Glyptothorax churamanii, Rameshori & Vishwanath, 2012

Rameshori, Yumnam & Vishwanath, Waikhom, 2012, A new catfish of the genus Glyptothorax from the Kaladan basin, Northeast India (Teleostei: Sisoridae), Zootaxa 3538, pp. 79-87 : 80-84

Glyptothorax churamanii , new species

( Fig. 1)

Type material. Holotype: MUMF 14023 , 85.5 mm SL; India: Mizoram: Lawntlai: Kaladan River at Kolchaw , 22°23'N 92°57'E; Lokeshwor et al., April 2011.

Paratypes: MUMF 14024–14026 , 62.5–83.9 mm SL; same data as holotype; one paratype ( MUMF 14025 , 78.8 mm SL), dissected for osteology .

Diagnosis. Glyptothorax churamanii can be distinguished from the congeners of NE Indian region in having the combination of characters: an oblong thoracic adhesive apparatus with an inverted V-shaped median depression on the posterior half, opening caudally, ridges of the apparatus not reaching the gular region; the occipital process not reaching the anterior nuchal-plate element; a slightly longer ventral lobe than dorsal lobe of the caudal fin, with diffused black submarginal bands on each lobe; sparsely tuberculate skin; pleated ventral surfaces of pectoral spine and upto two outer rays of pelvic fins, plicae on pectoral spine arranged in rows, continuous distally and dissociated in a series of three to five hexagonal-shaped spots in each row; 3+10 gill rakers on the first branchial arch; length of dorsal-fin base (12.0–13.9% SL); length of caudal fin (25.1–27.6% SL).

Description. Morphometric data as in Table 1. Body elongate, sub-cylindrical. Dorsal profile rising evenly from snout tip till first dorsal-fin pterygiophore, then sloping gradually posteroventrally from end of dorsal-fin base towards caudal-fin base. Occipital process not in contact with anterior nuchal plate element. Ventral profile flat till posterior end of pelvic-fin base, then sloping gently dorsad to end of caudal-fin base. Anus and urogenital openings located two-thirds distance away from posterior pelvic-fin base towards anterior anal-fin base. Skin on head and body with sparse tuberculations. Lateral line complete, midlateral. Vertebrae 19+19. First branchial arch with 3+10(4) gill rakers.

Head depressed, slightly longer than broad, triangular when viewed laterally. Snout prominent, convex dorsally. Anterior and posterior nares separated only by base of nasal barbel. Eyes small, rounded, placed anterodorsally at middle of head length. Gill openings wide extending from beneath post-temporal to isthmus.

Barbels in four pairs. Maxillary barbel long, its base broad, thick, reaching anterior base of pectoral fin. Nasal barbel slender, originating from internarial septum, extending half way between its base and anterior orbital margin. Inner mandibular barbel extending till isthmus. Outer mandibular barbel originating posterolateral to inner mandibular barbel, with broad base, reaching anterior base of pectoral spine, longer than inner mandibular barbel.

Mouth inferior, lips broad, papillated, upper jaw longer than lower, premaxillary tooth band exposed partially with mouth closed. Oral teeth small, villiform borne on all tooth-bearing surfaces, palate edentate. Premaxillary teeth arranged in single broad semilunate band. Dentary teeth in two crescentic patches separated at midline by narrow gap.

Dorsal fin located nearer to snout tip than to caudal-fin base, with I,5,i rays, its distal and posterior margins straight. Dorsal spine long, strong, its anterior margin smooth, posterior margin serrated with 4–5 small serrae. Adipose fin with slightly concave anterior and posterior margins, distal part of fin slightly convex. Anal fin with iv,9 rays, posterior and distal margins straight, located slightly anterior to adipose-fin origin. Caudal fin with i,7,8,i rays, forked, ventral lobe slightly longer than dorsal lobe. Procurrent rays symmetrical, extending to caudal-fin base. Pectoral fin with gently convex anterior margin, straight distal and slightly concave posterior margins, with I,9,i rays. Pectoral spine covered with thick skin, anterior margin smooth, posterior serrated with 13–14 serrae, spine strong for two-third proximal length, soft distally, ventral surface with plicae arranged in rows, continuous distally, dissociated in series of 3–5 hexagonal spots in each row ( Fig. 2a). Pelvic fin with I,5 rays, origin at vertical through posterior end of last dorsal-fin rays, anterior margin convex, distal margin straight. Tip of adpressed pelvic fin reaching anus and urinogenital opening, falling short of anterior anal-fin base. Ventral surfaces of first (and sometimes second) pelvic-fin rays with plicae ( Fig. 2b).

Thoracic adhesive apparatus with median depression present; ridges of apparatus diverging anterolaterally from inverted V-shaped median depression on posterior half, forming oblong field extending from isthmus to twothirds length of pectoral-fin base, opening caudally ( Fig. 3). Apparatus not reaching gular region.

Coloration. In 10% formalin: dorsal and lateral surfaces of head and body amber. Ventral surfaces of head and body yellowish-cream color. Laterosensory line along lateral line light yellowish-cream against amber. Dorsal fin amber; fin rays with scattered melanophores. Adipose fin amber with light gray distal margin. Pectoral, pelvic and anal fins yellowish cream with amber fin bases, fin rays with scattered melanophores. Caudal fin with diffused black submarginal bands on each lobe against amber background, distal margin hyaline; procurrent rays with scattered melanophores.

Distribution. Known from the Kaladan River at Kolchaw, Mizoram state, Northeastern India ( Fig. 4).

Etymology. The species is named after Churamani, who has rendered immense help in the collection of the fish.