New and unpublished data about Bulgarian ground beetles from the tribes Pterostichini, Sphodrini, and Platynini (Coleoptera, Carabidae)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 tribes Pterostichini, Sphodrini, and Platynini, containing many diverse, interesting, and endemic species. It gives new records for 67 species and 23 zoogeographical regions in Bulgaria. The material was collected in the period from 1926 to 2021 through different sampling methods. Twenty-three species are recorded for the first time in different regions. Six species are reported for the second time in the regions where they were currently collected. Thirty-one species have not been reported for more than 20 years in Eastern and Middle Stara Planina Mts., Kraishte region, Boboshevo-Simitli valley, Sandanski-Petrich valley, Lyulin Mts., Vitosha Mts., Rila Mts., Pirin Mts., Slavyanka Mts., Thracian Lowland, and Sakar-Tundzha region. New altitude ranges are established for six of the species. The results contribute to the knowledge of the Bulgarian carabid fauna. Currently, 56 species of Pterostichini, 23 species of Sphodrini, and 36 species of Platynini are known from Bulgaria. Acta Biologica Sibirica 7: 125–141 (2021) doi: 10.3897/abs.7.e67015 https://abs.pensoft.net Copyright Teodora Teofilova. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. RESEARCH ARTICLE New and unpublished data about Bulgarian ground beetles from the tribes Pterostichini, Sphodrini, and Platynini (Coleoptera, Carabidae)


Introduction
Ground beetles (Coleoptera, Carabidae) represent one of the largest beetle families with cosmopolitan distribution and great importance for the functioning of ecosystems. The representatives of the studied tribes Pterostichini, Sphodrini, and Platynini are very diverse. Tribe Pterostichini is one of the most species-rich groups of carabids, especially diverse in the Holarctic. Platynini is one of the largest tribes in the world fauna and is especially numerous in the tropics. Sphodrini is a smaller tribe with species distributed mainly in the Palearctic (Kryzhanovskij 1983).
In Bulgaria, most Pterostichini are non-flying zoophages, adapted to more mesophilic forest and montane conditions, and some of them are only locally spread endemics. Platynini are mostly hygrophilous intra-and extrazonal ecotone and riparian species. Unlike Sphodrini, which are adapted for survival in different ecosystems including anthropogenically modified, many Pterostichini and Platynini are stenotopic (e.g. Kryzhanovskij 1983).
Therefore, the total number of species currently known in Bulgaria should be 56 species of Pterostichini, 23 species of Sphodrini, and 36 species of Platynini.
The present study aims at complementing the data about the distribution of the ground beetles from the tribes Pterostichini, Sphodrini and Platynini in Bulgaria by adding new records for 9% of the species in Bulgarian carabid fauna, collected in 23 zoogeographical regions and subregions.

Material and methods
The majority of the material for this study came from field work carried out in different localities in Bulgaria in the period from 1926 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.

Results
The present study is based on various field observations and contains data about 67 Bulgarian carabid species from the tribes Pterostichini, Sphodrini and Platynini, collected in 23 zoogeographical regions and subregions in Bulgaria. Twenty-three species are recorded for the first time in different regions. Six species are reported for the second time in the regions where they were currently collected. Thirty-one species have not been reported for more than 20 years.

Discussion
Twenty-three of the presented species are recorded for the first time in different regions in Bulgaria (Figure 1) Very interesting is the finding of Pterostichus rhilensis in the Predbalkan region, at about 300 m a.s.l. The species is a Bulgarian montane endemic and, so far, it has been collected on altitudes of above 1000 m. The subspecies rhilensis vitosensis is known from the Middle Stara Planina and Vitosha Mts. The other two subspecies rhilensis rhilensis Rottenberg, 1874 and rhilensis kourili Mařan, 1933, are distributed in Southern Bulgarian mountains. The real relevance of these forms is not entirely clear, as is the question of the biogeographical variability of the species, as it has also been stated by the late Prof. O. L. Kryzhanovskij (Kryzhanovskij unpublished results). It is possible that the material from the Predbalkan region has to be attributed to different subspecies. That should be proved by collecting and analyzing additional and more recent material.
New altitude ranges are found for another five species, but those were expanding upwards. Poecilus anatolicus is reported here from an altitude of 790 m in Sredna Gora Mts. while it was so far known from up to 430 m in the Eastern Rhodope Mts. (Teofilova and Kodzhabashev 2020). Olisthopus fuscatus was so far known only from the Black Sea coast up to 50 m (Hieke and Wrase 1988;Wrase 1991;Guéorguiev and Guéorguiev 1995a;Teofilova et al. 2012, Kostova andGuéorguiev 2016;Kryzhanovskij unpublished results); it is recorded here from 230 m in the Sandanski-Petrich valley. The range of Agonum micans lifted in height with only 50 m, to 300 m, as it was pre- viously known from 250 m in the same zoogeographic region (Vasilev and Necheva 1985;Guéorguiev and Guéorguiev 1995a). Pterostichus macer is recorded here from 750 m in the Lyulin Mts., as it was previously known up to 600 m . Molops robustus parallelus was previously known from up to 1000 m , and here is reported from 1200 m in the Vitosha Mts. Since most of the material is relatively old, it would be speculative to predict if these new findings concern global environmental changes and reflect the respective responses of the animals, but such trends have been previously reported in Bulgaria (Teofilova 2017).

Conclusion
The present study provides some novelty about the carabid fauna of Bulgaria and more precisely for the tribes Pterostichini, Sphodrini and Platynini, containing many diverse, interesting and endemic species. Although the ground beetle fauna of Bulgaria is relatively well studied, there are still some regions representing "white spots" regarding the knowledge of their carabid species composition and community structure (different parts of the Danubian Plain and Stara Planina Mts., Predbalkan and Podbalkan regions, Sakar Mts., some mountains near Sofia, Mesta river valley). A more complete knowledge of the diversity of the carabids in the country could be revealed only after carrying out further studies in these poorly-examined regions.