Glyptothorax ahangkyensis Abonmai and Shangningam, 2025

Glyptothorax ahangkyensis Abonmai and Shangningam View in CoL sp. n.

(Figures 1–3)

HISTORY

Type material

Holotype. ZSI FF 10804, 108.6 mm SL; INDIA: Manipur, Tamenglong District, Ahangky River , a

Barak River drainage, Machengluang village, 25.12028°N 93.80336°E collected by A GoogleMaps . Thonbamliu A GoogleMaps . Phenliangbou, 14 March 2025.

Diagnosis

Glyptothorax ahangkyensis is distinguished from all its congeners in the Indian subcontinent by the combination of characters: presence of reticulated skin ridges on the ventral surface of pectoral first ray of pelvic fin, an ovate leaf-shaped thoracic adhesive apparatus extending from the isthmus level towards the middle of pectoral-fin base, tuberculated skin on the body, posterior margin of dorsal not serrated, pectoral-fin spine with 13–15 serrae, dorsal fin located nearer to the tip of snout adipose-fin origin, nasal barbel short (20.5–25.1% HL), not reaching the anterior margin of the eye, barbels extending beyond pectoral-fin base, anterior nuchal plate saddle-like with W-shaped extensions presence of two longitudinal light brown stripes, one each along mid-dorsal line and lateral line.

Description

Morphometric data are given in Table 1. Body elongated and posteriorly compressed. Head depressed snout rounded when viewed dorsally and ventrally. Dorsal profile rising evenly from tip of snout to dorsal fin, then gently sloping ventrally from dorsal fin to end of caudal peduncle. Ventral profile pelvic-fin origin, then sloping dorsally towards caudal peduncle. Skin tuberculated, with small tubercles side of body and caudal peduncle. Mouth inferior with fleshy papillated lips, upper jaw longer than with teeth on upper jaw in a single lunate-shaped patch, lower jaw interrupted at mid-line. Eyes small

HISTORY situated on dorsal surface of head. Snout length greater than mouth width, anterior and posterior distinctly large, separated by the base of nasal barbel.

Barbels four pairs. Maxillary barbel slender, extending beyond pectoral-fin base; outer mandibular longer than inner, not reaching pectoral-fin base. Inner mandibular barbel shorter, longer than length of outer mandibular barbel. Nasal barbel short, not reaching the anterior margin of eye adpressed. Occipital process not in contact with anterior nuchal plate element. Anterior nuchal plate like with W-shaped extensions when viewed dorsally.

Thoracic adhesive apparatus with an ovate leaf shape, longer than broad, extending from the the level towards the middle of the pectoral-fin base, subulate-shaped median depression which caudally. Anus and urogenital openings located at vertical through posterior middle of adpressed Lateral line complete and mid-lateral.

Dorsal fin with I, 6 rays; fin margin convex, located nearer to tip of snout than adipose-fin origin. spine curved and not serrated posteriorly, shorter than depth of body. Adipose fin with anterior straight, posterior margin slightly convex. Pectoral fin with I, 8–9 rays, posteriorly margin slightly convex pointed tip; pectoral-fin spine broad, covered with thick skin, its posterior margin with 13–15 serrae; surface of pectoral spine and first ray of pelvic fin with reticulated skin ridges. Pelvic fin with i, 5 posterior margin slightly convex surpass the vent, tip not reaching anal-fin origin. Anal fin with ii, posterior margin almost straight. Caudal fin with 7 + 8 branched rays, deeply forked, lower lobe longer than upper lobe. Vertebrae 32.

Colouration

In 10% formalin: dorsal and lateral surfaces of head and body grey or light brown, with black patches body on both sides. Ventral surface of the body to anal fin yellow. Two pale, cream, thin longitudinal on the body; one mid-dorsal and mid-lateral. Base and distal third quarter of dorsal and anal fins with bands; pectoral and pelvic fins black with its margin yellow. Adipose fin black, yellow at the posterior Caudal fin light brown. Nasal, maxillary barbels light brown. Outer and inner mandibular barbels cream outer barbels light brown at the tip.

Distribution

The species is presently known only from the type locality, the Ahangky River in Machengluang Tamenglong District , Manipur (Barak-Meghna-Surma River drainage), India ( Figure 4 View Figure 4 ) .

Habitat

The habitat where the new species was collected comprises swift, turbulent water currents with cobbles and rocky substrates ( Figure 5 View Figure 5 ). The river has a stable and healthy freshwater environment a temperature range of 15–24°C, pH 7.0–8.0, and alkalinity 80–110 mg /L. Riparian forests adjacent to play a critical ecological role. They help regulate water temperature through shading, contribute detritus and allochthonous inputs essential for aquatic food webs, and stabilise banks, thereby erosion and sedimentation.

The new fish species was collected along with other fish species of the genera Barilius, Channa, Garra, Lepidocephalichthys, Mastacembelus, Psilorhynchus and Schistura .

Etymology

The species epithet ahangkyensis is a noun in apposition after the name of the Ahangky Machengluang Village, Tamenglong District, Manipur, India.