Diversity of long-legged flies (Diptera, Dolichopodidae) of the BalkanMountains (Bulgaria and Serbia)

The present paper gives information about 61 dolichopodid species distributed in the Balkan Mountains, Bulgaria and Serbia. Twenty-two species, collected from 13 localities, are new to the Balkan Mountains and seven of them (Dolichopus longicornis, Hercostomus chetifer, Medetera pallipes, M. muralis, Neurigona quadrifasciata, N. pallida and Sciapus costea) are new to the fauna of Bulgaria.Medetera pallipes and Sciapus costea are also new to the Balkan Peninsula. Thus, the total number of known species of the family Dolichopodidae for Bulgaria increases to 204.


Introduction
The dolichopodid fauna of the Balkan Mountain range (Stara Planina Mts) has not been subject of special study up to now. Some authors gave separate reports from the Balkan Mountains: Beschovski (1964Beschovski ( , 1967Beschovski ( , 1971 and 2013) listed nine species, Beschovski & Dzhambazhov (2002) reported one species, Olejniček & Barták (1997) listed one species from Dolni Chiflik, Grichanov (2016) recorded 24 species from the Serbian part of the Stara Planina Mts, while Kechev (2017) reported seven dolichopodids collected from the Sinite Kamani Natural Park and Yantra River near Veliko Tarnovo.
The main purpose of this paper is to provide new records of Dolichopodidae for the Stara Planina Mts and to make a review of the known species of the family for the mountain up to now.

Material and methods
The material for the present work was collected by means of sweep net by the author and by means of Mal-aise traps by M. Langourov, T. Ljubomirov and I. Todorov from 13 localities in the studied area (Fig. 1). After collection, the adults were put in vials containing 75% ethanol. The species were sorted in the laboratory, using a stereo microscope Carl Zeiss. For the determination of dolichopodids were used identification guides by Parent (1938), d'Assis Fonseca (1978, Grichanov (2007) and Negrobov & Stackelberg (1969). The faunistic list includes the following information: name of the species, material (male and female) and site of collection.

Balkan Mountains
The Balkan Mountains ( Fig. 1) (Galabov, 1966;Glovnya & Blagoeva, 1982;Hubenov, 1997), also called the Balkans, is a mountain range situated in the eastern part of the Balkan Peninsula. The Balkan range runs 557 km from the Vrashka Chuka Peak on the border between Bulgaria and Serbia eastward through central Bulgaria to Cape Emine on the Black Sea Coast. Geologically, the Balkan Mountains are a mountain chain of fold mountains, a "young" part of the Alpine-Himalayan chain that stretches across most of Europe and Asia.
The Stara Planina (Balkan) range can be divided into three sections: The Western Stara Planina extends from Vrashka Chuka to the Botevgrad Pass (Arabakonak) with a total length of 190 kilometres. The highest peak is Midzur (2169 m a.s.l.).
The Central Stara Planina runs from the Botevgrad Pass to the Vratnik Pass with a length of 207 kilometres. Botev Peak, the highest peak of the mountain (2376 m a.s.l.) is situated in this section.
The Eastern Stara Planina extends from the Vratnik Pass to Cape Emine with a length of 160 kilometres. The highest peak is Balgarka (1181 m a.s.l.).

Discussion
This paper presents information about 61 dolichopodid species, belonging to twenty-two genera and nine subfamilies found in the Balkan Mountains.  (Kechev et al., 2014). Three years later, Kechev (2016) reported another male specimen from the same mountain and locality very close to the first one. This work gives three new localities of this species in the Balkan Mountains, collected at the same altitude as the type locality. The species Sciapus costae is known only from Italy, France, Morocco and Tunisia . This survey expands the area of distribution of the species and provides the easternmost locality of S. costae so far.
The dolichopodids inhabit mostly humid places and all localities of collection in this survey, except Gavril Genovo, are in the vicinity of rivers and streams in the Balkan Mountains. The species found in Gavril Genovo are collected from an oak forest with lower humidity.
The study of predatory flies of the family Dolichopodidae in the Balkan Mountains is still insufficient and new surveys are needed. This work gives base for further investigations and it is probable that the real number of dolichopodids in this region will reach 140-150 species or more.