Glyptothorax rupiri, Kosygin & Singh & Rath, 2021

Kosygin, Laishram, Singh, Pratima & Rath, Shibananda, 2021, A new species of Glyptothorax (Teleostei: Sisoridae) from the Brahmaputra River basin, Arunachal Pradesh, India, Zootaxa 5023 (2), pp. 239-250 : 240-242

Glyptothorax rupiri , new species

( Fig. 1 )

urn:lsid:zoobank.org:act:832DD37C-BFEB-4A77-9584-980B6E6D5F12

Type material. Holotype: ZSI FF 8542, 124 mm SL, India: Arunachal Pradesh: Upper Siang District: Jambung stream, a tributary of Siang River near Hawa Camp ( Brahmaputra River basin), 28°41′9.2″ N; 94°58′8.82″E, 28 October 2017, collected by L Kosygin.

Paratypes: ZSI FF 8543, 3 ex. 156 –161 mm SL, same data as holotype .

Diagnosis. Glyptothorax rupiri is distinguished from congeners in the Indian subcontinent in possessing the following combination of characters: the presence of plicae on the ventral surface of the pectoral-fin spine and first pelvic-fin ray; body depth at anus 11.2–13.4% SL; a posteriorly serrated dorsal-fin spine, its length 11.3–12.2% SL; a thoracic adhesive apparatus, longer than broad, with a V-shaped median depression which opens posteriorly; an arrowshaped anterior nuchal plate element; adipose-fin base length 10.9–12.6% SL; dorsal-to-adipose distance 26.1–27.8% SL; post-adipose distance 17.7–19.7% SL; caudal peduncle depth 6.4–7.5% SL; 14–18 serrae on posterior margin of the pectoral-fin spine; unculiferous ridges of adhesive apparatus not extending anteriorly onto gular region; nasal barbel not reaching anterior orbital margin; body with two longitudinal pale-cream stripes; densely tuberculated skin; and the presence of numerous tubercles on the dorsal surface of pectoral and pelvic-fin rays.

Description. Morphometric data are presented in Table 1. Body elongate. Head depressed with almost rounded snout when viewed dorsally and ventrally. Dorsal profile rising evenly from tip of snout to origin of dorsal-fin, then sloping gently from there to end of caudal peduncle, with slight rising at adipose-fin origin. 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 origin of anal-fin base, then rising along anal-fin base, thereafter level up to end of caudal-fin base. Caudal peduncle shallow. Mouth inferior, lips papillate, teeth on upper jaw as one continuous band, its anterior margin almost truncate or slightly rounded; teeth on lower jaw in two patches, separated by a wide median partition. Eyes small, round, located on dorsal surface of head. Thoracic adhesive apparatus elliptical, longer than broad, extending from isthmus to slightly before posterior end of pectoralfin base, with an inverted V-shaped median depression on posterior half, opening caudally; ridges of apparatus not reaching gular region ( Fig. 2 ). Anus and urogenital opening located at tip of adpressed pelvic fin. Skin on head and body densely tuberculated. Lateral line complete, mid-lateral. Vertebrae 21 + 20 = 41 or 21 + 21 = 42.

Barbels in four pairs. Maxillary barbel long, slender, reaching middle of pectoral-fin base. Outer mandibular barbel longer than inner, almost reaching gill opening. Nasal barbel short, not reaching anterior margin of orbit when adpressed.

Dorsal fin with i,6 (4) rays, its origin located slightly nearer adipose-fin origin than snout tip; dosal-fin spine strong, shorter than depth of body, anterior margin smooth, posterior margin with 9–11 serrae. Adipose-fin short, its origin slightly posterior to anal-fin origin, anterior margin straight, posterior margin slightly convex. Pectoral fin slightly shorter than head, with i,10 (3) or i,10,i (1) rays; its posterior margin almost straight or slightly concave. Pectoral-fin spine broad, long, its anterior margin smooth, posterior margin with 14–18 serrae. Pelvic fin with i,5 (4) rays, its tip not reaching origin of anal fin when adpressed. Ventral surface of pectoral-fin spine ( Fig. 2 ) and first pelvic-fin ray plaited. Dorsal surface of pectoral and pelvic fins tuberculated ( Fig. 3 ). Anal fin long, with ii,10 (4) rays; its origin slightly anterior to adipose fin origin. Caudal fin deeply forked, lower lobe slightly longer, with 8+9 (3) or 7+7 (1) rays.

Coloration. In 70 % alcohol: Dorsal surface of the head and body dark brown, lateral surface dark brown fading to yellowish cream ventrally. Nuchal plate elements visible as a distinct, pale, arrow-shaped saddle overlying plate elements. Two pale creamish longitudinal stripes: one prominent, middorsal, originating from the occiput, other indistinct, midlateral, originating from eye, extending to caudal-fin base ( Fig. 1 ). Dorsal-fin base black. Adipose fin dark brown with creamish posterior margin. Caudal, pectoral, pelvic and anal fins dusky.

Distribution. The species is presently known only from the type locality, the Jambung stream, a tributary of the Siang River near Hawa Camp, Upper Siang District, Arunachal Pradesh (Brahmaputra River basin), India ( Figs. 4 & 5 ).

Etymology. The species is named after Rupir Boli of the Forest Department, Government of Arunachal Pradesh, for his help in collecting the specimens during the first author’s survey of Arunachal Pradesh.

Figures

FIGURE 1. Glyptothorax rupiri, ZSI FF 8542, holotype, 124 mm SL: a, dorsal; b, lateral; and c, ventral aspects.

FIGURE 2. Thoracic adhesive apparatus and ventral surface of pectoral-fin, showing plicae, of Glyptothorax rupiri, ZSI FF 8543, Paratype, 161 mm SL.

FIGURE 3. Tuberculation on dorsal surface of paired fins of Glyptothorax rupiri, ZSI FF 8542, holotype, 124 mm SL: a, pectoral-fin; b, pelvic-fin.

FIGURE 4. Map showing collection localities of Glyptothorax rupiri (Jambung stream, a tributary of Siang River near Hawa Camp, Brahmaputra River basin, India).

FIGURE 5. Jambung stream a tributary of Siang River near Hawa Camp, type locality of Glyptothorax rupiri.