Hampala lupar, Hui & Grinang & Jongkar, 2025

Hampala lupar , new species

( Figs. 1–3)

Hampala bimaculata View in CoL (non-Popta) – Cramphorn, 1982: 26, 28, 31; Doi & Taki, 1994: 411 (part), fig. 2 (NHM 1983.6.20:4); Kottelat & Lim, 1995: 230 (part); Abdullah, 2004: 20 (Table of fish recorded from Batang Ai National Park).

Hampala bimaculata View in CoL ( 3 spots) – Cramphorn, 1982: 29. Holotype. ZRC 60435, 147.2 mm SL; East Malaysia: Sarawak: Sri Aman Division : Lupar basin; Sungei Engkari mainstream, ca. 500 m – 1 km downstream of Nanga Segerak Field Station; 01°24.881′N 111°59.960′E, 388 m asl; colls. Tan HH et al, 23 September 2018. GoogleMaps

Paratypes. ZRC 60452 View Materials , 1 ex., 42.9 mm SL; East Malaysia: Sarawak: Sri Aman Division : Lupar basin; Sungei Engkari mainstream, ca. 500 m – 1 km upstream of Nanga Segerak Field Station, just past Sungei Tapayang; 01°24.875′N 112°00.379′E, 289 m asl; colls. Tan HH et al, 22 September 2018 GoogleMaps . --- ZRC 60393 View Materials , 1 ex., 160.1 mm SL; East Malaysia: Sarawak: Sri Aman Division : Lupar basin; Sungei Kaup , tributary of Sungei Engkari (downstream of Nanga Segerak Field Station, at main fork); 01°24.084′N 111°59.494′E, 246 m asl; colls. Tan HH et al, 26 September 2018 GoogleMaps . --- BMNH 1983.6.20 : 4, 1 ex., 150.8 mm SL; East Malaysia: Sarawak: Sri Aman Division : Lupar basin; Batang Ai; Cramphorn J et al, 1982 . --- BMNH 1983.6.20 : 13-14, 2 ex., 78.7–101.5 mm SL; East Malaysia: Sarawak: Sri Aman Division: Lupar basin; Batang Ai; Cramphorn J et al, 1982 . --- BMNH 1983.6.20 : 97- 98, 2 ex., 83.3–162.3 mm SL; East Malaysia: Sarawak: Sri Aman Division: Lupar basin; Batang Ai; Cramphorn J et al, 1982 . --- UNIMAS.P.00448-49, 2 ex., 102.0–172.0 mm SL; East Malaysia: Sarawak: Sungei Pedid, upstream area of Sarawak Kanan River; J. Grinang, October 2023 . --- UNIMAS.P.00093, 1 ex., 110.0 mm SL; East Malaysia: Sarawak: Sawah River, tributary of Sarawak Kiri River; February 2012 . --- UNIMAS.P.00153, 1 ex., 85.0 mm SL; East Malaysia: Sarawak: Sungei Duyuh, tributary of Sarawak Kanan River; September 2016 . --- UNIMAS.P.00450, 2 ex., 106–134 mm SL; East Malaysia: Sarawak: Simunjan District; streams in Sabal Forest Reserve; Badiozaman Sulaiman et al., 23–29 November 2024 .

Diagnosis. Hampala lupar is distinguished from its congeners by the following combination of characters: lateral line scales 26–27; three black bars on body, bar 0 2½–3 scales wide, bar 1 3–3½ scales wide, bar 2 3–4 scales wide, all bars apparent even at juvenile stage; upper and lower edges of caudal fin with a black marginal band; all fins orange when live.

Description. See Table 1 for biometric data and Figs. 1, 2 for general appearance.

Head pointed, wedge-shaped, head large (31.3–34.9 % SL). Mouth terminal, gape oblique and large with posterior edge beyond anterior margin of eye; with a pair of maxillary barbels, each barbel at corner of mouth, as long or longer than eye diameter. Relatively large eye (eye diameter 18.1–24.4 % HL), and long snout (snout length 31.7–34.7 % HL). Body relatively compressed, elongate and deepest at dorsal fin (body depth at dorsal-fin origin 19.7–28.7 % SL; body depth at anus 18.6–21.2 % SL), tapering to narrowest at caudal peduncle (caudal peduncle depth 11.8–13.7 % SL). All fins triangular in outline, except caudal fin which is deeply forked (upper caudal lobe 31.6–34.1 % SL, median caudal 12.0–14.2 % SL, lower caudal lobe 29.6–31.2 % SL). Dorsal fin moderately short with 11 ½ rays (dorsal-fin base length 14.2–16.8 % SL), positioned past mid-body (predorsal length 53.3–55.3 % SL). Anal fin short with 7 ½ rays (anal-fin base length 8.2–11.1 % SL), pre-anal length 72.8–78.3 % SL. Pectoral fin moderately long, with 15 rays (pectoral fin length 18.6–21.1 % SL). Pelvic fin shorter than pectoral fin, with 9 rays (pelvic-fin base length 16.8–19.8 % SL), prepelvic length 51.0–54.5 % SL. Pelvic auxillary scale present, about ⅓ pelvic-fin length.

Lateral line complete, perforating large scales in a continuous series (26–27, mode 27), starting just above opercular opening, gently sloping downwards towards pelvic fin, 3 scales above pelvic-fin origin and running parallel to venter towards middle of caudal peduncle, with additional 2–3 (mode 2) perforated scales on caudal-fin base. Predorsal scales 9–11 (mode 10); 8th lateral-line scale in relation to dorsal-fin origin; 14½–17th (mode 17th) lateral-line scale in relation to anal-fin origin; 7½–8th (mode 8th) lateral-line scale in relation to pelvic-fin origin. Circumpeduncular scales 13.

Fresh colouration. See Fig. 1. Body silvery-gold, posterior margin of each scale with thin band of melanophores, greyish-brown on dorsum, cream on venter. Opercle with orangish sheen when live. Consistently 3 black bars on the body, even in juveniles. Bar 0 originating just posterior to opercle opening, may appear as a large black blotch or bar, 2–3 scales wide (see Table 2 for descriptors for body bars). Bar 1 originating at dorsal-fin origin (at lateral line scale 9½–12½), bar width may cover entire dorsal-fin base and narrowing downwards from 3½ to 3 scales wide, bar at median of body 3 scales wide. Bar 2 originating at lateral line scale 18–23, wider at dorsum and narrowing downwards from 4 to 3 scales wide, bar at median of body 3 scales wide. In larger specimens, all 3 bars not reaching to venter. In juvenile stage (examined specimen, ZRC 60452, 42.9 mm SL), bars 0 and 2 are rounded black blotches, bar 1 is narrow and continuous to venter, 1–1½ scales wide. All fins orange-red. Both dorsal and pectoral fins with black leading edge. Upper and lower edges of caudal fin with black marginal stripe.

Black bars of H. lupar exhibit higher colour contrast in habitat than in captivity.

Preserved colouration. See Fig. 2. All bright colours faded or bleached. Older preserved specimens may appear yellowish or brownish. Body and fin patterns as above.

Field observations. The Engkari river flows through V-shaped valleys and consists of high-velocity waters flowing over a rocky bottom. There are occasional deeper water pools, with slower flowing water. The rocks exhibit dark shades of grey, brown, and black. In areas where the canopy cover is good, water visibility is very poor due to insufficient light penetration. Large individuals of H. lupar prefer these deeper water bodies. Juveniles are found near river banks in more shallow water, and amongst submerged roots and above leaf litter. Batang Ai is now a man-made reservoir, and the riverine habitats are permanently flooded, but feeder streams and header waters are still intact.

Syntopic fish species include (see Tan, 2021 for a more complete listing): Barbodes banksi , Barbonymus collingwoodii , Lobocheilos ovalis , Osteochilus sarawakensis , O. waandersii , Paracrossochilus vittatus , Tor tambra , Tor tambroides ( Cyprinidae ), Rasbora fasciata ( Danionidae ), Engkaria eubranchus , Gastromyzon megalepis , G. stellatus , Neogastromyzon pauciradiatus , Parhomaloptera microstoma ( Gastromyzontidae ), Pangio piperata ( Cobitidae ), Nemacheilus kapuasensis ( Nemacheilidae ), Leiocassis micropogon ( Bagridae ), Clarias planiceps ( Clariidae ), Glyptothorax major ( Sisoridae ), Macrognathus circumcinctus , Mastacembelus unicolor ( Mastacembelidae ), and Channa lucius ( Channidae ).

Distribution. Hampala lupar appears to have only been observed in southern Sarawak, from the Lupar to the Sarawak River basins (see Fig. 10). The presence of the population at the upper Sarawak River was reported by Michael Lo (pers. comm.) as well as observations by the second author.

Etymology. Named after the Lupar River basin, where it was first recorded in the 1980s. Used as a noun in genitive. Cramphorn (1982: 29) who had misidentified H. lupar as “ H. bimaculata (3 spots)”, listed the following local names for this species: Adong Tekalang Maioh (Iban) and Adong Takalang Banyak (Malay).

Comparative notes. For illustrative purposes, topotypic material of H. bimaculata from both the Kayan and Mahakam River basins are shown in Fig. 7 and from the Kapuas basin in Fig. 8 for comparison; other Hampala species are in Fig. 9. Hampala bimaculata appears to have a more robust build and wider black body bars. If morphometric data are compared only between H. lupar and H. bimaculata from North and East Kalimantan, there are the following differences: Hampala lupar has a narrower head than H. bimaculata (head width 42.1–46.0, mean 44.3 % HL, vs. 42.9–49.0, mean 45.5); smaller eye than H. bimaculata (diameter 18.1–24.4, mean 20.9 % HL, vs. 18.1–25.9, mean 21.7). The distribution of the two new species and Hampala within Borneo is illustrated in Fig. 10.

Hampala lupar has a black blotch or bar just posterior to the gill opening, and presence of this bar 0 is the most obvious difference to H. bimaculata and H. katibas . See Table 2 for the body bar descriptor. Overall, the black body bars of H. bimaculata are slightly wider than H. lupar . For the juvenile body pattern, this difference in width is even more obvious (see Fig. 3). Bar 0 in H. lupar is a rounded black blotch, which is absent in H. bimaculata and H. katibas . Bar 1 in H. lupar is slender, covering around ⅓ of the dorsal-fin base and continuous from dorsum to venter, but is wide in H. bimaculata , covering nearly the whole dorsal-fin base, and does not extend to venter; bar 1 is narrow in H. katibas , covering around half of the dorsal-fin base and does not extend to venter. Bar 2 in H. lupar is a rounded black blotch, but a wide black bar in H. bimaculata and H. katibas .

Based on body pattern alone (see Figs. 2, 3), H. lupar can be easily distinguished from the rest of its congeners. With its three bar body pattern, Hampala lupar can be differentiated from H. lopezi , which has a central black stripe; from H. ampalong and H. salweenensis , which both have two black spots; from H. dispar , which has a single spot; from H. macrolepidota which has a single thin black bar from the dorsal-fin origin and an occasional caudal peduncle black spot; and from H. sabana , which has a single very wide black triangular bar below the dorsal-fin base.