A new Neoplatyura Malloch from Finland (Diptera, Keroplatidae)

Abstract The genus Neoplatyura Malloch is globally represented by 50 species, of which four are European species. In this article a new European Neoplatyura from Finland is described. The new species, Neoplatyura noorae Salmela, sp. n. is a dark brown species with tibial bristles arranged in rows. The new species is here reported from seven localities in Finnish Lapland. Based on available data, the new species occurs in mires, especially in calcareous rich fens.


Introduction
The fungus gnat group (Diptera, Sciaroidea excluding Sciaridae) is a species rich nematoceran group belonging to the infraorder Bibionomorpha (Søli et al. 2000, Wiegmann et al. 2011. In Europe, fungus gnats seems to display an anomalous richness gradient being most diverse in the northern boreal region (e.g. Jordal 2007, Kjaerandsen et al. 2007). No less than over 900 species occur in Fennoscandia, of which 768 have been reported from Finland (Kjaerandsen 2012, Jakovlev et al. 2014. Fungus gnats are mostly forest-dwelling insects (Søli et al. 2000), but some species are are usually found on wetlands (e.g. Jakovlev et al. 2014 and references therein). However, the fungus gnat fauna of mires and other wetlands is still poorly known in Fennoscandia, despite the fact that wetlands may cover extensive ares (30-70% of the land area) in the northern parts of the region. In this article we describe a new keroplatid fungus gnat species belonging to the genus Neoplatyura Malloch from Finnish Lapland that seems to occur exclusively in mires.
The genus Neoplatyura Malloch, 1928(Malloch 1928 belongs to the family Keroplatidae and its subfamily Keroplatinae (tribe Orfeliini). There are 50 described Neoplatyura species, of which 20 are Australasian, 11 Palaearctic, 10 Neotropical, 5 Afrotropical, 2 Oriental and 2 Nearctic (Evenhuis 2006). So far, none of the species has a Holarctic range and four of the Palaearctic species are present in Europe. Following Uesugi (Uesugi 2002), species of the genus can be distinguished by the following morphological characteristics: branches of medial and cubital veins setulose dorsally; prothoracic spiracle with a row of erect black setae on posterior margin; mediotergite and laterotergite bare. However, there is a wide range of genital structure in species assigned to this genus worldwide and it is probably paraphyletic (P.J. Chandler, pers. comm.). Immature stages of the genus are poorly known, but larvae might be predatory, living in soil, or in fungal sporocarps or in decaying wood (Falk andChandler 2005, Jakovlev 2011).

Materials and methods
All studied specimens were obtained from Malaise trap samples. The Malaise trap model used was made of cloth with black sides and white cover, (length 110, height 140, width 70 cm) and is suitable for collecting low-flying insects, such as many dipterans. The traps were set in the beginning of June and removed from the field in the late August -mid September; collecting jars were emptied at roughly one month intervals. A solution of 50% ethylene glycol + few drops of detergent was used as a preservative in the traps. The collected material was stored in 70% ethanol. The fungus gnats were sorted from the material in the laboratory. The morphological terminology used here mainly follows Søli et al. 2000. Terminology of some special parts of male genitalia is explained in the figures.
Female unknown.

Diagnosis
Dark brown species with unpatterned wings. Apical setae of mid and hind tibiae arranged in rows. Gonocoxite pear-shaped with pronounced, glabrous median lobe. Gonocoxite with a conspicuous dorsal lobe, bearing a comb-like row of short and stout setae. Gonocoxites are widely separated ventrally while the other European species have them fused medially by a more or less wide bridge. Gonostylus finger-like. Based on unpatterned wings, body coloration and structure of male hypopygium, the species is easily distinguished from its congeners.

Etymology
The species is named after MSc Noora-Annukka Vartija, our friend and colleague. Noora Vartija sorted out and recognised this as a possible new species from large masses of Malaise trapped material from Finnish Lapland.

Distribution
European, so far only known from Finland. Most of the collecting sites are in central Lapland, north boreal ecoregion, in Kittilä municipality. There is also a record from southwestern Lapland, mid boreal ecoregion, Tornio municipality.  Neoplatyura noorae Salmela, sp. n., male, wing.

Ecology
Invariably, all collecting sites are pristine boreal peatlands.

Conservation
Six out of seven collecting sites are conservation areas, protected by Nature Conservation Act. The species seems to have restricted occurrence in Finland, both geographically (north Finland) and ecologically (pristine fens), and could perhaps be later classified as a threatened species following IUCN criteria (see e.g. Penttinen et al. 2010).

Taxon discussion
The species is readily distingushed from its European congeners. If added to the key provided by Hutson et al. 1980 (p.37) Neoplatyura noorae Salmela, sp. n. would be keyed out in the first couplet, because it has unpatterned wings (biumbrata (Edwards) with darkened wing tip and a cloud on posterior vein of CuA ) and being dark brown species (the rest of the European species are yellowish). Nearctic species N. pullata (Coquillett) is a dark species, but has Sc ending in C at the level Rs (in N. noorae Sc 2 Figure 3. Neoplatyura noorae Salmela, sp. n., male gonocoxite and gonostylus, lateral view. Abbreviations: d.l.gc = dorsal lobe of gonocoxite, gst = gonostylus, gc = gonocoxite. ending in C before Rs). It should be noted that N. pullata is only known from a female holotype specimen, collected from USA, California (Johannsen 1910, Evenhuis 2006).

Acknowledgements
English text was checked by John Kramer (Leicester). Peter J. Chandler and Olavi Kurina gave constructive comments and suggestions.