Hemibagrus caveatus Ng, Wirjoatmodjo & Hadiaty, 2001

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 : 225-227

Hemibagrus caveatus Ng, Wirjoatmodjo & Hadiaty, 2001

( Fig. 16 )

Hemibagrus caveatus Ng, Wirjoatmodjo & Hadiaty, 2001: 359 , Fig. 1 (type locality: Sungai Soraya, a tributary of Sungai Alas, Aceh Province, Sumatra); Hadiaty, 2005: 382; Ferraris, 2007: 87.

Material examined. — SUMATRA: Nangroe Aceh Darussalam : MZB 8714 , holotype, 186.3 mm SL, Sungai Soraya, a tributary of

Sungai Alas; MZB 5625 , 1 paratype, 195.5 mm SL, Sungai Alas ; MZB 5664 , 1 paratype, 130.4 mm SL, Sumatra: Aceh, Sungai Alas, 5 km upstream of Gelombang ; MZB 8708 , 1 paratype, 130.7 mm SL, Sungai Sembelin, a tributary of Sungai Alas . ZRC 51968, 1 ex., 51.7 mm SL; Trumon, hillstream along Subulussalam–Singkil road, 2°53'8.2"N 97°41'25.7"E .

Diagnosis. — Hemibagrus caveatus differs from all other members of the H. menoda species group in having thin vertical lines and a midlateral line (vs. dark spots arranged in vertical columns) along the sides of the body. It further differs from both H. menoda and H. peguensis in having a larger eye (14–16% HL vs. 11–14), and from H. menoda in having a longer caudal peduncle (17.6–19.1% SL vs. 15.2–17.0), and deeper adipose fin (maximum height of adipose fin 5.3–6.2% SL vs. 3.8–4.5).

Description. — Biometric and meristic data as in Table 8. General description as for genus. Head depressed and broad,

body moderately compressed. Head length 29.7–30.9% SL; head depth 15.8–17.2% SL. Snout rounded. Eye diameter 14–16% 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 17.6–19.1% SL; caudal-peduncle depth 8.4–9.5% SL. Cleithral process narrow, notched for about one third its maximum width. Adipose-fin base short, approximately as long as anal-fin base (12.7–16.1% SL); maximum height 5.3–6.2% SL. Adipose-fin origin separated from base of last dorsal-fin ray by distance of 10.0–17.7% SL. Dorsal spine stout, with 5–8 serrations on posterior edge. Pectoral spine stout, with 12–17 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 196 mm SL.

Colour. — Preserved specimens with dorsal surface of head and body grey, gradually fading to dirty white on ventral surface. Lateral surface of body with 11–13 dark vertical lines and dark horizontal line running along lateral line. Dorsal, pectoral, pelvic and anal fins grey, with scattered melanophores on fin rays and interradial membranes. Caudal fin grey, with lighter hue along posterior edge, and on procurrent and outer principal caudal rays. Colour in life similar, except for more greenish tone on body and orangeish/reddish anal and caudal fins.

Distribution. — Hemibagrus caveatus is known only from the Alas River drainage in northern Sumatra ( Fig. 17 ).

Remarks. — Hemibagrus caveatus is placed within the H. menoda species group on account of its colour pattern (which is unique among Southeast Asian species).

Figures

Fig. 16.Hemibagrus caveatus, ZRC 51968, 51.7 mm SL; Sumatra: Trumon.

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