Metaphire thabiensis, Tiwari & Yadav, 2025, 2025

Metaphire thabiensis sp. nov.

urn:lsid:zoobank.org:act:8DD33D83-B356-4845-9AAF-6F647E3E5232

Material examined: Holotype: Single clitellate worm (distorted at posterior region) MNP17-1100-44A26 , (reg no.— ZSI CZRC T/7 ), location coordinates-24º38'31"N; 94º14'92"E, Yangoupokpi-Lokchao Wildlife Sanctuary , Tengnoupal , Manipur, collected on- 10 th of October 2017, collected by- Shweta Yadav.

Diagnosis: Species dimension 31mm long, 2mm wide. Prostomium open epilobic. First dorsal pore on ix/x. Male pores in a copulatory pouch in segment xviii. Two pairs of spermathecal pores in intersegmental furrow of vii/viii and viii/ix. Intestinal caeca originate in segment xxv. Holandric. Prostate glands racemose. Spermathecae unidiverticulate, nephridia on spermathecal duct absent. Genital marking gland absent.

Description: Length 31mm approx., diameter 2mm. Total number of segments 126 approx. Prostomium open epilobic. Setae evenly distributed around segmental equators, the number of setae on vii-33, xx-54, with dorsal and ventral gaps. First dorsal pore on ix/x. Spermathecal pore on vii/viii and viii/ix intersegmental, slit-like aperture ( Fig.4a View FIGURE 4 ). Clitellum annular covering xiv–xvi segments, setae unrecognizable on clitellum.Female pore single, median on xiv. Male pore in a copulatory pouch on segment xviii, encircled with oval swollen lining, 1.75mm (0.40x body circumference) apart ventrally, intervened with 5 setae between two male pore ( Fig.4b View FIGURE 4 ). Genital marking absent.

Septa 5/6/7/8 membranous, 8/9/10 absent. Nephridia densely cluster on the anterior faces of segments 5/6, while those of the intestinal segments are positioned on the body wall posterior to the septa. prominent gizzard present in segments viii to x. Intestinal origin in segment xv; caeca originating in segment xxv, extending forward to xviii ( Fig.4c View FIGURE 4 ), while the typhlosole originates in segment xxv. The last pair of hearts in segment xiii. Ovaries and funnels free in segment xiii; spermathecae quadrithecal, located in segments viii and ix. Nephridia on spermathecal ducts absent, with each spermatheca possessing large flipper-like ampullae in segment viii, and somewhat obovoid in ix, duct stout, conical, muscular with flat top, stalked diverticulum attached to the base of spermathecal duct, terminating into club-shaped 6–7 lobed receptacles, stalk moderate ( Fig.4e View FIGURE 4 ). Male sexual system holandric; testes and funnels enclosed in ventral sacs in segments x and xi. Seminal vesicles located in segments xi and xii, with slender vasa differentia attached to the body wall on the way to the ental end of the prostatic ducts. Each prostate racemose, extending from segments xvii to xix, with a muscular duct wrapped around the copulatory bursae, forming a "D" shape and entering the lateral face of the oval (?) copulatory bursa in segment xviii. Coelomic surfaces of the copulatory bursae velvety, lacking secretory diverticula; and penes absent ( Fig.4d View FIGURE 4 ).

Etymology: “thabiensis ” is derived from one of the zones “Khudengthabi” of the Yangoupokpi-Lokchao Wildlife Sanctuary, Manipur the type locality of the species.

Remark

The novel species Metaphire thabiensis is classified within the Metaphire javanica group, characterized by two pairs of spermathecal pores, with the first pair located at segment 7/8. It is holandric, has simple intestinal caeca, lacks stalked glands in the copulatory pouches, and exhibits no post-clitellar genital markings ( Sims & Easton 1972). Initially, Sims & Easton (1972) described 38 species in this group, though several were later synonymized with M. californica and M. javanica . Of these, only four species have been recorded in India and neighboring Southeast Asian regions: M. californica ( Kinberg 1867) (recorded from India), M. kengtungensis ( Gates 1931) and M. lorella ( Gates 1936) (recorded from Myanmar), and M. javanica ( Kinberg 1867) (recorded from Vietnam).

The new species, M. thabiensis , differs from M. californica , M. kengtungensis , M. lorella , and M. javanica in its smaller size and the location of the first dorsal pore. In M. thabiensis , the first dorsal pore is situated at segment ix/x, whereas it is located at segment xi/xii in M. californica , at xii/xiii in both M. kengtungensis and M. lorella , and between segments vi/vii and xiii/xiv in M. javanica .

The structure of the intestinal caeca provides a distinguishing feature for M. thabiensis . In this new species, the caeca originate in segment xxv and extend to segment xviii. In comparison, the caeca of M. californica and M. kengtungensis extend from segment xxvii to xxi, while in M. lorella , they extend from segment xxvii to xix. Similarly, in M. javanica , they extend from segment xxvii to xxiii or xxiv.

A defining feature of M. thabiensis is its male pore, which is surrounded by an oval, swollen lining and opens through a small, transverse, slit-like aperture. In contrast, the male pore is located on a penis in M. kengtungensis and M. lorella , on a small tubercle in M. californica , and on tumescent lips in M. javanica . While the male pore in M. javanica is similar to that of M. thabiensis , it differs in position: in M. javanica , it is 0.20x the body circumference apart, while in M. thabiensis , it is 0.40x the body circumference apart.

A unique characteristic of M. thabiensis is the presence of large, flipper-like ampullae, which are somewhat obovoid in shape, with a stout, conical, and muscular duct with a flat top, further distinguishing this novel species from other members of the group ( Table. 4 View TABLE 4 ).