Key words. Alticinae, Boraginaceae, Afrotropical Region, Longitarsus, Mediterranean area, disjunct distribution. SUMMARY In this paper the disjunct distribution of two Longitarsus species-groups associated with Boraginaceae: capensis-group, restricted to the southern Africa and presently including 15 species, and anchusae-group (sensu Biondi, 1995), widespread in the western Palaearctic area with 4 species, is discussed. Some hypotheses explaining the separate distributions of Mediterranean and South African groups are proposed. Finally, the host-plant shift from native Lobostemon spp. to the introduced plant Echium plantagineum L. shown by some species of the capensis group is also discussed. INTRODUCTION Longitarsus Latreille, as described in Berthold (1827), is presently the largest genus within Chrysomelidae, Alticinae with about 600 known species occur- ring throughout all zoogeographical regions (Biondi & D’Alessandro, 2008). This flea beetle genus is well represented in the Mediterranean area (about 160 species), where is better known from an autecological standpoint (Biondi, 1996). Longitarsus species occurring in the Mediterranean area are known to feed, as adults, on plants of different botanical families, the preferred being Boraginaceae (26.4%), Lamiaceae (24.9%), Asteraceae (13.8%), Plantaginaceae (9.5%), and Scrophulariaceae (9.5%) (Fig. 1). Particularly, species-groups, such as aeneus, anchusae, exsoletus and echii feeding on Boraginaceae, show an eleva- ted degree of trophic specialization (Jolivet & Hawkeswood, 1995; Biondi, 1996) and include mainly oligotopic species, generally termophilous (Figs 2-3). In the Biogeographia vol. XXIX - 2008 (Pubblicato il 30 dicembre 2008) The Mediterranean-southern African disjunct distribution pattern Mediterranean-southern African disjunct distribution and flea beetles: the example of the “black species” of Longitarsus associated with Boraginaceae (Coleoptera, Chrysomelidae, Alticinae) MAURIZIO BIONDI, PAOLA D’ALESSANDRO Dipartimento di Scienze Ambientali, Università de L’Aquila, 67010 Coppito, L’Aquila, Italy e-mail: biondi@univaq.it, paola.dalessandro@univaq.it.