Biogeography of Cymatodera (Cleridae: Tillinae), for richer in North America and for poorer in South America

Cymatodera (Tillinae) is composed of predatory beetles restricted to the New World. This genus is one of the most speciose genera within Cleridae, with approximately 138 described species. The southwestern United States, together with western and central Mexico, represent the areas of highest species richness. The number of species gradually declines southward, and there are very few species known from South America. We propose a hypothesis to explain this gradual decline of species richness based on geological events and the ecological preferences of this group of checkered beetles.