Hemibagrus vietnamicus Mai, 1978

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 : 221-224

Hemibagrus vietnamicus Mai, 1978

( Fig. 11 )

Hemibagrus vietnamicus Mai, 1978: 252 , Fig. 116 (type locality: north Vietnam); Mai, 1985: 284; Kottelat, 2001a: 51, Fig. 104; Ferraris, 2007: 91.

Macrones chinensis (non Steindachner, 1883) - Chevey & Lemasson, 1937: 113, Pl. 34, Fig. 77; Le Poulain, 1945: 68.

Mystus chinensis (non Steindachner, 1883) - Kuronuma, 1961: 6; Orsi, 1974: 161.

Mystus guttatus (non La Cepède, 1803) - Chu, 1986: 130, Fig. 86.

Hemibagrus guttatus (non La Cepède, 1803) - Kottelat, 2001b: 122, Fig. 328.

Hemibagrus camthuyensis Nguy n, 2005: 632, Fig. 49 (type locality: Ma River , Cam Thuy district, Thanh Hoa province, Vietnam).

Material examined. — VIETNAM: ZMUH 260 , 12 syntypes, 121.1–259.3 mm SL ; ZMUH 250 , 15 syntypes, 58.1–221.0 mm SL, northern Vietnam ; AMNH 230998 , 2 ex., 152.1–182.2 mm SL, Quang Nam province: Tam Ky district, Nuoc Ta River , at ferry ; CAS 95031, 3 ex., 127.3–163.3 mm SL, Hoa Binh market ; UMMZ 238764 , 3 ex., 67.0–138.0 mm SL; Nghe Anh province: market in Anh Son ; ZRC 42552, 4 ex., 560–700 mm SL, market in Hanoi ( Cho Hang Da ) ; ZRC 42553, 2 ex., 450–495 mm SL, market in Hanoi ( Cho Hang Be ) .

LAOS: CMK 15338, 2 ex., 154.5–208.6 mm SL, Houaphan province: Nam Xam in Ban Sopkhem ; CMK 15391, 1 ex., 179.7 mm SL, Houaphan province: Nam Ma at Xiang Kho .

Diagnosis. — Hemibagrus vietnamicus differs from H. macropterus in having a double-chambered (vs. singlechambered) swim bladder, the adipose fin not confluent (vs. partially confluent) with the principal rays of the caudal fin, and a grey (vs. brown) body, and from H. guttatus in having a shorter pectoral spine (extending to a vertical through the base of the dorsal spine vs. beyond a vertical through the base of the dorsal spine) and more vertebrae (58–59 vs. 51–54).

Description. — Biometric and meristic data as in Table 6. General description as for genus. Head depressed and broad, body moderately compressed. 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. Adipose-fin base very long, spanning almost all of postdorsal distance, about 3.0 times length of anal-fin base, not confluent with principal rays of caudal fin. Dorsal spine stout, with 4–14 serrations on posterior edge. Pectoral spine stout, with 10–17 large serrations on posterior edge, extending to a vertical through base of dorsal spine. Anal-fin origin posterior to adipose origin. Adpressed dorsal fin reaching adipose fin. Caudal fin forked; upper and lower lobes rounded. Swim bladder with two chambers. Vertebrae 58–59. Maximum recorded size approx. 850 mm SL.

Colour. — Dorsal surface of head and body uniform light grey to grey (live or freshly-dead specimens with slight yellow hue, fading on preservation); few small dark grey spots one quarter eye diameter or larger on side of body, located posterior to origin of adipose fin, caudal fin with few such spots occasionally present; ventral surface of head and body dirty white; adipose fin and fin rays of all fins grey; inter-radial membranes of all fins hyaline.

Distribution. — Hemigrammus vietnamicus is presently only known from the Song Hong (Red River) drainage in northern Vietnam, the Song Ca (also known as the Song Lam) drainage in northern Vietnam and northern Laos and the Song Quan drainage in central Vietnam ( Fig. 10 ). Its range possibly extends to the drainages in north central Vietnam beween the Song Ca and Song Quan drainages. It is likely that records of H. guttatus from the Yuanjiang (Chinese portion of the Red River) drainage (e.g. Cui, 1990) may refer to this species, but we were unable to examine any material from China to verify if this is the case.

Remarks. — The figures given in Mai (1978) of the north Vietnamese Hemibagrus suffer from a serious layout problem ( Kottelat, 1989) in which many were misplaced with respect to the captions. Although all the figures with their ostensibly correct numbers and legends have been printed again at the end of the book on 48 separately-numbered pages, two of the figures of the Hemibagrus species are still not labelled accurately: the figures of H. centralus and H. vietnamicus (misspelled as H. vietnammicus in the figure legend; see Kottelat et al., 1998) have been transposed with respect to the captions (Mai Dinh Yen, pers. comm. to NHH), which explains the conclusion by Kottelat et al. (1998) that H. centralus resembles H. guttatus and H. vietnamicus resembles H. pluriradiatus . Figure 115 of the erratum in Mai (1978) shows H. centralus and Fig. 116 shows H. vietnamicus .

Hemibagrus camthuyensis is described from the Ma River (Song Ma) drainage in northern Vietnam. This species is said to be distinguished from H. guttatus (which is superficially very similar to H. vietnamicus ) in having thicker lips, nonoverlapping branchiostegal membranes, palatal teeth strongly curved and maxillary barbels reaching the base of the anal fin. Based on our examination of the data in the original description and examination of material from the Song Ma in Laos, we were unable to find significant differences between H. camthuyensis and H. vietnamicus , and conclude that they are conspecific.

Figures

Fig. 11. Hemibagrus vietnamicus, CMK 15391, 179.7 mm SL; Laos: Nam Ma.

Fig. 49. Map showing collection localities of Hemibagrus microphthalmus and H. wyckioides specimens examined in this study.

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