1 Dipartimento di Biologia Animale e dellÕUomo, Sapienza Universita ` di Roma, Rome, Italy; 2 Ecole dÕInge´nieurs de Purpan, France; 3 Dipartimento di Biologia, Universita ` ÔRoma TreÕ, Rome, Italy Data on molecular taxonomy and genetic diversification of the European Hermit beetles, a species complex of endangered insects (Coleoptera: Scarabaeidae, Cetoniinae, Osmoderma) P. Audisio 1 , H. Brustel 2 , G. M. Carpaneto 3 , G. Coletti 1 , E. Mancini 1 , M. Trizzino 1 , G. Antonini 1 and A. De Biase 1 Abstract A molecular analysis was carried out on the European hermit beetles (the Osmoderma eremita species complex) to explore their genetic diversification and the robustness of previous morphologically based taxonomic arrangements. Complete sequences of mtDNA cytochrome C oxidase I gene were obtained from 26 individuals. Mean levels of interspecific sequence divergence ranged from 0.044 to 0.186. The results indicate a clear-cut distinction between two clades. The first one includes the W-European O. eremita Scopoli 1763; and the two Italian endemic taxa Osmoderma italicum Sparacio, 2000 and Osmoderma cristinae Sparacio, 1994; from southern peninsular Italy and Sicily, respectively. The second one includes the widespread E-European Osmoderma barnabita; and the southern Balcanic Osmoderma lassallei Baraud and Tauzin, 1991 from Greece and European Turkey. Within the two clades, molecular and morphological data well support a specific rank for O. lassallei and O. barnabita on one side, and for O. eremita and O. cristinae on the other side, while the taxonomic position of O. italicum, more closely related to O. eremita, is still uncertain. Current geographical distribution, interspecific genetic diversification, and very low levels of intraspecific genetic divergence in western European populations of O. eremita sensu stricto are hypothesized to be the result of multiple speciation events (mainly occurred in refugial forest areas of the Italian and Balkan peninsulas and Sicily before and during the Pleistocene glacial peaks), followed by fast post-glacial northward and westward expansion of some species. Key words: cytochrome C oxidase I gene – molecular taxonomy – sibling species – threatened species – Osmoderma – Coleoptera Introduction Hermit beetles are a group of flower chafers (Scarabaeidae: subfamily Cetoniinae: tribe Trichiini) of the genus Osmoder- ma LePeletier de Saint-Fargeau and Serville, 1828. They are large scarab beetles (more than 30 mm long) that live in old hollow trees. We adopt here the current generic name Osmoderma instead of the recently re-introduced name Gymnodus Kirby, 1827 (A ´ da´m 1994, 2003; Gusakov 2002), according to a submitted proposal to the International Commission on Zoological Nomenclature (ICZN) and its recent opinion (Krell et al. 2006; Audisio et al. 2007; Barclay 2007; ICZN 2007). This genus includes a dozen of species widely spread throughout the Palaearctic and the Nearctic regions (see the world checklist in Audisio et al. 2007). The geographic distribution and the ecological traits of the European species, joined together under the name Osmoderma eremita sensu lato, have been recently summarized by Ranius and Nilsson (1997), Schaffrath (2003a,b), Ranius (2000, 2001), Ranius and Hedin (2001, 2004) and Ranius et al. (2005). These studies, supported by many other surveys conducted at local level, evidenced a strong decline suffered by this taxonomic group throughout its distribution range, and reported extinction from some coun- tries owing to habitat loss and intensive forest management. For this reason, O. eremita has been listed as a priority species in Annex IV of the EUÕs Habitat Directive (Luce 1996, 2001; Galante and Verdu´ 2000; Audisio et al. 2003; Ranius et al. 2005). As discussed in a series of recent contributions (Sparacio 1994, 2000; Tauzin 1994a,b, 1996, 2000, 2002; Krell 1997; Gusakov 2002; Audisio et al. 2003; Dutto 2003; Ranius and Hedin 2004, 2005), under the name O. eremita are probably included at least two or more distinct species or semi-species, whose taxonomic rank has been a matter of strongly contro- versial interpretations. In fact, some studies (Nu¨ssler 1986; Sparacio 1994, 2000; Tauzin 1994b, 2006; Gusakov 2002; Audisio et al. 2003; Ranius and Hedin 2004; Brustel 2004) suggested a morphological distinction of at least two up to five substantially allopatric semi-species, whose actual taxonomic position is difficult to ascertain: • Osmoderma eremita Scopoli, 1763, widespread in western Europe, eastwards to Germany and western Slovenia. • Osmoderma cristinae Sparacio, 1994, confined to Sicily. • Osmoderma italicum Sparacio, 2000, occurring in southern Italy. • Osmoderma lassallei Baraud and Tauzin, 1991, distributed in Greece and European Turkey. • Osmoderma coriarium De Geer, 1774; sensu Gusakov, 2002; from eastern Europe (this taxon hereafter is treated under the combination Osmoderma barnabita see later and in the Commented World Checklist of Audisio et al. 2007). However, until very recently, O. eremita s.l. was provisionally treated as one species with clear geographic morphological variation and three recognized distinct sub- species (O. eremita eremita, O. eremita lassallei and O. eremita cristinae (Krell 1997, 2004; Shokhin and Bozadjiev 2003). The aim of this paper is mainly to test the genetic diversification among the European species or semi-species of the O. eremita complex; to achieve data towards a reasonable and objectively supported taxonomic arrange- ment for the whole complex; and to provide a preliminary scenario of their phylogenetic relationships based on molecular data. Audisio et al. (2007) can be referred for the rationale of the specific epithets used in the present study. Ó 2008 The Authors Journal compilation Ó 2008 Blackwell Verlag, Berlin Accepted on 18 February 2008 J Zool Syst Evol Res doi: 10.1111/j.1439-0469.2008.00475.x J Zool Syst Evol Res (2009) 47(1), 88–95