Strandzha (or Yildiz, in Turkish) is a low altitude mountain located at the southeast corner of the Balkan Peninsula. In fact, it is the last extensive European massif close to the Bosphorus, the point dividing Europe and Asia. Strandzha extends to both sides of the frontier between Bulgaria and Turkey, and the largest part of the mountain is in the latter country. It is bordered on the east by the Black Sea coast, and on the west by the Derventski Vazvisheniya Hills. The mountain has a number of physical characteristics that contribute to its high level of species diversity, such as relatively low altitude combined with varied mountainous relief, a wide variety of habitats, relatively well preserved natural ecosystems, and a mild climate for the proximity of the Black Sea and the Mediterranean. The vegetation has a markedly relict character with specific Euxinian floral elements (Georgiev 1993).

The fact that Strandzha’s invertebrate fauna is poorly investigated is largely due to the borderline location of the mountain. A vast area of the mountain was mostly inaccessible until recently. However, this helped to conserve some of the most interesting and species-rich ecosystems throughout Bulgaria and Turkey.

Knowledge of the ground-beetle fauna of Strandzha is considered insufficient and largely based on data from the Bulgarian part of the region and the available faunal records from casual collecting. The first records were published in the work of Czech entomologist Rambousek (1912). His paper includes 10 species from the region with the locality indicated as “Strandzha Mt.” [in Bulgarian], collected during the spring of the year 1909. In the twenties and thirties of the 20th century, data on eight representatives of the tribes Cicindelini and Carabini were added by Breuning (1928), Breuning (1932), Buresch and Kantardjieva (1928), Kantardjieva (1928) and Kantardjieva (1934). Later Mařan (1933), Mařan (1944), Mařan (1949) and Drensky et al. (1951) published supplementary information for six species. Fragmentary data for carabids from Strandzha appeared also in the works of Hieke (1970) – 1 species, Pawlowski (1973) – 5 species, Mlynář (1977) – 2 species, Müller-Motzfeld (1986) – 2 species, Wrase (1987) – 1 species, Casale (1988) – 1 species, Hůrka (1988) – 3 species, Vassilev and Necheva (1989) – 1 species and Wrase (1989) – 1 species. The most important contribution with respect to the carabids of the Bulgarian part of Strandzha and the adjacent Black Sea Coast, was the catalogue of Hieke and Wrase (1988) and its supplement (Wrase 1991). These two works included 169 and 9 species, respectively, or altogether 178 species. Guéorguiev (1992) published records for 15 species, based on material in Czech and Bulgarian collections, identified by the late Prof. O. L. Kryzhanovskij and a few Czech specialists. The second most significant contribution to the Bulgarian part of the region appeared to be the catalogue of Guéorguiev and Guéorguiev (1995), in which 61 species in total were mentioned. From the beginning of the XXI century until the present, only scanty information has been added: Guéorguiev and Muilwijk (2000) – 2 species, Guéorguiev and Muilwijk (2001) – 2 species, Guéorguiev (2001) – 1 species, Guéorguiev (2011) – 2 species and Guéorguiev and Kostova (2011) – 1 species. However, among the eight taxa most recently recorded are the only local endemics known from the study area: Cymindis (Paracymindis) vassili Guéorguiev, 2001 and Duvalius (Biharotrechus) bekchievi Guéorguiev, 2011.

Up to now, records from the Turkish section of Strandzha Mt. were largerly lacking. Data from there were published only by Battoni and Vereschagina (1984) - 2 species of Calathus s.str. Bonelli, 1810, as well as by Guéorguiev (2011) and Lapeva-Gjonova et al. (2011) - for a species of Abax Bonelli, 1810 and a species of Paussus Linnaeus, 1775, respectivelly.

The aim of this study is to expand the scarce information available on the carabid beetle fauna of the Strandzha Mountain and adjacent Black Sea Coast.