Canthydrus morsbachi (Wehncke, 1876) Hydrocanthus morsbachi Wehncke, 1876: 222. Canthydrus morsbachi (Wehncke) - Sharp, 1882: 276; Régimbart, 1899: 247; Zimmermann, 1920: 12, 1928: 2; Vazirani, 1968: 232; 1977: 7; Yano et al., 1983a: 16. Material examined. – 165 specimens – Central catchment area - 1 ex., SICC, Sime Rd., MacRitchie Forest, plot 22, 7 May.1993, NS 72, coll. T.W. Koh et al. (ZRC). Sungai Buloh - 3 ex., 15 Nov.1990, coll. C. M. Yang & K. L. Yeo (ZRC); 6 ex., shallow pool no. 3, 4 Dec.1990, coll. C. M. Yang & K. L. Yeo (ZRC); 4 ex., pond, 34e, 16 Jan.1991, coll. C. M. Yang et al. (ZRC); 6 ex., 10 Apr.1991, 34b, coll. C. M. Yang (ZRC); 43 ex., fish pond, H.R. light trap, 10 Jul.1992, y 804, coll. K. Lim (ZRC); 78 ex., fish pond, 5 Dec.1996, coll. L. Hendrich (CBH, ZRC). Other areas - 1 ex., Pasir Ris Mangrove, at light, 14 Nov.1989, coll. Y.H. Koo & K. Lim (ZRC); 16 ex., Fish pond near Kranji, Turut Track off New Tiew Road, 10 Oct.1990, coll. C. M. Yang et al. (ZRC); 2 ex., Neo Tiew Road, Turat track, 27 Nov.1990, ZRC.6., coll. K. L. Yeo (ZRC); 2 ex., Lorong Banir, pond 1, 16 Jun.1995, NS 190, coll. C. M. Yang & H. K. Lua (ZRC); 3 ex., pond 1, 28 Apr.1997, coll. M. Balke & L. Hendrich (CBH). Distribution. – Cambodia, India, Indonesia [Sumatra], Myanmar, Singapore, Vietnam. An African [Congo] report needs to be confirmed (Vazirani, 1977). Ecology. – An inhabitant of shallow, muddy water of open or semi-shaded, more permanent swamps and artificial ponds (e.g., fish ponds and paddy fields)(see Yano et al., 1983a). The habitat must be rich in rotten leaves and submerged plants. The species also occurs in brackish waters of coastal and mangrove swamps (e.g., Sungai Buloh Nature Park and Pasir Ris Mangrove).

Published as part of Hendrich, Lars & Balke, Michael, 2004, Aquatic Coleoptera Of Singapore: Species Richness, Ecology And Conservation #, pp. 97-145 in Raffles Bulletin of Zoology 52 (1) on page 108, DOI: 10.5281/zenodo.13244881