A new species and new records of Molophilus Curtis, 1833 (Diptera: Limoniidae) from the Western Palaearctic Region

Abstract Background Molophilus Curtis, 1833 is the most species-rich Limoniidae genus with a total number of 1006 species and subspecies, from which 97 are recorded in the Western-Palaearctic region so far. However new species are still expected from less investigated regions, like the Balkans or the Eastern Europe. New information In the present article, we desrcibe a new limonid crane fly species, Molophilus balcanicus Kolcsár sp. n. from the Central Balkan area (Bulgaria). This new taxa is closely related to M. serpentiger Edwards, 1938 and M. variispinus Starý, 1971 based on the external male genital structures, but differs from its siblings mostly in the structure of the inner and outer gonostylus. Additionally, a number of species are reported for the first time from various European countries, like M. variispinus Starý, 1971 and M. occultus de Meijere, 1918 from Romania; M. crassipygus de Meijere 1918, M. obsoletus Lackschewitz, 1940 and M. medius de Meijere, 1918 from Greece; M. flavus Goetghebuer, 1920 from Andorra; M. cinereifrons de Meijere, 1920 from Bulgaria and M. corniger Meijere, 1920 from Spain.


Introduction
Molophilus Curtis, 1833 is the most species-rich genus in the Western-Palaearctic region, belonging to Limoniidae (Diptera). The species can be easily identified based on male robust hypopigium. The females are unknown or less studied. So far, there are more than 1000 species and subspecies are described worldwide with an Australasian-Oceanian distribution center (Oosterbroek 2015). At the present 97 species and subspecies are known to occur in the Western-Palaearctic region (Oosterbroek 2015, Starý 2011). In the present study we report 8 new faunistic data from different countries in Europe, and we describe a new species which is closely related to M. serpentiger Edwards, 1938 andM. variispinus Starý, 1971. Both of the two closely related species, M. serpentiger and M. variispinus share a unique feature within the genus Molophilus, the presence of an Sshaped outer gonostylus (Starý 1971b, Starý 1971a, which is highly similar in M. variispinus and M. serpentiger (mostly seen in ventral view) (Kramer 2013). In the frame of the current study we present the habitus, the male hypogium (ventral and lateral view) and the aedeagal complex, both in the case of M. serpentiger, M. variispinus and M. balcanicus Kolcsár sp. n.

Materials and methods
The material was collected by entomological net and UV light trap in Andorra, Bulgaria, Greece, Romania and Spain, beetwen 2010 and 2013. All the material listed here, are stored in 96% ethanol and deposited in the Diptera Collection of the Faculty of Biology and Geology, Cluj-Napoca, Romania. The holotype of the new species is deposited in the Museum of Zoology of the Babeș-Bolyai University (MZBBU), Cluj-Napoca, Romania. The specimens were examined with an Olympus SZ50 dissection microscope. Photos were taken using an Canon EOS 650D digital camera, attached to an Olympus SZ60 stereomicroscope, with a LM Digital SLR Adapter (Micro Tech Lab, Austria). Layer photos were finally combined with the software Combine ZP (Hadley 2011). Thorax. Yellowish orange (Fig. 1a). Frontal parts of the thorax are darker than the back parts, with an evenly transition from yellow to dark orange. The neck (cervix) has its lateral parts black (cervical sclerites). Prescutum and scutum orange, scutellum yellow, pleural part yellow -orange. The coxae and the trochanters are yellowish orange, with long pale setae. The femur, tibia and tarsomeres are absent in the examined material. Wings yellow, wing venation light brown, covered by a densely light brown macrotrichia, partly worn out in specimen examined by us. Haltereres are yellow.

Taxon treatments
Abdomen. Dark orange -light brown, tergites mainly dark, anterior sternites lighter than caudal sternites. Both sternites and tergites are covered with long pale setae. Pleural membrane yellow. Hypopigium generally yellow (Fig. 1b, c). 9th tergite covered by long pale setae. The dorsal portion of the gonocoxite is short, rounded in lateral view, the caudal margine is straight, with a darkened inner wedge like projection at the ventral edge, which is striking dark pigmented at the end (ventral (tergal) view - Fig. 1b). Ventral lobe of gonocoxite shorter than dorsal portion and it is rounded at the tip. All parts of gonocoxit are covered by long yellowish setae. Both gonostyli are darkly pigmented. The inner gonostylus has its proximal part very thick, which ventrally narrows and is slightly curved. The outer gonostylus is thick, S-shaped inwards and it is ending in a hook like structure ventrally. The proximal part is stouter and lighter than distally, which widens before the hook like end (ventral view - Fig. 1b). Aedeagus is long, the end reaches the gonocoxite apex. The proximal part is thick which narrows to the distal end. In half of the length of the aedeagus is curved ventrally, after that it turns dorsally (Fig. 1d).

Diagnosis
Small species with yellowish orange general colour, body lenght is 4-4.5 mm and wing length 5 mm (Fig. 1a)

Ecology
Only one specimen was collected in a beech forest, close to a small brook at 1100-1200 m. The valley of the brook was dominated by medium to large sized rocks, along with thick layer of accumulated leaf litter.

Taxon discussion
The new species is very close to Molophilus serpentiger and M. variispinus, but differs from both sibling species by the thick outer and inner gonostylus. Both of the two already known sibling species have thin outer gonostylus without hook like end (Figs  1c, 2c, 3c). M. balcanicus sp. n. is more close related to M. variispinus, than to M. serpentiger, on the base of the shape of the aedeagal complex (Figs 1d, 2d, 3d). a b c d Figure 3.

Notes
The habitus, the hypopigium and the aedeagal complex of the male are illustrated in Fig. 3.

Notes
First record to Romania.