The ground beetles (Coleoptera: Carabidae) of the Strandzha Mountain and adjacent coastal territories (Bulgaria and Turkey)

Abstract Background The knowledge of the ground-beetle fauna of Strandzha is currently incomplete, and is largely based on data from the Bulgarian part of the region and on records resulting from casual collecting. This study represents a critical revision of the available literature, museum collections and a three years field study of the carabid beetles of the Bulgarian and Turkish parts of Strandzha Mountain and the adjacent Black Sea Coast territories. New information A total of 328 species and subspecies of Carabidae, belonging to 327 species from the region of Strandzha Mountain and adjacent seacoast area, have been listed. Of these, 77 taxa represent new records for the Bulgarian part of the region, and 110 taxa new records for Turkish part of the studied region. Two taxa, one subgenus (Haptotapinus Reitter, 1886) and one species (Pterostichus crassiusculus), are new to the fauna of Bulgaria. Based on a misidentification, the species Apotomus testaceus is excluded from the list of the Bulgarian fauna. Seven species (Carabus violaceus azurescens, Apotomus rufus, Platynus proximus, Molops alpestris kalofericus, M. dilatatus angulicollis, Pterostichus merklii, and Calathus metallicus) are treated as doubtful for the regional fauna, and one (Apotomus rufus) also for the Bulgarian fauna. Altogether, 43 taxa collected in the Turkish part of the region are new for European Turkey. New taxa for Turkey are the genera Myas and Oxypselaphus, the subgenus Feronidius, and nine species and subspecies (Carabus granulatus granulatus, Dyschirius tristis, Bembidion normannum apfelbecki, B. subcostatum vau, Acupalpus exiguus, Myas chalybaeus, Oxypselaphus obscurus, Pterostichus leonisi, Pt. melas). In addition, there are a further seven species that are here confirmed for Turkey.


Introduction
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 speciesrich 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 collecting methods used for the field study were as follows: manual collection under tree bark and stones and substrate sifting (soil, leaf litter, etc.) by sifter with aperture dimensions of 6 and 10 mm. The material was checked directly in the field or placed in Winkler-Mokzarski extractors. Pitfall traps comprising 500 ml containers filled with propylene glycol as a preservative, were set in transects in selected sites. Light traps comprised a tower with two types of light sources: 160W MBTF and F8T5 -365 nm. Vacuum sampling from different substrates with a modified leaf blower Partner GBV 325. The material from pitfall traps was collected monthly from May to October 2009. The other methods of collection aim to cover a maximum number of habitats in the region and are non-systematic. Manual sampling, sifting and vacuum sampling were performed in all studied localities during 2009-2011. During the same period, light trapping was used at different localities for 1 -3 days per month, depending on the weather conditions. The collected material was preserved in tubes filled with 70% ethanol. Determination of the species was performed using a Zeiss -Stemi 2000 stereomicroscope. Carabidae voucher specimens collected during this study are deposited at the Department of Zoology and Anthropology, Faculty of Biology, Sofia University.
countryCode: BG; locality: Malko Tarnovo; bibliographicCitation: Guéorguiev (1992: 62) Leistus ( countryCode: BG; locality: Ahtopol; bibliographicCitation: Guéorguiev & Guéorguiev (1995: 72) Notes: We consider that the identification of this taxon may be doubtful. However, we cannot find and revise this material, so the species is tretaed here as questionable for both the regional fauna and the fauna of Bulgaria.
countryCode: BG; locality: Maslen nos Cape; bibliographicCitation: Guéorguiev & Guéorguiev (1995: 72) Notes: The only specimen published by Guéorguiev (1992: 63) has been revised and proved to be Apotomus clypeonitens adanensis Jedlička. Hence, Apotomus testaceus Dejean is removed from both the list of the Bulgarian and Balkan fauna. countryCode: BG; locality: Strandzha; bibliographicCitation: Guéorguiev & Guéorguiev (1995: 198) Harpalus ( Guéorguiev & Guéorguiev (1995: 142) Notes: This record is probably based on mislabelled specimens.  Guéorguiev & Guéorguiev (1995: 134) Notes: This record is probably based on mislabelled specimens. Range (= Stara Planina Mts.). In fact, we consider it highly likely that the mountain which is referred to as Reitter's type locality is Strandzha Mt. However, as we noted in the introduction, the largest area of this massif lies outside Bulgaria and closer to the known area of species distribution, i.e. the surroundings of the Bosphorus. Therefore, the finding near Slivarovo Villlage is certainly the first precise record of P. crassiusculus from Bulgaria.

Molops
Six species (Carabus violaceus azurescens, Platynus proximus, Molops alpestris kalofericus, M. dilatatus angulicollis, Pterostichus merklii, and Calathus metallicus) are considered to be doubtful for the region, though we have revised material of them. The material on which the above species are based, published by Guéorguiev (1992) and/or Guéorguiev and Guéorguiev (1995), is labelled in the same manner, was recorded on the same date (16.7.1933), and was collected by the same collector (K. Tuleshkov). The question arises because all those species being primarily mountain dwellers, have been reported from a region of low altitude. Another doubtful record for the regional fauna, as well as for the fauna of Bulgaria, is Apotomus rufus; we have never seen material of this species from the country. This species has been omitted for Bulgaria in the Palaearctic Catalogue of Carabidae (Wrase 2003).

TURKISH PART OF AREA:
In this area 114 species and subspecies have been confirmed for the Turkish part of the region. Of these, 110 species represent new records for the area, while four species are known from both previous and new records. A total of 43 carabid species and subspecies found in the Turkish part of the study region represent first records for the European part of Turkey. Carabid taxa new to the fauna of Turkey comprise two genera (Myas, Oxypselaphus), one subgenus (Feronidius), nine species and subspecies (Carabus granulatus granulatus, Dyschirius tristis, Bembidion normannum apfelbecki, B. subcostatum vau, Acupalpus exiguus, Myas chalybaeus, Oxypselaphus obscurus, Pterostichus leonisi, Pt. melas). It seems that the ranges of most of these taxa (exept for B. normannum apfelbecki) are confined to the European part of the country and their populations do not extend east of the Bosphorus. It should be noted that one of the species (O. obscurus) was included in the checklist of the caraboid beetles of Anatolia (Casale and Vigna Taglianti 1999), as "? : occurrence in Anatolia doubtful or presumable, but not confirmed". As we have not found any source citing that species for the country, we treat it as new to the fauna of Turkey. Also, there are seven species which were included for Anatolia by Casale and Vigna Taglianti (1999) ("taxa presumably valid or confirmed") but were subsequently not mentioned for Asian Turkey in the Palaearctic Catalogue of Carabidae (Lӧbl and Smetana 2003). These species are: Asaphidion flavipes, Bembidion assimile, B. guttula, B. articulatum, Tachyura parvula, Parophonus maculicornis and Polistichus connexus. We consider that if these species occur in the European territory of the country, they should therefore be considered as taxa confirmed for Turkey.