Glyptothorax striatus McClelland 1842

Ng, Heok Hee, 2013, Glyptothorax radiolus, a new species of sisorid catfish (Osteichthyes: Siluriformes) from northeastern India, with a redescription of G. s t r i a t u s McClelland 1842, Zootaxa 3682 (4), pp. 501-512 : 506-508

Glyptothorax striatus McClelland 1842

( Fig.4 )

Material examined. BMNH 1860.3.19.95, syntype, 77.6 mm SL; India: Meghalaya, Khasi Hills. PUCMF 1058 (1), 100.8 mm SL; India: Mizoram, India: Mizoram, Tlawng River at Sairang, 23°48'36.0"N 92°39'14.4"E. PUCMF 13009 (4), 85.9–112.3 mm SL; India: Mizoram, Mamit District, Terei River (a tributary of Tlawng River) in the vicinity of Sihthiang Village, 24°2'32.4"N 92°28'0.7"E. UMMZ 245710 (1 alc., 1 c&s). 40.8–60.0 mm SL; India: West Bengal, Tista River at Tista Barrage, 26°45'10.0"N 88°34'11.0"E.

Diagnosis. Glyptothorax striatus is diagnosed from congeners in the Indian subcontinent except for G. a t e r, G. brevipinnis , G. churamanii , G. j a y a r a m i, G. nelsoni , G. pantherinus , G. pectinopterus , G. radiolus and G. saisii in having (vs. lacking) a prominently plicate ventral surface of the pectoral-fin spine and the first pelvic-fin ray. It differs from G. a t e r, G. brevipinnis , G. churamanii , G. j a y a r a m i, G. nelsoni , G. pantherinus , G. pectinopterus , G.

radiolus and G. saisii in having the following combination of characters: snout length 51.8–54.7% HL, wedgeshaped central depression in throracic adhesive apparatus devoid of skin ridges, pectoral-fin length 18.7–23.8% SL, plicae on ventral surfaces of pectoral-fin spine continuous, dorsal-fin spine length 10.3–15.7% SL, dorsal-toadipose distance 24.9–27.9% SL, body depth at anus 11.0–14.7% SL, adipose-fin base length 10.7–13.5% SL, caudal-peduncle length 18.4–20.7% SL, caudal-peduncle depth 6.8–8.6% SL (1.6–1.9 times in body depth at anus), and distinct pale midlateral stripe on body.

Description. Morphometric data as in Table 2 . Head depressed, body subcylindrical. Dorsal profile rising evenly from tip of snout to origin of dorsal fin, sloping gently ventrally from origin of dorsal fin to end of caudal peduncle. Ventral profile flat to anal-fin base, sloping gently dorsally from anal-fin base to end of caudal peduncle. Anus and urogenital openings located at vertical through middle of adpressed pelvic fin. Caudal peduncle long and thin, depth 1.6–1.9 times in body depth at anus. Skin almost smooth, with minute tubercles on sides of body. Lateral line complete, mid-lateral. Vertebrae 18+18=36 (1), 19+18=37 (4) or 20+17=37 (1).

Head depressed, broad; triangular in lateral view. Snout prominent. Anterior and posterior nares large, separated only by base of nasal barbel. Gill openings broad, extending from immediately ventral to post-temporal to isthmus. Bony elements of dorsal surface of head covered with thick, tuberculate skin. Eye ovoid, its horizontal axis longest; located entirely in dorsal half of head.

Barbels in four pairs. Maxillary barbel long slender; extending to middle of pectoral-fin base. Nasal barbel slender, extending to midway between its base and anterior orbital margin. Inner mandibular-barbel origin close to midline, extending to midway between its base and that of pectoral spine. Outer mandibular barbel originating posterolateral of inner mandibular barbel, extending to base of pectoral spine.

Mouth inferior, premaxillary tooth band not exposed with mouth closed. Oral teeth small, villiform; in irregular rows on all tooth-bearing surfaces. Premaxillary teeth in a single broad semilunate band. Dentary teeth in two narrow crescentic bands separated at midline.

Thoracic adhesive apparatus present, consisting of ridges of skin (plicae) in rhomboidal field extending from isthmus to level of middle of pectoral-fin base, with wedge-shaped median depression on posterior half open caudally. Plicae uninterrupted; medial plicae orientated anteriorly, lateral ones anterolaterally.

Pectoral fin with I,9,i (6) rays; posterior fin margin slightly concave. Pectoral spine very broad and covered with thick skin. Anterior spine margin smooth, its posterior margin with 8–10 serrae. Ventral surface of spine with prominent plicae. Dorsal fin above anterior third of body, with I,6 (6) rays; fin margin convex; spine broad, straight; with smooth posterior margin. Vertical through pelvic-fin origin posterior to that through posterior end of dorsal-fin base. Pelvic fin with slightly convex margin and i,5 (6) rays, ventral surface of first ray with prominent plicae; tip of adpressed fin not reaching anal-fin origin. Adipose fin with anterior margin straight or very slightly concave, posterior margin angular. Vertical through anal-fin origin posterior to that through adipose-fin origin. Anal fin with straight anterior margin, straight or slightly concave posterior margin; with iii,9 (3) or iv,9 (3) rays. Caudal fin strongly forked, with lower lobe very slightly longer than upper lobe and i,7,8,i (6) principal rays. Procurrent rays symmetrical, extending only slightly anterior to fin base.

Coloration. In 70% alcohol: dorsal and lateral surfaces of head and body dark brown, fading to light grayish brown light grayish brown on ventral surfaces and fading to slightly paler brown at tip of caudal peduncle in some individuals. Distinct pale mid-dorsal stripe on dorsal surface of body and midlateral stripe running along entire length of body. Dorsal, pectoral, pelvic and anal fins also dark brown, particularly on rays. Adipose fin dark brown basally, fading to lighter brown along distal margin. Caudal fin brown, with scatterd dark brown spots and hyaline margins at tips of fin lobes. Nasal and maxillary barbels dark brown dorsally, light grayish brown ventrally; all mandibular barbels light grayish brown. Life coloration similar, with darker body coloration and more prominent pale mid-dorsal and midlateral stripes.

Distribution. Known from both the Brahmaputra River drainage and the Surma-Meghna River system in India ( Fig. 3 ).

Figures

FIGURE 3. Map showing collecting localities of Glyptothorax radiolus (triangle) and G. striatus (circles).

FIGURE 4. Glyptothorax striatus, PUCMF 1058, 100.8 mm SL; dorsal, lateral and ventral views.

Tables

TABLE 2. Biometric data for Glyptothorax striatus (n = 7).

Standard length (mm) Percent of standard length Predorsal length Preanal length Prepelvic length	Syntype Range BMNH 1860.3.19.95 77.6 40.8–112.3 35.1 32.8–36.6 67.8 65.0–67.9 47.3 46.3–47.5	Mean±SD 35.0±1.22 66.6±1.15 47.0±0.51
Prepectoral length Dorsal-fin base length	20 17.9–21.7 12.5 11.5–15.9	19.2±1.27 13.3±1.40
Dorsal-spine length Anal-fin base length Pelvic-fin length Pectoral-fin length	13.1 10.3–15.7 13.4 12.8–16.1 18.8 161–18.8 22.7 18.7–23.8	12.8±1.88 14.7±1.19 17.5±1.02 21.7±1.66
Pectoral-spine length Caudal-fin length	16.9 12.5–16.9 25.5 24.9–27.8	14.2±1.76 25.8±1.01
Adipose-fin base length Dorsal-to-adipose distance Post-adipose distance Caudal-peduncle length	12.9 10.7–13.5 26.0 24.9–27.9 16.5 16.5–21.1 19.2 18.4–20.7	12.4±1.10 26.0±0.92 19.3±1.62 19.7±0.72
Caudal-peduncle depth Body depth at anus	7.2 6.8–8.6 11.7 11.0–14.7	7.8±0.67 13.2±1.49
Head length Head width Head depth Percent of head length Snout length Interorbital distance	24.7 23.8–27.6 20.2 19.4–20.9 11.0 11.0–14.4 52.6 51.8–54.7 33.3 25.2–33.3	25.0±1.28 20.4±0.51 13.2±1.40 52.9±1.03 29.4±2.41
Eye diameter Nasal barbel length Maxillary barbel length Inner mandibular barbel length Outer mandibular barbel length	7.4 8.7–11.5 25.5 13.8–29.4 97.4 72.4–104.4 24.5 21.1–36.2 46.4 39.8–60.5	9.7±0.90 24.0±5.23 91.6±11.42 30.6±5.66 51.6±6.83