Sisor rabdophorus Hamilton, 1822

Ng, H. H., 2003, A revision of the south Asian sisorid catfish genus Sisor (Teleostei: Siluriformes), Journal of Natural History 37 (23), pp. 2871-2883 : 2873-2876

Sisor rabdophorus Hamilton, 1822

(figures 2b, 3, 4b)

Sisor rabdophorus Hamilton, 1822: 208 (type locality: rivers of Bengal and Bihar).

Sisor rhabdophorus: Valenciennes , in Cuvier and Valenciennes, 1840: 450; Bleeker, 1853: 60; Günther, 1864: 262; Beavan, 1877: 150; Day, 1877: 491, pl. 115, figures 1, 1a, b (in part); Day, 1889: 105, figure 43 (in part); Shaw and Shebbeare, 1937: 107, figure 111; Jayaram and Singh, 1977: 268; Misra, 1976: 312, figure 54 (in part); Menon, 1977: 83 (in part); Talwar and Jhingran, 1991: 681, figure 217 (in part); Sen, 1992: 202; Jayaram, 1999: 301 (in part); Menon, 1999: 234 (in part); Tekriwal and Rao, 1999: 109; Karmakar, 2000: 34 (in part).

Material examined

N  . ZRC 45829, 65.6 mm SL; India: West Bengal State, Bhagirathi River at crossing point between Kalna (Barddhaman District) and Nisinghapur ( Nadia District ) (23 ° 13 ∞ 33 ◊ N, 88 ° 32 ∞ 41.4 ◊ E); H. H. Ng and D. C. J. Yeo, 22 January 1999 .

Other material. ZRC 45830, six specimens, 46.8–59.0 mm SL; data as for neotype. CMK 15110, three specimens, 65.1–72.1 mm SL ; UMMZ 240013 , two specimens, 63.8–77.6 mm SL ; ZRC 45831, 10 specimens, 63.2–90.3 mm SL; India: West Bengal State, Bhagirathi River , from aquarium trade .

Diagnosis

Sisor rabdophorus has fewer lateral line ossicles (66–70 vs 72–79) and serrations on the anterior (27–29 vs 29–49) and posterior (6–15 vs 12–22) edges of the pectoral spine compared to the other species. It further differs from S. chennuah and S. torosus in having a more slender body (body depth at anus 5.0–5.4% SL vs 5.6–7.8), and

from S. rheophilus in having a smaller eye (9.4–12.2% HL vs 13.2–16.3) and a shorter snout (53.9–55.7% HL vs 56.2–60.3).

Description

General appearance as for genus. In % SL: body depth at anus 5.0–5.4, predorsal length 28.5–35.2, preanal length 60.0–67.2, prepelvic length 32.1–35.9, prepectoral length 15.3–18.5, length of dorsal-fin base 11.8–13.5, length of dorsal spine 9.0–10.1, length of anal-fin base 7.2–8.7, length of pelvic fin 14.2–17.4, length of pectoral fin 20.1–23.5, length of pectoral spine 17.1–19.3, depth of caudal peduncle 1.6–2.0, length of caudal peduncle 22.9–26.4, length of caudal fin 12.3–15.5, head length 19.1–22.6, head width 15.1–17.7, head depth 8.2–9.4; in % HL: snout length 53.9–55.7, interorbital distance 20.6–22.8, eye diameter 9.4–12.2, length of maxillary barbel 59.0–73.9, length of inner mandibular barbel 42.7–54.0, length of outer mandibular barbel 42.2–63.9. Branchiostegal rays five (2) or six (4). Vertebrae 20 + 12 = 32 (1), 20 + 13 = 33, 21 + 13 = 34 (2) or 22 + 13 = 35 (1). Lateral line ossicles 66–70. Nuchal plate with a short, narrow central process, width 1.2–1.3 times length (figure 2b).

Fin-ray counts: dorsal I, 6 (6); pectoral I, 10 (2), I, 10, i (3) or I, 11 (1); pelvic i, 5 (2), i, 6 (2) or i, 7 (2); anal ii, 4 (6); caudal 5/6 (5) or 5/7 (1). Anterior edge of pectoral spine with 27–29 long and narrow serrations on anterior edge, and 6–15 smaller, more recurved serrations on posterior edge (figure 4b).

Distribution Known from the lower Ganges River drainage in West Bengal State, India.