Metaphire churachandpurensis Tiwari & Yadav, 2025

Metaphire churachandpurensis Tiwari & Yadav sp. nov.

urn:lsid:zoobank.org:act:32CB3017-38A8-470F-B09B-6B76F364E543

Material examined: Holotype: One clitellate worm (2–3 segment removed to obtain DNA from the posterior region) MNP17-984-39A1 , (reg no— ZSI CZRC T/23 ), location coordinates- 24º37'28"N; 93º70'97"E, Churachandpur , Manipur, India, collected on- 6 th of Oct, 2017, collected by Shweta Yadav. Paratypes: One mature worm (caudal segment taken for DNA extraction), MNP17-987-39A4 , (reg no. DHSGV-ZDM- 272016018 ), data same as holotype; One mature worm (caudal segment taken for DNA extraction), MNP17-1057-42A16 , (reg no. DHSGV-ZDM- 272016019), location coordinates- 24º25'42"N; 94º29'92"E, 418.8m height, Yangoupokpi-Lokchao Wildlife Sanctuary , Manipur, collected on- 8 th of Oct, 2017, collected by Shweta Yadav; One mature worm (caudal segment taken for DNA extraction), MNP17-1146-46A10 , (reg no. DHSGV-ZDM- 272016020 ), location coordinates- 24º83'59"N; 93º95'00"E, 815.655m height, Heingang , Paddy fields close to Imphal river , Manipur, India, collected on- 12 th of Oct, 2017, collected by Shweta Yadav. Other examined specimens are- MNP17-1050-42A9 , location coordinates-24º25'42"N; 94º29'92"E, 418.8m height, Yangoupokpi-Lokchao Wildlife Sanctuary , Manipur, India, collected on- 8 th of Oct, 2017; MNP17-1140-46A4 , location coordinates-24º83'59"N; 93º95'00"E, 815.655m height, Heingang , Paddy fields close to Imphal river , Manipur, India, collected on- 12 th of Oct, 2017; collected by Shweta Yadav.

Diagnosis: Species dimension ranges from 105–210 mm length, 4.5–6mm width, segments 79–119. Prostomium open-epilobic. The first dorsal pore is located in segments xi/xii, while male pores are present in copulatory pouch in segment xviii. Presence of 6–8 stalked genital marking glands present on copulatory bursae. Intestinal caeca originate in segment xxvii. Holandric. Prostate glands racemose. Spermathecal pore and spermathecae absent.

Description: Length 105–210mm, diameter 4.5–6mm, segments 79–119 (N=7). Dark pigmented dorsum, ventrally pale. Prostomium open epilobic ( Fig. 3a View FIGURE 3 ). First dorsal pore xi/xii. Clitellum annular covering xiv–xvi, prominently demarcated, deep bluish brown. Setae ventrally enlarged while the ventral-most exceptionally enlarged, the number of setae on vii-33, xx-50. Female pore on xiv, surrounded by two light-colored circles, separated by fine dark ring. Male genital region annular, male pore in a copulatory pouch, opens with vertical slit-like aperture, 4.5mm (0.22–0.23x body circumference) apart ventrally, opening shape varies a little in paratypes ( Fig. 3b View FIGURE 3 ). Aperture surrounded by the fissured margin. Little epidermal contraction around the copulatory pouch.

Septa 5/6/7/8–11/12/13/14 thinly muscular, 9/10/11 absent. Dense tufts of nephridia found on the anterior faces of segments 5/6, nephridia of intestinal segments mainly located on the body wall at the anterior and posterior faces of septa, at the junction of septum/body wall. Large gizzard in segments ix to x; esophageal lamellae absent. Intestine originates in segment xiv, caeca originate in segment xxvii, extending forward to segment xxiv, ventrally directed with a wavy margin ( Fig. 3c View FIGURE 3 ); typhlosole originates at segment 22. Hearts located in segments x to xiii; esophageal and commissural vessels found in segments vi, vii, and ix laterally, with those in segment viii extending to the gizzard; the supra esophageal vessel extends from segment x to xiv, with extra-esophageal vessels joining the ventral esophageal wall in segment x. Ovaries and funnels free in segment xiii; spermathecae absent. Male sexual system holandric, with the testis enclosed in paired ventral sacs in segments x and xi; seminal vesicles found in segments xi and xii, granular; vasa differentia slender, embedded in the body wall, passing over the copulatory bursae on the way to join the ental end of the prostatic ducts; prostates located in segments xvii to xx, each racemose, 3–4 lobed, with a muscular duct entering the lateral side of a copulatory bursa ( Fig. 3d View FIGURE 3 ).

Copulatory bursae in xvii to xix oblong shaped, secretory diverticula absent. Coelomic surface of bursae rough, with stalked genital marking glands 6 on the anterior face and two on the posterior face ( Fig. 3e View FIGURE 3 ).

Etymology: Named after the type locality of the species.

Variations: The primary difference observed in the species is the protrusion of copulatory pouch as seen in paratype (MNP17-1057-42A16) the copulatory pouch protrudes out, thus internally the copulatory bursae are not so prominent.

Remark

According to Sims & Easton (1972), the presence and absence of nephridia on the spermathecal ducts is the only characteristic that discriminated between the two genera Pheretima and Metaphire . And, it was unfeasible to discriminate for the athecate forms of the two genera. However, Aspe & James (2014), proposed some other characters to distinguish the two genera, Pheretima and Metaphire , such as variations in the size and shape of the copulatory bursae. According to them, Pheretima species typically exhibit more prominent dome-shaped, intracoelomic copulatory bursae compared to those found in Metaphire . This distinction proves valuable for accurately categorizing athecal worms into either of these genera ( Chang et al. 2009; Aspe & James 2014). Also, according to Sims & Easton (1972), presence of stalked genital marking glands on copulatory bursae is a feature of genus Metaphire . The novel species consists of stalked genital marking glands on the copulatory bursae.

The novel species, Metaphire churachandpurensis , cannot be assigned to any of the Metaphire species groups outlined by Sims & Easton (1972). This is consistent with Metaphire reclusa Yuan & Dong, 2019a , as these groups are primarily defined by the number and position of spermathecae ( Yuan et al. 2019a).

Metaphire churachandpurensis may be mistaken for athecate morphs of M. houlleti , a species characterized by the presence of male pores on segment xviii and the absence of post-clitellar genital markings. However, the new species can be readily distinguished from M. houlleti based on its larger body size, the position of the first dorsal pore, the morphology of the male pore, and the wavy margin of the lateral intestinal caeca.

Additionally, M. churachandpurensis closely resembles Metaphire manipurensis sp. nov. in features such as body size, the position of the first dorsal pore, and the origin of the intestine. However, M. churachandpurensis can be differentiated by the presence of stalked genital marking glands on the copulatory bursae, the wavy lateral intestinal caeca, and the male pore, which opens without lateral expansion on segment xviii.

Interestingly, the trait “copulatory pouches with stalked glands” aligns M. churachandpurensis with the M. insulana group, which includes four species: M. insulana ( Gates 1930) , M. leonoris ( Chen 1946) , Metaphire daliensis Yuan & Dong 2019b , and M. houlletoides Nguyen, Nguyen, Lam & Nguyen 2020 . Within this group, the first dorsal pore in M. churachandpurensis , M. daliensis , and M. houlletoides is located at 11/12, whereas in M. insulana and M. leonoris it is at 12/13. The intestinal caeca in M. churachandpurensis , M. daliensis , and M. insulana are intermediate between simple and complex, while those in M. leonoris and M. houlletoides are simple. Regarding genital marking glands near the prostate, M. churachandpurensis has 6–8 stalked glands on the copulatory bursae, while they are absent in M. daliensis and M. insulana . In M. houlletoides , these glands are visible, whereas in M. leonoris , they are sessile and present in large masses ( Table. 3 View TABLE 3 ).