Glyptothorax viridis, Shangningam & Kosygin, 2023

Shangningam, Bungdon & Kosygin, Laishram, 2023, Glyptothorax viridis, a new species of catfish (Teleostei: Siluriformes: Sisoridae) from Manipur, India, Zootaxa 5315 (1), pp. 83-93 : 86-89

Glyptothorax viridis , new species

( Figs. 1–2 )

Type material. Holotype: ZSI FF 9463, 87 mm SL; India: Manipur, Chandel District, Dujang River at Dutuwl below Khubung Khullen , a tributary of the Chakpi River , Chindwin basin, 24º07ꞌ32.39ꞌꞌ N 93º53ꞌ04.49ꞌꞌ E, Shangningam , 23 December 2021.

Paratypes: ZSI FF 9464, 4 ex, 74.0– 87.2 mm SL; same data as holotype .

Diagnosis. Glyptothorax viridis is distinguished from all congeners in the Chindwin drainage in having plicae on ventral surface of pectoral-fin spine, and on first pelvic-fin ray, and thoracic adhesive apparatus with deep cone-shape median depression opening caudally. It is further distinguished by having the following combination of characters: thoracic adhesive apparatus with anteromedial striae; slender nasal barbel reaching anterior orbital margin; strong dorsal spine; branched pectoral-fin rays 9 with 9–10 serrae on posterior margin of pectoral spine, and slender pelvic fin reaching anal fin.

Glyptothorax viridis is distinguished from all congeners in the Chindwin-Irrawaddy drainage, except G. trilineatus and G. ventrolineatus in having three stripes on the body. However, it can be distinguished from G. ventrolineatus and G. trilineatus ( Fig. 3 ) in having an oval field thoracic adhesive apparatus with deep cone shaped median depression (vs. elliptical thoracic adhesive apparatus with triangular shaped median depression in G. ventrolineatus ; vs. rhomboidal thoracic adhesive apparatus with narrow median depression in G. trilineatus ). Furthermore, it differs from G. ventrolineatus in having greater head width (19.2–21.8 % SL vs. 12.3–14.5), longer anal fin (19.2–22.7 % SL vs.13.8–15.8), greater head depth at occiput (54.1–63.6 % HL vs. 39.5–46.3), dorsal spine not serrated (vs. serrated), dorsal fin nearer to adipose-fin origin than to tip of snout (vs. dorsal fin located midway between tip of snout and adipose-fin origin) and fewer unbranched anal-fin rays (ii vs. iii); and from G. trilineatus in having a slender nasal barbel reaching (vs. not reaching) anterior margin of orbit, maxillary barbel reaching beyond posterior end of pectoral-fin base (vs. reaching anterior base of pectoral fin), shorter preanal length (64.4–67.9 % SL vs. 68.2–68.4), and presence (vs. absence) of tubercles on fins.

Description. Morphometric data in Table 1 . Body slender. Head depressed with truncate snout when viewed dorsally and ventrally. Dorsal profile rising from tip of snout to dorsal-fin origin, then sloping towards end of caudal peduncle. Skin on body with tuberculations. 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. 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 to end of 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 an oval field extending from isthmus to level towards middle of pectoral-fin base and with deep, cone-shaped median depression opening caudally. Median ridges oriented longitudinally, lateral ones radiating from median depression, few branched at anterior and posterior ends. Anteromedial striae present. Ridges of apparatus not reaching gular region. Anus and urogenital openings located at vertical through posterior mid of adpressed pelvic fin. Lateral line complete, running mid-lateral.

Dorsal fin with i, 6 (5) rays; fin margin convex, located nearer to adipose-fin origin than to tip of snout. Dorsal-fin spine strong, shorter than depth of body. Adipose fin with anterior margin straight or very slightly concave, posterior margin angular. Pectoral fin with i,9 (5) rays; posterior-fin margin almost convex. Pectoral spine broad, covered with thick skin, its posterior margin with 9 (2) or 10 (3) serrae. Pelvic fin with i,5 (5) rays, its posterior margin slightly convex, surpasses vent, tip of adpressed fin reaching anal-fin origin. Ventral surface of pectoral-fin spine plaited, and first pelvic-fin ray plaited with rows of plicae. Anal fin with ii, 9 (5) rays. Caudal fin with 8+7 (5) branched rays, strongly forked, with lower lobe slightly longer than upper lobe.

Coloration. In 70 % alcohol: dorsal and lateral surface of head and body brownish-black, ventral surface up to pelvic-fin pale yellow. Three yellow stripes on body: first one, thick and mid-dorsal, extending behind end of dorsal fin; second thin, midlateral, originating at level of origin of pectoral fin; and third thick, originating from end of pelvic fin, with stripes reaching caudal-fin base. Dorsal, pectoral, pelvic and anal-fins with two black bands, first thin band at base, and broad one at middle of the fin, margins whitish-yellow. Adipose fin yellow, with broad black band in middle. Caudal fin brownish yellow with black rays. Nasal barbel pale brown. Maxillary barbel with broad black base, and mandibular barbel pale yellow.

In life, body uniformly green ( Fig. 4 ). Stripes distinct yellow. Fins tinged yellowish-orange and caudal fin yellowish-brown.

Distribution. The species is presently known only from the type locality, the Dujang, a hillstream tributary of Chakpi River, Chindwin River basin in Manipur, India ( Fig. 5 ).

Habitat. Glyptothorax viridis was collected in rapids with cobbles, boulders and rocks as substrate. The fish was collected along with species of the genus Schistura, Mustura, Psilorhynchus, Garra and Mastacembelus .

Etymology. The species name ‘ viridis’ is derived from Latin meaning green, alluding to the color pattern of live individuals.

Figures

FIGURE 1. Glyptothorax viridis, ZSI FF 9463, holotype; a, dorsal; b, lateral; c, ventral views.

FIGURE 2. Ventral surface of pectoral fin of Glyptothorax viridis, ZSI FF 9464, paratype.

FIGURE 3. Thoracic adhesive apparatus in Glyptothorax. A, G. viridis, ZSI FF 9463, holotype; B, G. ventrolineatus ZSI FF 7580, and C, G. trilineatus ZSI F 10380/1. Figures not to scale.

FIGURE 4. Glyptothorax viridis, ZSI FF 9464, 74.0 mm SL; freshly-caught specimen.

FIGURE 5. Map showing type locality of Glyptothorax viridis in the Chindwin basin, Manipur, India.