Taxonomic composition and abundance of epigean tenebrionids (Coleoptera: Tenebrionidae) in the Chilean Coastal Matorral. Pitfall traps were used to examine the taxonomic composition and abundance of the Tenebrionidae (Coleoptera) assemblage in the desert portion of the Chilean Coastal Matorral. During the study period, the assemblage was dominated by four genera: Gyriosomus, Nycterinus, Praocis and Scotobius. The most diverse genus was Gyriosomus, with 6 species, followed by Praocis, with 4 species. In terms of abundance, Gyriosomus hoppei (Gray) accounted for 41% of total captures, followed by Gyriosomus foveopunctatus Fairmaire (10%), Nycterinus rugiceps Curtis (10%), and Praocis (Praocis) spinolai Solier (7%). Some species (e.g., Gyriosomus foveopunctatus, G. reedi Kulzer, G. modestus Kulzer, and Praocis (Praocis) elliptica) Philippi & Philippi showed restricted distribution in the study area and may be indicators of endemism. The dominance of Gyriosomus raises a series of questions regarding their levels of endemism, species diversity and distribution, and functional role in the ecosystem under study.