New data about Bulgarian ground beetles from subfamilies Nebriinae, Carabinae and Cicindelinae (Coleoptera: Carabidae)

Bulgarian ground beetle (Coleoptera: Carabidae) fauna is relatively well studied but there are still many species and regions in the country which are not well researched. The present study aims at complementing the data about the distribution of the carabids from the subfamilies Nebriinae, Carabinae and Cicindelinae, which contain some of the most attractive Palaearctic carabids. Currently, 13 species of Nebriini, ten species of Notiophilini, one species of Cychrini, 28 species of Carabini and 15 species of Cicindelini are known to occur in Bulgaria. The paper gives new information and new records on 37 carabid species and 25 zoogeographical regions in Bulgaria. Beetles are collected in the period from 1976 to 2021 by different collectors and sampling methods. Six species are recorded for the first time in different regions. Four species are reported for the second time in the regions where they have currently been collected. Fourteen species haven’t been reported for more than 20 years from the Middle and Western Stara Planina Mts, Western Bulgaria Region, Kraishte Region, Boboshevo-Simitli Valley, Vitosha Mts, Plana Mt, Lyulin Mts, Rila Mts and Pirin Mts.


Introduction
Ground beetles (Coleoptera: Carabidae) represent one of the largest beetle families with cosmopolitan distribution and with decisive importance for the functioning of ecosystems. The representatives of the studied tribes Nebriini, Notiophilini, Cychrini, Carabini and Cicindelini are among the most attractive Palaearctic carabids, and often occur in many collections. In Bulgaria, most of these beetles are montane and forest dwellers or intra-and extrazonal ecotone and riparian species (e.g. Kryzhanovskĳ, 1983). They are mostly stenotopic or polytopic, nonflying zoophages, adapted to more mesophilic conditions, which is limiting their mass spreading and survival in anthropogenically modified ecosystems (e.g. Kryzhanovskĳ, 1983). Probably, due to that fact, there are still many regions and taxa continuing to surprise us with new records.
Ground beetles are relatively well studied in Bulgaria, but many regions are still poorly researched, and there are still many gaps in our knowledge, especially about the endemic taxa. According to the last edition of the Palaearctic Catalogue of the Ground Beetles, in Bulgaria currently 12 species of Nebriini, ten species of Notiophilini, one species of Cychrini, 24 species of Carabini and 16 species of Cicindelini are known (Löbl & Löbl, 2017). However, according to our own recent estimations (Teofilova & Guéorguiev, unpublished results) these numbers are not accurate, because Cicindela (Sophiodela) virgula Fleutiaux, 1894 never occurred in Bulgaria, but is included in the Palaearctic catalogue (probably by a technical mistake). Furthermore, Leistus (Leistus) (Guéorguiev & Guéorguiev, 1995a;Turin et al. 2003;Teofilova et al. 2020;Teofilova & Guéorguiev, unpublished results). Therefore, the total number of the species currently known in Bulgaria should be 13 species of Nebriini, ten species of Notiophilini, one species of Cychrini, 28 species of Carabini and 15 species of Cicindelini.
The present study is the last part from the complex work concerning the unpublished data about Bulgarian carabids (Teofilova, 2021a(Teofilova, , 2021b(Teofilova, , 2021c(Teofilova, , 2021d. It aims at complementing the data about the distribution of the ground beetles from the subfamilies Nebriinae, Carabinae and Cicindelinae in Bulgaria by adding new records for 5% of the 747 species in Bulgarian carabid fauna (Teofilova & Guéorguiev, unpublished results), collected in 25 zoogeographical regions and subregions (using the same zoogeographical division as in the last catalogue of Bulgarian carabids (Guéorguiev & Guéorguiev, 1995a).

Material and methods
The majority of the material for this study came from a field work carried out in different localities in Bulgaria in the period from 1976 to 2021. This material was collected through different sampling methods, such as handpicking, pan, Malaise, or pitfall trapping, and has not been published so far. All specimens are stored in the author's collection in the Institute of Biodiversity and Ecosystem Research (BAS, Sofia).
The The material was determined by the author unless otherwise noted in the text. All specimens determined by others were re-examined by the author. The nomenclature follows the last edition of the Catalogue of the Palaearctic ground beetles (Löbl & Löbl, 2017).

Discussion
The present study provides some novelty about the carabid fauna of Bulgaria, in particular, of the tribes Nebriini, Notiophilini, Cychrini, Carabini and Cicindelini. They are well studied in Bulgaria, and have a great number of species of conservation value (endemic, relict, rare and two protected species). Despite that fact, this paper gives some new data on their distribution.
Six of the presented species are recorded for the first time in different regions in Bulgaria (Fig. 1 Four species are reported for the second time in the regions where they were currently collected (Fig. 1). Cicindela sylvicola is now reported for the first time in Eastern Balkan Mts, since 1904 (Apfelbeck, 1904). Notiophilus palustris is reported only by Stoyanov and Penev (2004) for the Vitosha Mts. Cicindela campestris and Cylindera germanica haven't been reported for the Lyulin Mt, since Kodzhabashev & Mollov (2000).
Fourteen species haven't been reported for more than 20 years from the Middle and Western Balkan Mts, Western Bulgaria, Kraishte Region, Boboshevo-Simitli Valley, Vitosha Mts, Plana Mt, Lyulin Mts, Rila Mts and Pirin Mts (Fig. 1). Guéorguiev & Guéorguiev Fig. 1. Map of the regions where new data are recorded, with a respective number of the established species. Some of these newly rediscovered species are quite common in Bulgaria and their long-time absence in the given regions is probably due to the lack of more recent research (e.g. Cicindela campestris, Carabus coriaceus and Notiophilus rufipes), since many areas in the country are missing contemporary information about their carabid (or any) fauna. Other species are relatively rare or stenotopic and do not fall in mass collections (e.g. Carabus montivagus, Leistus spinibarbis and Nebria jockischii).
During the research some interesting or confirmative data were obtained. Rare stenotopic forest mesophile Leistus magnicollis was found in the forest ecotone near sparsely vegetated stony habitat; included in the Red Data Book of the Republic of Bulgaria as vulnerable (Guéorguiev, 2015) Carabus scabrosus was also established in some ecotone habitats; mesophilous nature of Leistus spinibarbis and Carabus hortensis was confirmed, as they were found in beech forests; stenotopic hygrophilous mountain species Nebria gyllenhali and N. jockischii were collected near river on 1430 m a.s.l., and on 1500-1600 m, respectively; conservationally significant forest mesophile and indicator Carabus intricatus (IUCN 2021 -NT) was collected in different typically montane localities; rare steppe species Carabus torosus was found on places where it is known it occurs; rare Carabus cavernosus was observed in open subalpine habitat; relict montane species Nebria gyllenhali and Carabus hortensis were collected in their typical places of habitation. Cylindera germanica is widespread but rare in Bulgaria, thus every record of the species is valuable.
Although the ground beetle fauna of Bulgaria is relatively well studied, there are still some regions representing "white spots" in relation to the knowledge about their carabid species composition and community structure (e.g. many different parts of the Danubian Plain and Balkan Mts, Pre-Balkan Region and Sub-Balkan Valleys, Sakar Mts, some mountains near Sofia, Mesta River Valley), and these areas deserve some enlightening in relation to their faunas. More complete knowledge of the diversity of the studied group in the country could be revealed only after carrying out further research in the poorly-examined regions.