Phylogeny of the familyTrogidae (Coleoptera:Scarabaeoidea) inferred from mitochondrial and nuclear ribosomalDNAsequence data

Abstract

AbstractTrogidae constitute a monophyletic and biologically unique family withinScarabaeoidea, being the only keratinophagous group in the superfamily. Traditionally, the family has been divided into three distinctive genera,PolynoncusBurmeister,OmorgusErichson andTroxFabricius. Although the taxonomy of the group is relatively well studied, changes to the existing classification have recently been proposed and the family as currently constituted has not been subjected to phylogenetic analyses. Here we present a molecular phylogeny for this cosmopolitan family based on three partially sequenced gene regions:16SrRNA,18SrRNAand28SrRNA(domain 2). Included in the analyses are representatives belonging to four of the five extant genera (and three of the four subgenera) from all major zoogeographic regions, representing about 20% of the known trogid species diversity in the family. Phylogenetic analyses performed includedparsimony andBayesianinference. We deduce their historical biogeography by using trogid fossils as calibration points for divergence estimates. Our analyses resolved relationships between and within genera and subgenera that are largely congruent with existing phylogeny hypotheses based on morphological data. We recovered four well‐supported radiations:Polynoncus,Omorgus,HolarcticTroxandAfricanPhoberusMacLeay. On the basis of this study, it is proposed that taxonomic changes to the generic classification of the family be made. The subgeneraTroxandPhoberusshould be elevated to genera to include theHolarctic and all theAfrotropical species, respectively, andAfromorgusreturned to subgeneric rank. Estimates of divergence time are consistent with aPangaean origin of the family in theEarlyJurassic. The subsequent diversification of the major lineages is largely attributed to the break‐up ofPangaea andGondwana in theMiddleJurassic and earlyLateCretaceous, respectively.