@article {1567,
	title = {Diversity in the weapons of sexual selection: horn evolution in the beetle genus Onthophagus (Coleoptera: Scarabaeidae)},
	journal = {Evolution},
	volume = {59},
	number = {5},
	year = {2005},
	month = {Jan},
	pages = {1060-1084},
	abstract = {Both ornaments and weapons of sexual selection frequently exhibit prolific interspecific diversity of form. Yet, most studies of this diversity have focused on ornaments involved with female mate choice, rather than on the weapons of male competition. With few exceptions, the mechanisms of divergence in weapon morphology remain largely unexplored. Here, we characterize the evolutionary radiation of one type of weapon: beetle horns. We use partial sequences from four nuclear and three mitochondrial genes to develop a phylogenetic hypothesis for a worldwide sample of 48 species from the dung beetle genus Onthophagus (Coleoptera: Scarabaeidae). We then use these data to test for multiple evolutionary origins of horns and to characterize the evolutionary radiation of horns. Although our limited sampling of one of the world{\textquoteright}s most species-rich genera almost certainly underestimates the number of evolutionary events, our phylogeny reveals prolific evolutionary lability of these exaggerated sexually selected weapons (more than 25 separate gains and losses of five different horn types). We discuss these results in the context of the natural history of these beetles and explore ways that sexual selection and ecology may have interacted to generate this extraordinary diversity of weapon morphology. },
	keywords = {Adaptive radiation, beetle horns, character divergence, male competition, Onthophagus, phylogeny, sexual selection, weapons.},
	author = {Emlen, Douglas J. and Marangelo, Jennifer and Ball, Bernard and Cunningham, Clifford}
}
@article {1748,
	title = {Phylogeny of Scarabaeus (Pachysoma MacLeay) stat. nov., and related flightless Scarabaeini (Scarabaeidae: Scarabaeinae)},
	journal = {Annals of the Transvaal Museum},
	volume = {40},
	year = {2003},
	pages = {47-71},
	abstract = {ThemonophylyofPachysomaMacLeayisassessedviacladisticanalysis,basedonsixty-fouradultcharactersfrom thirty-seventaxacomprisingall currentlyandpreviously recognizedgenerainScarabaeini, except Madateuchus Paulian.PachysomacomprisesamonophyleticcladeofderivedspeciesofScarabaeusandNeopachysomaFerreira isthesisterlineageofPachysomasensustricto.Scarabaeus(Pachysoma)stat. nov. isconsideredasubgenusof ScarabaeusLinnaeuswhileNeopachysomaFerreiraismaintainedasasynonymof Pachysomasensulato. NeomnematiumJanssenstogether withMnematiumMacLeayispolyphyletic, whilethelatter isparaphyletic. MnematiumMacLeayandNeomnematiumJanssensaremaintainedassynonymsofScarabaeus,andtheirspecies includedinsubgeneraScarabaeus(Scarabaeus) andScarabaeus(Scarabaeolus).DrepanopodusJanssens, KheperJanssensandSceliagesWestwood,asderivedcladesofScarabaeus,couldalsoberecognizedassubgen- eratomaintainamonophyleticScarabaeus,but aremaintainedasgenerapendingfurther work. Aridificationof theNamibDesertispostulatedtohaveinitiatedtheevolutionofScarabaeus(Pachysoma),whichfeedondrydungor detritusandarederivedfromaball-rollingandwet-dung-feedingScarabaeus-likeancestor. Theevolutionof flightlessnessandfoodrelocationstrategy,biogeography,andadditionaldistributionalandbiologicalinformationare presented for the group. },
	keywords = {Aptery, Biology, Drepanopodus, Kheper, Pachylomerus, Pachysoma, phylogeny, Psammophily, Scarabaeolus, Scarabaeus, Sceliages},
	author = {Harrison, James du G. and Philips, T. Keith}
}
@article {1978,
	title = {Biogeografia de areas y biogeografia de artropodos holarticos y mediterraneos},
	journal = {Boletin de la Sociedad Entomologica Aragonesa},
	volume = {26},
	year = {1999},
	pages = {535-560},
	keywords = {arthropods, dispersal, historical biogeography, holartic region, phylogeny, vicariance},
	author = {Martin-Piera, Fermin and Sanmartin, Isabel}
}
@article {2213,
	title = {Phylogeography of the Namib Desert dung beetles Scarabaeus (Pachysoma) MacLeay (Coleoptera: Scarabaeidae)},
	journal = {Journal of Biogeography},
	volume = {32},
	year = {2005},
	pages = {75-84},
	abstract = {Aim Namib biogeography in many instances remains reliant on advanced and detailed systematic studies. This study attempts to combine molecular phylogenetic data, geology and palaeo-climatic data to (i) resolve the relationships of the 13 morphological species of Scarabaeus (Pachysoma) and (ii) relate their evolution to past climatic and geological events. Location South Africa and Namibia. Methods Sequencing of a 1197 bp segment of the mitochondrial cytochrome oxidase I (COI) gene of the 13 species within Scarabaeus (Pachysoma) was undertaken. Analyses performed included Parsimony and Maximum Likelihood as well as imposing a molecular clock. Results The molecular phylogeny showed strong support for 11 of the 13 morphological species. The remaining two species, S. (P.) glentoni and S. (P.) hippocrates, formed a complex and could not be assigned specific status on the basis of the COI gene phylogeny. Strong support for the three species formerly classified within the genus Neopachysoma was consistently obtained. The subgenus appears to have arisen c. 2.9 Ma. Species within the subgenus arose at different times, with the common ancestor to Neopachysoma and the hippocrates complex having evolved 2.65 and 2.4 Ma, respectively. Scarabaeus (P.) denticollis, S. (P.) rotundigenus, S. (P.) rodriguesi and S. (P.) schinzi are some of the youngest species, having diverged between 2 million and 600,000 years ago. Main conclusions Scarabaeus (Pachysoma) is a derived monophyletic clade within the Scarabaeini. The subgenus appears to be young in comparison with the age of the Namib Desert, which dates back to the Miocene (c. 15 Ma). The psammophilous taxa are shown to disperse with their substratum and habitat, barchan dunes. Clear south/north evolutionary gradients can be seen within the species of this subgenus, which are consistent with the unidirectional wind regime. Species with a suite of mostly plesiomorphic characters have a southerly distribution while their derived psammophilous relatives have central to northern Namib distributions. Major rivers such as the Orange, Buffels and Holgat appear to be gene barriers to certain species as well as areas of origin of speciation events. },
	keywords = {Aptery, biogeography, COLEOPTERA, cytochrome oxidase I, endemic, mitochondrial DNA, namib desert, phylogeny, Scarabaeidae, Scarabaeus (Pachysoma).},
	author = {Sole, Catherine L. and Scholtz, Clarke H. and Bastos, Armanda D. S.}
}
