Biogeography of Aphodiinae dung beetles based on the regional composition and distribution patterns of genera

Aim To examine current biogeographical patterns of Aphodiinae dung beetles (Coleoptera: Scarabaeoidea: Scarabaeidae) in order to reveal relationships among regions and their potential impact on the diversification of this group. Location Worldwide. Methods Information about all Aphodiinae genera was obtained from the literature. An occurrence matrix was built for the six worldwide biogeographical regions, and their faunas were characterized through simple statistics. Regional variations and similarities were further explored using co-occurrence and nestedness analyses, sequential agglomerative, hierarchical and nested clustering (SAHN), and a parsimony analysis of endemicity (PAE). Mantel tests were also employed to assess the relationships between several characteristics of the regions and their faunas. Results The Palaearctic and Palaeotropical regions showed the highest total numbers of Aphodiinae genera and the greatest generic endemism. Both these regions and the Oriental also showed higher numbers of genera than would be expected according to their size. Co-occurrence and nestedness analyses confirmed the non-randomness of the distribution of genera. Clustering and PAE showed that the Palaearctic and Oriental regions are the most similar, followed by the Palaeotropical region. Regional dissimilarity in genera composition was related to biological and historical traits, but not to ecoregions. Main conclusions A structured geographical pattern for Aphodiinae was confirmed. Land continuity and proximity in the long term could have played a unifying role in regional faunas. We suggest that the different biogeographical regions have acted as either macroevolutionary sources (basically the Palaearctic and the Palaeotropical regions) or sink regions, according to their role as diversification centres. We review the processes and events that could account for current patterns of Aphodiinae diversity.