Aquatic Coleoptera Of Singapore: Species Richness, Ecology And Conservation # Author Hendrich, Lars Author Balke, Michael text Raffles Bulletin of Zoology 2004 52 1 97 145 journal article 10.5281/zenodo.13244881 2345-7600 13244881 Hydaticus reductus Régimbart, 1899 Hydaticus reductus Régimbart, 1899: 357 ; Zimmermann, 1920: 224 ; Vazirani, 1977: 80 ; Nilsson, 2001: 105 . Hydaticus sexguttatus Régimbart, 1899 : Balke et al., 1999: 325 (part). Material examined. – 1 specimen – Central catchment area - 1 male , MacRitchie Reservoir , 21 Apr.1994 , NS 124 F/H, coll. K. L. Yeo ( ZRC ) . Distribution. – Indonesia [ Kalimantan , Pontianak] ( Régimbart, 1899 ; Vazirani, 1977 ), West Malaysia and Singapore (Balke et al., 1999). Ecology. – Hydaticus reductus inhabits shaded and shallow freshwater pools in lowland forests. In general the habitat is rich in rotten leaves and wood. The population density of the species seems to be very low (pers. observ. in West Malaysia ). Thus it is difficult to sample and quite rare in collections. Remarks. – Hydaticus reductus and other species ( Hydaticus concolor Sharp, 1882 ; H. sexguttatus Régimbart, 1899 ) form an assemblage of small to medium sized, comparably dark species that remain to be revised. TRIBE CYBISTRINI