Hemibagrus peguensis ( Boulenger, 1894 )

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 : 227-228

Hemibagrus peguensis ( Boulenger, 1894)

( Fig. 18 )

Macrones peguensis Boulenger, 1894: 196 (type locality: Sittang River near Toungoo, Myanmar).

Bagrus menoda (non Hamilton, 1822) - Blyth, 1860: 285.

Macrones menoda (non Hamilton, 1822) - Day, 1871: 706 (in part); Vinciguerra, 1890: 223.

Macrones corsula (non Hamilton, 1822) - Anderson, 1879: 863; Kyaw Win, 1971: 53, Fig. 21 .

Mystus (Mystus) menoda (in part) - Jayaram, 1954: 546; Misra, 1976: 95.

Mystus (Mystus) peguensis - Jayaram, 1954: 552; 1966: 446; Misra, 1976: 100.

Mystus menoda menoda (in part) - Jayaram, 1977: 33.

Mystus peguensis - Jayaram, 1977: 35; Talwar & Jhingran, 1991: 569; Jayaram & Sanyal, 2003: 92, Fig. 19 ; Khan, 2008: 35.

Hemibagrus peguensis - Mo, 1991: 132; Ng & Ferraris, 2000: 136, Fig. 10 ; Vishwanath et al., 2007: 137; Ferraris, 2007: 90; Mahanta et al., 2011: 348.

Mystus menoda (in part) - Jayaram, 1999: 236; Jayaram & Sanyal, 2003: 75 (in part).

Material examined. — MYANMAR: BMNH 1894.5.21:25–26, 2 syntypes, 168.8–185.1 mm SL, Taungoo ; NRM 31068, 1 ex., 186.1 mm SL, Kachin state, Irrawaddy River drainage, Myitkyina ; NRM 15064, 2 ex., 116.8–138.9 mm SL, Sagaing division, Irrawaddy River drainage, Shweli River ; CAS 93201, 1 ex., 148.0 mm SL, Irrawaddy River drainage, Mandalay markets; NRM 15105, 1 ex., 166.8 mm SL, Mandalay division, Mandalay; ZRC 43707–43709 , 3 ex., 176.1–189.7 mm SL; Irrawaddy River; CAS 133789 , 1 ex., 212.7 mm SL, Yangon division, Bago River drainage, 9 miles NW of Hlegu ; NRM 39397, 1 ex., 290.6 mm SL, Bago division, Bago; ZRC 43511, 1 ex., 243.3 mm SL, Yangon division, Win Paw Hta River , near border between Bago & Yangon divisions; BMNH 1891.11.30:200–209, 16 ex., 168.7–285.6 mm SL, Sittoung (Sittaung) River ; CAS 89005, 1 ex., 261.9 mm SL, Bago division, Sittaung River at Taungoo ; ZSI 550 , 1 ex., 241.2 mm SL , ZSI 551 , 1 ex., 265.6 mm SL, Tagoung .

Diagnosis. — Hemibagrus peguensis differs from H. caveatus in having a pattern of dark spots arranged in vertical columns (vs. thin vertical lines and a midlateral line) along the sides of the body. It is distinguished from H. menoda in having an almost truncate (vs. rounded) snout ( Fig. 12 ) and a narrower, more deeply notched cleithral process (for about one third its maximum width vs. about one quarter its maximum width; Fig. 13 ), and from H. punctatus in having a longer adiposefin base (14.2–19.3% SL vs. 10.1–13.2) and a smaller eye (11–14% HL vs. 14–16).

Description. — Biometric and meristic data as in Table 9. General description as for genus. Head depressed and broad, body moderately compressed. Head length 29.0–32.5% SL; head depth 12.9–15.2% SL. Snout almost truncate. Eye diameter 11–14% HL. Dorsal profile rising evenly but not steeply from tip of snout to origin of dorsal fin, then sloping gently ventrally from there to end of caudal peduncle. Ventral profile horizontal to origin of anal fin, then sloping dorsally to end of caudal peduncle. Caudal-peduncle length 16.2–18.2% SL; caudal-peduncle depth 7.6–8.8% SL. Cleithral process narrow, notched for about one third its maximum width. Adipose-fin base short, approximately as long as anal-fin base (14.2–19.3% SL); maximum height 3.7–4.9% SL. Adipose-fin origin separated from base of last dorsal-fin ray by distance of 10.4–15.0% SL. Dorsal spine stout, with 6–11 serrations on posterior edge. Pectoral spine stout, with 15–19 serrations on posterior edge. Anal-fin origin slightly posterior to adipose origin. Adpressed dorsal not reaching adipose fin. Caudal fin forked; distal margins of upper and lower lobes rounded. Maximum recorded size 286 mm SL.

Colour. — Preserved specimens with dorsal surface of head and body greyish brown, gradually fading to dirty white on ventral surface. Lateral surface of body with about nine vertical columns of black spots, largest spots being those in middle of columns, along lateral line. Dorsal, pectoral, pelvic and anal fins greyish brown, with scattered melanophores on fin rays and interradial membranes. Caudal fin greyish brown, with lighter hue along posterior edge, and on procurrent and outer principal caudal rays.

Distribution. — Hemibagrus peguensis is known from the Irrawaddy, Bago and Sittang river drainages in Myanmar ( Fig. 17 ).

Remarks. — Hemibagrus peguensis has long been misidentified as H. menoda (e.g. Day, 1889; Jayaram, 1954). Even in cases where it was considered a distinct species (e.g. Jayaram, 1977; Talwar & Jhingran, 1991; Jayaram & Sanyal, 2003), no clear distinguishing character was used to separate the two species, nor was it recognised that H. peguensis superficially resembled H. menoda . As a result, these accounts often listed the presence of H. menoda in Myanmar when in fact the records actually refer to H. peguensis . The original description of H. peguensis gives the total lengths of the syntypes as 20 mm. This is most probably a typographical error for 200 mm (the approximate total lengths of the syntypes).

Figures

Fig. 18. Hemibagrus peguensis, ZRC 43708, 177.8 mm SL; Myanmar: Irrawaddy River.

Fig. 21. Hemibagrus nemurus, ZRC 42564, 238.6 mm SL, Java: Sungai Sokan.

Fig. 19. a, Hemibagrus punctatus, ZSI FF 1223, 193.1 mm SL; India: Hemavathy River; b, Specimen (not preserved) from Cauvery River, Karnataka (approx. 250 mm SL) showing live colouration. (Photograph courtesy of Johnny Jensen; copyright www.jjphoto.

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

Fig. 12. Dorsal views of heads of: a, H. menoda, UMMZ 208726, 202.6 mm SL; b, H. peguensis, CAS 133789, 212.7 mm SL. Scale bar = 10 mm.

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. 17. Map showing collection localities of Hemibagrus caveatus and H. peguensis specimens examined in this study