An Overview of the Classification and Evolution of the Major Scarab Beetle Clades (coleoptera: Scarabaeoidea) Based on Preliminary Molecular Analyses

We present a preliminary overview of our molecular phylogenetics research on the superfamily Scarabaeoidea. The molecular data consists of 28S ribosomal DNA sequences (mainly D2 and D3 expansion regions) for over 600 taxa and 18S ribosomal DNA sequences (mainly E17 to E35 expansion regions) for over 150 representative taxa within the lineages sampled. Based on our preliminary molecular phylogenetic results, Scarabaeoidea includes three major groups: 1) Geotrupidae, Passalidae, and Pleocomidae; 2) Lucanidae, Diphyllostomatidae, Trogidae, and Glaresidae; and 3) Hybosoridae, Ochodaeidae, Glaphyridae, and Scarabaeidae. The broad evolutionary patterns within the Scarabaeoidea are discussed with respect to phylogeny and evolution. Twenty-four years ago, Henry Howden published the very first phylogenetic analysis of the Scarabaeoidea based on the principles of cladistics (Howden 1982). Since then, there have been numerous other attempts to reconstruct the evolutionary history of the Scarabaeoidea (most notable are the efforts of Browne and Scholtz 1995, 1996, 1998, 1999), as well as many astronomical leaps in our ability to compile and analyze morphological and molecular data for the purposes of phylogenetics. In this paper, we introduce our attempts to reconstruct the phylogeny of the Scarabaeoidea using molecular data, and we compare our preliminary results to previous studies. We recognize that our current state of scarab systematics is a community effort that has been built through time, and that achievements are made by standing on the shoulders of the pioneers who made the first forays into new areas of systematics research. With this in mind, and to honor his long and innovative career, we dedicate this paper to Henry Howden. For the past five years, we have been conducting research on the molecular phylogenetics of the superfamily Scarabaeoidea. During that time, we have accumulated 28S ribosomal DNA sequences for over 600 taxa and 18S ribosomal DNA sequences for over 150 representative taxa within the lineages sampled. We have attempted to sample all major Scarabaeoidea lineages worldwide in order to get as complete a picture as possible of the phylogeny, evolution, and biogeographical patterns of scarab beetles. Numerous outgroup taxa also have Coleopterists Society Monograph Number 5:35–46. 2006.