Population densities of Onymacris bicolor (Haag) (Coleoptera; Tenebrionidae), a locally abundant, endemic species of the Namib Desert, were estimated in four habitat types of the dunefields of the Skeleton Coast Park using the Lincoln Petersen Index and the Jolly Seber method. Keywords: Population, Habitat, Nara plants, Succulent plant, PsammophiIous tenebrionid beetle species, Dune slipface, Vegetation, Sesuvium sesuviodes plant.