Glyptothorax primusplicae Shangningam and Kosygin, 2023

Shangningam, Bungdon & Kosygin, Laishram, 2023, Glyptothorax primusplicae, a new species of rheophilic catfish (Teleostei: Sisoridae) from the Chindwin basin, Manipur, Journal of Natural History 57 (33 - 36), pp. 1598-1609 : 1599-1603

Glyptothorax primusplicae Shangningam and Kosygin sp. n.

( Figures 1–2 )

Type material

Holotype: ZSI FF 9461, 73.2 mm SL; INDIA: Manipur, Chandel District, Pamtujang River below Mombi village , a tributary of Chakpi River , Chindwin basin, 24.12555556°N, 93.88444444°E, Shangningam , 23 December 2021.

Paratypes: ZSI FF 9462, 6, 48.5–77.8 mm SL; same data as holotype.

Diagnosis. Glyptothorax primusplicae can be distinguished from all congeners in the Chindwin-Irrawaddy drainage by the presence (vs absence) of plicae on the ventral surface of the pectoral-fin spine and on the first pelvic-fin ray. Further, it can be distinguished from its congeners by the following combination of characters: dorsal fin located nearer to the tip of snout than to adipose fin origin; barbels slender, a nasal barbel reaching anterior margin of the orbit, maxillary barbel extending slightly beyond pectoral-fin base; anterior nuchal plate element visible as a saddle with arrow-shaped extensions when viewed dorsally; thoracic adhesive apparatus longer than broad with a conical-shaped median depression opening caudally; and presence of three stripes on the body.

Description. Morphometric data are given in Table 1 . Body slender. Head depressed with almost rounded snout when viewed dorsally and ventrally. Dorsal profile rising gently from tip of snout to dorsal-fin origin, then sloping gently towards the end of caudal peduncle. Occipital process not in contact with anterior nuchal plate element. Anterior nuchal plate element visible as a saddle with arrow-shaped extensions when viewed dorsally. Ventral profile flat up to vent, slightly convex to end of anal-fin base, then decreasing gently towards caudal-fin base. Caudal peduncle elongate. Skin tuberculate, with small tubercles on sides of body and caudal peduncle.

Eyes small, round, situated on dorsal surface of head. Mouth inferior, premaxillary tooth band partially exposed with mouth closed. Oral teeth small, villiform, in irregular rows on all tooth-bearing surfaces. Barbels in four pairs. Maxillary barbel slender, extending slightly beyond pectoral-fin base. Outer mandibular barbel longer than inner, reaching pectoral-fin base. Nasal barbel long, extending to anterior margin of orbit when adpressed.

Thoracic adhesive apparatus present, longer than broad, consisting of ridges of striae in elliptical field extending from isthmus to level towards posterior end of pectoral-fin base and with a conical-shaped median depression opening caudally ( Figure 2 ). Anteromedial striae absent. Ridges of apparatus not reaching gular region. Anus and urogenital openings located at vertical through posterior middle of adpressed pelvic fin. Lateral line complete, running mid-lateral.

Dorsal fin with i, 6 (7) rays; fin margin convex, located nearer to tip of snout than adipose fin origin. Dorsal-fin spine strong, gently curved, longer than depth of body. Adipose fin with anterior margin straight or very slightly concave, posterior margin angular. Pectoral fin with i, 9 (7) rays; posterior fin margin slightly convex. Pectoral spine broad, covered with thick skin, its posterior margin with 11 (2), 12 (2), 13 (1) or 14 (2) serrae. Pelvic fin with i, 5 (7) rays, its posterior margin slightly convex, surpasses the vent, tip of adpressed fin not reaching anal-fin origin. Ventral surface of pectoral-fin spine plaited and first pelvic-fin ray poorly plaited. Anal fin with ii, 8 (1), 9 (5) or 10 (1) rays, almost straight posterior margin. Caudal fin with 7 + 8 branched rays, strongly forked, with lower lobe slightly longer than upper lobe.

Colouration. In 70% alcohol: dorsal and lateral surface of head and body black, ventral surface up to pelvic fin yellowish. Three yellowish stripes on body: first thick mid-dorsal one, extending behind the end of the dorsal fin, second thin mid-lateral, originating at the level of origin of pectoral fin, and third thick, originating from the end of pelvic fin, stripes reaching caudal-fin base. Dorsal, pectoral, pelvic and anal fins with two black bands, one at bases and another broader at middle of the fins, margins yellowish. Adipose fin black, its origin and distal margin yellowish. Caudal fin brown with yellowish margin. Nasal barbel brown. Maxillary and mandibular barbels yellowish.

In life, body uniformly black. Stripes distinct, yellowish. Fins tinged yellowish-orange.

Distribution. The species is presently known only from the type locality, the Pamtujang River, a hillstream tributary of Chakpi River, Chindwin River basin in Manipur, India ( Figure 3 ).

Habitat. Glyptothorax primusplicae has been collected in rapids and torrential water current with cobbles, boulders and rocky substratum ( Figure 4 ). The fish was collected along with other fish species of the genera Schistura , Mustura , Psilorhynchus , Garra , Devario , Lepidocephalichthys , Barilius , Channa , Pangio and Mastacembelus .

Etymology. The Latin adjective primus means ̍first̾. The species epithet primusplicae is derived from Latin in allusion to the first species having plicae on the ventral surfaces of paired fins in the Chindwin-Irrawaddy River drainage.

Figures

Figure 1. Glyptothorax primusplicae, ZSI FF 9461, holotype,73.2 mm SL:(a) dorsal;(b) lateral; (c) ventral views and freshly caught specimen.

Figure 2. Thoracic adhesive apparatus and ventral surface of pectoral fin showing plicae of Glyptothorax primusplicae, ZSI FF 9461, holotype, 73.2 mm SL.

Figure 3. Map showing the type locality of Glyptothorax primusplicae.

Figure 4. Pamtujang River, the type locality of Glyptothorax primusplicae.