Redescription and natural history of Meligethes longulus Schilsky, 1894, and provisional revision of the M-coracinus species-complex (Coleoptera, Nitidulidae, Meligethinae)

The taxonomic identification and a re-description of the problematic Meligethes longulus Schilsky, 1894 from eastern Turkey are presented. This species, belonging to the M. coracinus complex and known so far on the basis of a single immature holotype,,v-as repeatedly confused in the past with other closely related taxa, thus introducing considerable instability in the nomenclature and taxonomy of the whole group, involving several distinct biological species throughout southern Europe and western Asia. The recent re-discovery of this species in eastern Turkey allowed ill. longulus to be definitely identified as being an extremely rare and localized species, with larval stages strictly associated with the host-plant Matthiola odoratissima (Bieb.) R.Br. (Brassicaceae), in dry exposed terrigenous and sandy hill slopes of eastern Turkey. An updated key to the identification of both described and un-described members of the M. coracinus complex is also presented. and a rather isolated species of the M. coracinus complex from southern Turkey, M. cristofaroi n. sp., is described as new. A preliminary evolutionary scenario of the whole species-complex, based also on results from a companion molecular research, is finally discussed.