A reappraisal of the 'fracticornis-opacicollis' taxonomic complex of the genus Onthophagus Latreille using allozymes (Coleoptera, Scarabaeoidea)

The present taxonomic status of the so called fracticornis-opacicollis comp lex of the genus Onthaphagus, Onthophagus fracticornis (Preyssler, 1790), O nthaphagus simillis(Scriba, 1790) and Onthophagus opacicollis Reitter, 1892 is still controversial. Discrepancies mainly involve the status of O. simi lis and O. opacicollis. A genetic analysis of nine populations of this comp lex using eight loci is presented, indicating that: (i) O. fracticornis is a good species, and (ii) the genetic distances between O. opacicollis and 0 . similis populations as a function of the biogeographic scenery (allopatry versus sympatry), indicate that they are not completely reproductively iso lated across their entire geographic range, thus suggesting a still unfinis hed speciation in different areas. The data demonstrate both the existence of some gene flow between O. opacicollis and O. simulis in one place ('El B arraco'; Central Spain) and isolation in others ('S-a Nevada'; South-east S pain). Geographic areas hosting populations of both taxa with intermediate genetic distances ('Donana'; South-west Spain) also exist in the Iberian Pe ninsula.