Additions to the list of Finnish Bibionomorpha (Diptera, Nematocera)

Abstract A total of 12 gnat species are reported for the first time from Finland (3 Cecidomyiidae, 1 Keroplatidae, 8 Mycetophilidae), and the occurrence of Macrocera nigropicea Lundström in Finland is verified. All material was collected from the Finnish Lapland, mainly from the north boreal ecoregion. Two of the recorded species are likely to be pyrophilous, associated with forest fire sites. A photo of the ventral appendage of the gonocoxite of Brevicornu setigerum Zaitzev is provided for the first time. The male hypopygium of Mycetophila haruspica Plassmann is redescribed.


Introduction
With over 52000 species globally, nematocerans or lower Diptera are one of the most species-rich insect groups in the world (Pape et al. 2009). Within Nematocera, the most successful terrestrial group is the Bibionomorpha, including a majority of the saproxylic, fungivorous and herbivorous species (e.g. Mycetophilidae and Cecidomyiidae, Marshall 2012). As in many other biotic groups, Fennoscandian or North European bibionomorphans are perhaps the best known on the globe, especially regarding fungus gnats (or Sciaroidea, excluding Sciaridae). Despite the taxonomic and faunistic tradition starting from the 18th century (see Kjaerandsen et al. 2007b), species are continually added to the Nordic list Rindal 2012, Jakovlev et al. 2014), including species new to science (e.g. Kjaerandsen et al. 2009, Salmela and Suuronen 2014. No less than 915 fungus gnat species are currently known from the Nordic countries and Russian parts of Fennoscandia (Karelia and Murmansk oblast), consisting of approximately 83 % of the total European fungus gnat fauna (Kjaerandsen 2015). Nevertheless, at least 100 Fennoscandian fungus gnat species await formal naming and description (Kjaerandsen J., Polevoi A., Søli G., Salmela J., in prep.), raising the total number of species occurring in the area to around 1000. Non-herbivorous, or fungivorous and saproxylic gall midges (Cecidomyiidae) are far more poorly known than fungus gnats. In their recent monographs on the Nordic fauna, Mathias and Catrin Jaschhof (Jaschhof andJaschhof 2009, Jaschhof andJaschhof 2013) have described dozens of new species and have much advanced the faunistic knowledge on Lestremiinae and Porricondylinae. For example, the number of Finnish Cecidomyiidae have increased from 136 (Hackman 1980) to 356 (Jaschhof et al. 2014), mainly due to taxonomic and faunistic work performed during the last ten years. However, both Lestremiinae and Porricondylinae should still be considered as poorly known groups, and further additions to the Nordic and Finnish lists are expected.
A list of Finnish Diptera was recently published (Kahanpää and Salmela 2014). In the present paper, 12 species was added to this list (3 Cecidomyiidae, 1 Keroplatidae, 8 Mycetophilidae) and the occurrence of one keroplatid species that was erroneously deleted from the Finnish list was confirmed. Thus, the number of Finnish fungus gnats and gall midges now totals 772 and 359 species, respectively.

Materials and methods
All material reported here was collected from Finnish Lapland (Fig. 1). Lapland is an administrative area, covering a land area of ca. 100k km . The SW corner of the area, close to the Baltic Sea, is middle boreal. The central part of Lapland is north boreal: coniferous forests prevail in the landscape, but there are isolated tree-less fells. Northernmost Lapland is an oroarctic area, sometimes called subalpine ecoregion. Fells and mountain birch forests prevail; isolated pine forests occur in some river valleys. The length of the thermal growing season (i.e. the number of days with the average temperature greater than + 5 C degrees after snow melt) is ca. 140-150 days in the middle boreal and ca. 105-110 days in the subalpine ecoregion (http://ilmatieteenlaitos.fi/terminenkasvukausi, website accessed28.4.2015).
All material is deposited in the private collection of Jukka Salmela, Rovaniemi (JES). All specimens are stored in 70 % ethanol, kept in 2 ml plastic vials with screw cap and a rubber o-ring seal. Hypopygia of some specimens are kept in separate 0,5 ml microvials in glycerol.
Layer photos were taken using an Olympus E520 digital camera, attached to an Olympus SZX16 stereomicroscope. Digital photos were captured using the programmes Deep Focus 3.1 and Quick PHOTO CAMERA 2.3. Extended depth of focus images were reconstructed in the program Combine ZP.

Distribution
European. The species (Fig. 2) was described from Sweden, (Tyresta) as Gongromastix incerta (Jaschhof 2002), and was later transferred to a monotypic genus Eomastix (Jaschhof and Jaschhof 2009). The species is known from Norway and Sweden, from a single site in both countries (Jaschhof and Jaschhof 2009). The Finnish locality is in Urho Kekkonen National Park, in the north boreal zone, close to the Russian border.

Ecology
Larvae of Lestreminae are perhaps mostly saproxylic (Jaschhof and Jaschhof 2009). The species is most likely to be pyrophilous, requiring or preferring forest fire areas. In Sweden, the species was collected from site that had experienced forest fire roughly one year earlier (Jaschhof and Jaschhof 2009). The Finnish collecting site is an oldgrowth burnt forest, dominated by pine (Pinus sylvestris), with scattered spruce (Picea abies) and birch (Betula sp). The forest fire site (Fig. 3) is circa 34 ha in area, and the fire was ignited by lightning in late July 2013. The species seems to have rather long flying season, from June to August.

Distribution
Holarctic. The species is known to occur widely in the Nearctic region, but in the Palaearctic recorded only from southern Sweden (Jaschhof and Jaschhof 2009).

Distribution
European. The species was described recently from southern Sweden, Uppsala and Tyresta (Jaschhof and Jaschhof 2013), no other records are available. The Finnish locality is in SW Lapland, middle boreal ecoregion.

Ecology
The holotype specimen was collected from an "open woodland with old oaks" (Jaschhof and Jaschhof 2013). The Finnish sampling site is a rich fen, surrounded by young deciduous forest. Larvae of Porricondylinae midges are terrestrial mycelium feeders, living on detritus and dead wood (Jaschhof and Jaschhof 2013).

Distribution
European. The species (Fig. 4) was described from France (Latreille 1805) and has been later recorded from Great Britain, Central and North Europe (Matile 1975, Chandler 1991Chandler 2004. The species seems to be rather rare throughout its range (Hedmark 2004, Chandler 1991, Ševčík and Kurina 2011b. In Sweden the species is very rare, known from the southern and central parts of the country, but it has probably vanished from four out of six of its previously occupied biogeographical provinces (Cederberg et al. 2010).

Ecology
Immature stages are unknown, but Orfeliini larvae are predaceous (Marshall 2012). Asindulum nigrum has been collected from calcareous wetlands (Chandler 1991, Hedmark 2004) and adult flies have often been observed visiting flowers, such as Apiaceae and Saxifraga hirculus (Bechev 2010). Finnish collecting site is a calcareous rich fen with iron-rich seepages (for a detailed description of the habitat, see .

Conservation
The species is red-listed in Great Britain (NT, Falk and Chandler 2005) and Sweden (VU, Cederberg et al. 2010).

Distribution
Holarctic. The description of the species (Fig. 6) was based on material collected from three Nearctic sites in Arizona, British Columbia and Ontario (Zaitzev 1982). Later the species has been recorded from the Russian Far East (Zaitzev 2006), France, Switzerland (Chandler 2004) and the Czech Republic (Ševčík 2005). New for the Fennoscandian fauna.

Ecology
Immature stages are unknown, but Sciophila larvae are fungivorous, living on the surfaces of agaric and polyporous fungi (Ševčík 2010), rarely on Pezizales (Jakovlev 2011). Finnish locality (Fig. 7) is a iron-rich spring-fed brook on an ecotone between a pine mire and a luxuriant riparian forest.   (Zaitzev 1982) and Czech Republic (Ševčík 2005). Record from East Palaearctic (Chandler 2004) refers to Kola Peninsula, so it is not an additional area of distribution (P.J. Chandler, pers.comm.).

Ecology
Immature stages are unknown, but S. fridolini is presumably a woodland species (Falk and Chandler 2005). The Finnish collecting site is an alpine wetland along a headwater stream, characterized by Carex tussocks, Viola biflora and sparse mountain birch forest.

Distribution
European. In his original description, Zaitzev (Zaitzev 1982) assigned S. spinifera (Fig.  8) as a Finnish species, the holotype specimen was collected by Richard Frey from a place named "Opariornia". There is, however, no such place in Finland, and later the holotype was interpreted as a Swedish specimen, collected from Övertorneå (Kjaerandsen et al. 2007b, misspelled by Zaitzev), on the Swedish side of the River Tornio between Finland and Sweden. In addition to Sweden, the species is known from southern Norway (Økland and Zaitzev 1997) and Switzerland (Chandler 1998).

Ecology
Immature stages are unknown, but S. spinifera is presumably a forest-dwelling species (Økland and Zaitzev 1997). Finnish sampling sites are either old-growth, sprucedominated moist forests (two sites) or a swampy birch forest.

Distribution
European. A rarely collected and poorly known species, reported from Czech Republic (Ševčík 2004) and Russian Karelia (Jakovlev et al. 2014). The Finnish collecting site reported here is located in SW Lapland, middle boreal ecoregion.

Ecology
Larvae of Allodia are likely to be fungivorous, see discussion in Jakovlev et al. 2014. The Finnish locality is a herb-rich riparian forest, dominated by deciduous trees.

Distribution
European. A poorly known and rarely collected Fennoscandian species (Fig. 9). The species was described by Zaitzev (in Zaitzev and Polevoi 1995), based on a holotype male collected from Kivach Nature Reserve, Russian Karelia. Recently, the species was observed from Alta in northern Norway (Søli and Rindal 2012).

Ecology
Immature stages are unknown, but Brevicornu larvae are most likely associated with microfungi in dead wood and soil litter (Jakovlev 2011). The species is presumably a forest-dwelling fungus gnat; at least, the Norwegian sampling site was a mixed forest (Ekrem et al. 2012). The Finnish locality is a swampy birch forest in the subalpine ecoregion.

Ecology
The species has been collected from both subalpine and boreal ecoregions, but detailed habitat descriptions are lacking in the literature. Finnish sampling sites are small lotic water bodies surrounded by old-growth boreal forests.

Taxon discussion
The original description of M. haruspica is rather uninformative, barely sufficient for identification purposes (Plassmann 1990, fig. 8). Proper redescription of this species is a b c d beyond the scope of this manuscript, but the morphology of the male hypopygium is reviewed here. The ventral lobe of gonostylus (vl gst, Fig. 11) has a conspicuous, helmet-like rounded lobe on dorsal margin and a small, hyaline spine next to it. Another prominent feature of vl gst is a long ventro-caudal spine, slightly bent beyond its midpoint (Fig. 11). Dorsal lobe of gonostylus (dl gst, Fig. 11) has a narrow, rounded lobe on the dorsal margin. The general shape of aedeagus is cordate, caudally tapering, apex incised and apical corners with a pair of narrow, hyaline lobes (Fig. 11c). 9th tergite is about as long as gonocoxite. Ventral margin of gonocoxites is undulating (Fig.  11d). Based on the male hypopygium, the species is easy to separate from the other members of the vast genus Mycetophila.

Distribution
European. The species (Fig. 12a, c) was recently described from the Gemer region in the central part of Slovakia (Ševčík and Kurina 2011a). No other records are available. New for the Fennoscandian fauna.

Ecology
The holotype male was collected from a "spring area in a young spruce forest, 1230 m (above sea level)" Ševčík and Kurina 2011b). Finnish locality is a herb-rich riparian forest, dominated by deciduous trees.

Taxon discussion
The species is quite close to M. lastovkai Caspers, 1984 (Fig. 12b, d), a species that has been in the Nordic region reported from Sweden, Norway and Denmark (Kjaerandsen 2015). Nordic material of M. lastovkai should be re-examined in order to check the potential confusion with M. gemerensis.