Lissochilus hendersoni Herre 1940: 10 (Penang); Tweedie 1940: 73 (Penang); Menon & Yazdani 1963: 113 (Penang); Alfred 1971: 71 (Penang)

Acrossocheilus hendersoni: Alfred 1963a: 146 (Sg. Batu Feringgi, Sg. Teluk Bahang, Sg. Balik Pulau and Sg. Pinang of Penang); Johnson 1967: 724 (Penang)

Neolissochilus hendersoni: Rainboth 1985: 31 (Penang); Ahmad & Lim 2006: 109 (waterfall stream at Durian Perangin, Sg. Korok, Sg. Temah Kecil of Langkawi)

Material examined. UMKL 6084, 4 ex., 66.5–88.2 mm SL; Peninsular Malaysia: Penang: Ayer Itam: Sg. Air Putih of Pinang drainage; coll. M.Z. Khaironizam, 6 Apr.2006. UMKL 5429, 23 ex., 54.8–120.5 mm SL; Peninsular Malaysia: Kedah: Sg. Batu Pahat of Merbok drainage; coll. A. Shahruddin, 15 Mar.2005. UMKL 6089, 15 ex., 44.6–111.8 mm SL; Peninsular Malaysia: Kedah: Sg. Batu Pahat of Merbok drainage; coll. M.Z. Khaironizam, 9 Jul.2006. UMKL 6090, 1 ex., 102.0 mm SL; Peninsular Malaysia: Kedah: Sg. Tupah of Merbok drainage; coll. M.Z. Khaironizam, 9 Jul.2006. UMKL 6091, 1 ex., 95.1 mm SL; Peninsular Malaysia: Kedah: Sg. Karangan of Muda drainage; coll. M.Z. Khaironizam, 14 Jul.2006. UMKL 6092, 5 ex., 55.6–122.7 mm SL; Peninsular Malaysia: Kedah: Sg. Sedim of Muda drainage; coll. M.Z. Khaironizam, 21 Jul.2006. UMKL 6081, 10 ex., 57.0– 74.3 mm SL; Peninsular Malaysia: Kelantan: Sg. Telaga Bijih of Golok drainage; coll. M.Z. Khaironizam, 18 Mar.2006. UMKL 6082, 12 ex., 56.6–76.5 mm SL; Peninsular Malaysia: Kelantan: Sg. Lata Perahu of Golok drainage; coll. M.Z. Khaironizam, 19 Mar.2006. UMKL 6083, 3 ex., 62.4–67.2 mm SL; Peninsular Malaysia: Kelantan: Sg. Sator of Golok drainage; coll. M.Z. Khaironizam, 19 Mar.2006.

Diagnosis. In Peninsular Malaysia, N. hendersoni is distinguished from N. soroides by the following unique combination of characters: lateral-line scales 18–22, usually 20 (vs. 20–24, usually 22); transverse scales 3.5/1/2 (vs. 3.5/1/3); predorsal scales 6–8 (vs. 8–10), scales from end of dorsal-fin base to origin of caudal-fin base 10–13, usually 12 (vs. 12–15, usually 14); scales from isthmus to pelvic-fin base 10–12, usually 11 (vs. 12–14, usually 13); scales at anal-fin base 3–5, usually 4 (vs. 4–6, usually 5); total gill rakers 12–14, usually 14 (vs. 14–17, usually, 16); gill rakers on lower arm 9–10, usually 9 (vs. 10–12, usually 11).

Description. General body shape and appearance are shown in Figure 5A. Mouth with smoothly rounded or 'normal' type of lower jaw (Fig. 5 B), sub-terminal or inferior. Lower lip present medially, varies, as thick as but never thicker than upper lip, always interrupted by post-labial groove; lips never developed into fleshy lobes. Anal fin when depressed usually reaching origin of caudal-fin base.

Distribution and habitat. Four specimens of N. hendersoni were found in runs with rapid flow and crystal clear water in Sg. Air Putih, a stream near Penang Hill Railway Station in Penang. This species was also found in the fast flowing and crystal clear streams of Sg. Batu Pahat and Sg. Tupah, Sg. Karangan and Sg. Sedim, tributaries of the Merbok and Muda drainages in Kedah. Its occurrence in Sg. Telaga Bijih, Sg. Lata Perahu and Sg. Sator of the Golok drainage in Tanah Merah, Kelantan were previously unrecorded (Fig. 1).

Remarks. Scale counts in N. hendersoni are lower than those of N. soroides, but other characteristics, including body coloration, are similar to those of N. soroides as discussed below.