Hemibagrus maydelli ( Rössel, 1964 )

Ng, Heok Hee & Kottelat, Maurice, 2013, Revision Of The Asian Catfish Genus Hemibagrus Bleeker, 1862 (Teleostei: Siluriformes: Bagridae), Raffles Bulletin of Zoology 61 (1), pp. 205-291 : 271-274

Hemibagrus maydelli ( Rössel, 1964)

( Fig. 46 )

Mystus maydelli Rössel, 1964: 149 . Fig. 1 (type locality: Wadgaon, Bhima River); Wilkens 1977: 159; Jayaram & Sanyal, 2003: 73, Fig. 13 .

Mystus (Mystus) maydelli - Jayaram, 1966: 446.

Mystus sp. - Govind & Rajagopal, 1975: 79.

Mystus malabaricus (in part) - Jayaram. 1977: 32; Talwar & Jhingran, 1991: 564.

Mystus krishnensis Ramakrishniah, 1988: 139 , Figs. 1–2 (type locality: Krishna River below Nagarjunasagar Reservoir, India); Talwar & Jhingran, 1991: 563; Jayaram, 1995: 97, 105, 108; Jayaram, 1999: 236; Jayaram & Sanyal, 2003: 66, Fig. 10 ; Karmakar & Das, 2005: 93; Khan, 2008: 29.

Mystus punctatus (non Jerdon) - Barman, 1993: 225, Fig. 96.

Hemibagrus maydelli - Grant, 1999: 172, Fig. 2 ; Ng & Ferraris, 2000: 128, Fig. 3 ; Ferraris, 2007: 89.

Mystus menoda (non Hamilton, 1822) - Yadav, 2003: 19.

Material examined. — INDIA: ZMH 2180 , holotype, 82.0 mm SL, Maharashtra: Bhima River at Wadgaon (photograph and radiograph examined) ; ZSI FF2532 , 1 ex., 271.8 mm SL [holotype of H. krishnensis ] ; ZSI FF2533 , 1 ex., 403 mm SL [paratype of H. krishnensis ] ; ZSI FF2534 , 1 ex., 228.0 mm SL [paratype of H. krishnensis ] ; ZSI FF2535 , 1 ex., 278.8 mm SL [paratype of H. krishnensis ], Andhra Pradesh: Krishna River below Nagarjunasagar Reservoir ; CAS 62087, 2 ex., 167.2–214.7 mm SL, Karnataka: Bellary District, Krishna River drainage, Tungabahdra River and reservoir at Hospet , Hampi and Kampli .

Diagnosis. — Hemibagrus maydelli is distinguished from congeners in the H. wyckii group in having an olive green (vs. grey) body. It further differs from H. microphthalmus and H. wyckioides in having a smaller dorsal to adipose distance (4.0–7.0% SL vs. 8.6–14.2), and from H. microphthalmus in having a shorter and deeper caudal peduncle (length 15.3– 16.1% SL vs. 16.4–18.1; depth 7.8–8.5% SL vs. 6.8–7.7), a longer head (30.8–32.4% SL vs. 29.4–31.0), and H. wyckii in having a poorly ossified dorsal spine (thinner than soft dorsal-fin rays; vs. well ossified spine at least as thick as the branched dorsal-fin rays) without (vs. with 10–12) serrations on the posterior edge, an orange (vs. grey) caudal fin without (vs. with) pale procurrent rays, a smaller dorsal to adipose distance (4.0–7.0% SL vs. 7.1–11.0), a greater post-adipose distance (14.1–14.6% SL vs. 9.3–13.6), a larger eye (diameter 12% HL vs. 8–10), and a longer maxillary barbel (reaching to at least the middle of the adipose fin base; 238–299% HL vs. reaching to the middle of the dorsal-fin base; 144–195% HL).

Description. — Biometric and meristic data as in Table 30. General description as for genus. Head extremely depressed

and broad; length 30.8–32.4% SL; width 18.9–20.5% SL. Interorbital distance 29–30% HL. Eye diameter 12% HL. Body moderately compressed. Dorsal profile rising evenly but not steeply from tip of snout to origin of dorsal fin, then gently sloping ventrally to end of caudal peduncle. Ventral profile horizontal to origin of anal fin, then sloping dorsally to end of caudal peduncle. Adipose fin with moderately long base (about 1.5–2.0 times anal-fin base) and gently-sloping anterior margin. Dorsal spine thin and poorly ossified, without serrations on posterior edge. Adpressed dorsal fin reaching adipose-fin origin. Pectoral spine stout, with 13–19 serrations on posterior edge. Adipose-fin origin separated from base of last dorsal-fin ray by distance of 4.0–7.0% SL. Post-adipose distance 14.1–14.6% SL. Caudal-peduncle length 15.3–16.1% SL; caudal-peduncle depth 7.8–8.5% SL. Caudal fin forked; first principal ray of upper lobe extending into a long filament; distal margin of upper and lower lobes rounded. Maxillary barbel reaching to at least middle of adipose fin base (238–299% HL). Maximum recorded size approx. 1290 mm SL (1650 mm TL; Govind & Rajagopal, 1975).

Colour. — Preserved specimens with dorsal surface of head and body brown, gradually fading to dirty white on ventral surface. Pectoral, pelvic, anal and caudal fins brown with melanophores concentrated in interradial membranes. Dorsal fin brown with melanophores evenly distributed.

Live specimens olive green with orange-tipped fins (after Ramakrishniah, 1988).

Distribution. — Known only from the middle reaches of the Krishna River drainage in southern India ( Fig. 47).

Habitat and biology. — Hemibagrus maydelli is one of the largest species of this genus; sizes of 1650 mm TL and weights of 58 kg have been reported (Govind & Rajagopal, 1975). The Krishna River in which it occurs is fairly swift-flowing, with a sandy or pebbly bottom (Govind & Rajagopal, 1975; Jayaram, 1995).

Figures

Fig. 46. Hemibagrus maydelli, CAS 62087, 214.7 mm SL, India: Tungabahdra River.

Fig. 1. Method of measurements used in this study: 1, Standard length; 2, Predorsal length; 3, Preanal length; 4, Prepelvic length; 5, Prepectoral length; 6, Dorsal-spine length; 7, Dorsal-fin length; 8, Length of dorsal-fin base; 9, Length of anal-fin base; 10, Pelvic-fin length; 11, Pectoral-fin length; 12, Pectoral-spine length; 13, Caudal-fin length; 14, Length of adipose-fin base; 15, Maximum height of adipose fin; 16, Dorsal to adipose distance; 17, Post-adipose distance; 18, Length of caudal peduncle; 19, Depth of caudal peduncle; 20, Body depth at anus; 21, Head length; 22, Head width; 23, Head depth; 24, Snout length; 25, Interorbital distance; 26, Eye diameter.

Fig. 13. Cleithral processes of: a, H. menoda, UMMZ 208726, 202.6 mm SL; b, H. peguensis, CAS 89005, 261.9 mm SL. Scale bar = 5 mm.

Fig. 10. Map showing collection localities of Hemibagrus macropterus and H. vietnamicus specimens examined in this study

Fig.2. Hemibagrus baramensis, ZRC 42742, 150.0 mm SL; Borneo: Sarawak, Mulu.

Fig.3. Map showing collection localities ofHemibagrus baramensis specimens examined in this study.