation. Prostomium open epilobic ( Fig. 3a View FIGURE 3 ). First dorsal pore starts from intersegmental furrow of iii/iv. Perichaetine setal arrangement, closely paired on ventral side. Difficult to count the exact numbers of setae, approximate on segments vi/64, ix/54, xii/56, xix/55, setae between regions of spermathecal pores absent or not visible. Nephridiopores, starts from segment iv, near mL, in a single irregular rank. Clitellum reddish-brown annular rings, extending from segments xii to xvi, with faintly marked intersegmental furrows, setae present. On the last segment of the clitellum, a dorsal pore appears to be present; however, during the dissection, the tissues were disturbed, making it difficult to confirm the presence or absence of the dorsal pore on the clitellum. Clitellum with prominent reddish brown annular rings, from segment xii to xvi. Male genital region pale, a square to oval depression, occupies three segments xv, xvi and xvii, male pores postsetal, in line with cd on xvi or xvii (?), closely situated near the middle line, 1.01mm apart, facing opposite to each other, and on small, rounded papillae. A “V”-shaped longitudinal oblong impression present above the male pore that seems to be raised from each papilla ( Fig. 3b View FIGURE 3 ). Female pore single appears in a white circular patch in front of the setal arc of segment xiii ( Fig. 3b View FIGURE 3 ). Two pairs of mid-ventral spermathecal pores, in intersegmental furrows of segments vii/viii and viii/ix, 0.8mm apart, in line with d ( Fig. 3b View FIGURE 3 ). Genital markings absent.

No septa notably thickened, though vii/viii and viii/ix little thickened. A vestigial gizzard in segment v. Bilobed whitish glabrous intramural calciferous glands like structure without any ridges on the outer surface present in xiii. Intestine originates in xv. Last pair of hearts in xii. Holandric; male organs, testes, and funnels free in segments x and xi, with two pairs of seminal vesicles in xi and xii, those of xi fused together dorsally covering the entire segment and those of xii, long, thin tubular extending up to xxv after segment xx forming an elongated thick lobular structure ( Fig. 3c View FIGURE 3 ). Prostates large compact cuboidal mass in segment xvi, pushing the septa of segment xvi in both directions, and occupy the space of two-three segments. Prostatic duct short, emerges from a deep cleft on the inner surface and becomes fairly stout and shining in its ectal portion. Spermathecae quadrithecal in viii and ix, ampulla large sac like peculiar shaped, margins are the anterior border is deeply indented with two or three rounded lobules similar to the spermathecal ampulla of P. turaensis . Spermathecal duct short and wide and not well marked off from the ampulla. Diverticulum is represented by a ridge consisting of 3–4 iridescent seminal chambers, situated on the anterior face and the ental end of the duct ( Fig. 3d View FIGURE 3 ). Penial setae absent.

DNA barcode. The mitochondrial COI sequence derived from sample MNP17-1082-44A8 with process ID IEW1036-17 has been designated the BIN number BOLD: ADH6243. Upon conducting a blastn search on NCBI, it was determined that the recently identified species exhibits a similarity of 87.86% with Perionyx rufulus , accession number MT431999 View Materials .

Remarks. It is noteworthy to point out that the genital organs of the specimen are positioned one or two segments ahead of their normal location. The female pore was found in xiii, while the male pores was in xvi.

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

However, Perionyx sp. nov.? 1 is distinguished by the first dorsal pore located at 3/4 (compared to 2/ 3 in P. daflaensis and P. daminensis , 4/ 5 in P. minimus , 1/ 2 in P. pullus , and 5/ 6 in P. pulvinatus ). Intestinal origin is in segment xv (compared to xiv in P. daflaensis and P. daminensis , xix in P. minimus , and xvii in P. pullus ), shape of spermathecae and also a distinctive male genital region marked by a "V"-shaped longitudinal oblong impression above the male pore.

Additionally, Perionyx sp. nov.? 1 can be distinguished from P. minimus by the absence of seminal vesicles in segment ix and the presence of iridescent seminal chambers representing diverticula. It also differs from P. pulvinatus by having spermathecal seminal chambers ( Table. 1 View TABLE 1 ).