New records of Dasyhelea Kieffer , 1911 from Sweden , with descriptions of two new species ( Diptera : Ceratopogonidae )

Based on intensive collecting from various sites in Sweden, the genus Dasyhelea Kieffer, 1911 was reviewed and the number of species now known from the country increased from five to twenty. Among the new species recorded there are two species described as new to science, D. dominiakae sp. nov. and D. gothlandica sp. nov., both in the subgenus Dicryptoscena Enderlein, 1936. The following subgenera are now documented from Sweden: Dasyhelea, Dicryptoscena, Pseudoculicoides Malloch, 1915, Prokempia Kieffer, 1913 and Sebessia Remm, 1979, the two latter subgenera being reported for the first time.


Introduction
The genus Dasyhelea Kieffer, 1911 is classified in the subfamily Dasyheleinae Lenz, 1934 and is cosmopolitan in distribution.More than 600 Dasyhelea species are known, representing one-tenth of all described Ceratopogonidae species in the World (Borkent 2015).The highest diversity is described from large countries in the northern hemisphere, i.e., China, USA and Russia (Borkent 2015).The immature stages of Dasyhelea inhabit a wide range of moist and terrestrial habitats, like peat bogs (Domniak & Szadziewski 2006), rockpools (Wirth 1978), plants of Nepenthes Linnaeus (Wirth & Beaver 1979), tree sap (Domniak 2005) and in mushrooms (Graves & Graves 1985).The short-lived adults (Zilahi-Sebess 1931) are often found in or around the vegetation near the breeding sites (Waugh & Wirth 1976).The structure of the mouthparts in both sexes is similar, i.e., reduction of both mandibles and maxillae (Glukhova 1981), and both males and females feed on nectar and honeydew and according to Wirth (1956) they can act as pollinators of plants such as rubber trees (Hevea brasiliensis (Willd.ex Adr.Juss.)).
The most recently described ceratopogonid species from Sweden, which are still valid, are Forcipomyia squamigera Kieffer, 1916 andBezzia pilipennis Lundström, 1916.Reports thereafter added more species records for the country, resulting in a record list of approximately one hundred species of Ceratopogonidae for Sweden (Rehnberg & Brodin 2010;Nielsen et al. 2010;Szadziewski et al. 2012).This may be compared to 184 species in Estonia, 211 in Poland and 256 in Germany (Szadziewski et al. 2012), which indicates that Sweden might have been undersampled historically compared to some other countries.Efforts were therefore made in order to more carefully examine the Swedish diversity using recently trapped material from various sites.The Swedish Dasyhelea include five species previously recorded from Sweden: D. pallidiventris (Goetghebuer, 1931), D. corinneae Gosseries, 1991, D. turficola Kieffer, 1925, D. modesta (Winnertz, 1852) and D. notata Goetghebuer, 1920 (Dominiak & Szadziewski 2010).With this report the number of Dasyhelea species in Sweden increases to 20, a low number compared to the more than 60 species recorded from the rest of Europe (Szadziewski et al. 2012).

Material & Methods
The specimens in this study were collected from Djäknabygds Bokbacke during the summer of 2005, from Limhmans kalkbrott (limestone quarry) during the summer of 2009, and various other localities in Sweden during the spring and summer of 2011.Specimens were collected in Malaise traps and in sweep nets.At the lab they were stored in 80% ethanol in deep freezers.After sorting and preliminary identification, the whole body was cleared using Proteinase K as part of DNA extraction and sequenced for mitochondrial cytochrome I (COI) according to the methods described in Strandberg & Johanson (2010).The COI sequences were used to associate males and females using MEGA 5.2.2 (Tamura et al. 2011), applying the settings in Stur & Borkent (2014).The head, wings and abdomen/genitals from the thorax and one leg from each leg pair were mounted under separate cover slips on microscope slides using Euparal as permanent mounts.Specimens from Limhamns kalkbrott and Bunkeflostrand are stored at the Museum of Zoology, Lund University, Sweden (MZLU) while the rest are deposited at the Department of Zoology, Swedish Museum of Natural History (NHRS).
In the descriptions, specimens were measured for each character and ratios and measurements of the antennae (AR), palpi (PR (III) ), wings and costal vein (CR) were obtained following the methods described by Dominiak (2012).Measurements are given for the holotype as well as the range of variation in each character for the paratypes (n = number of specimens examined).

Biology
Specimens were collected on mire close to a lake during mid June.Previously D. bensoni has been collected from the end of May to mid July (Edwards 1933;Remm 1979).

Biology
The specimens were collected in an area with shore meadows on the west coast in the south of Sweden.
The larva inhabits shallow water bodies; both natural and artificial and preimaginal stages are very tolerant of desiccation and temperature fluctuations (Zilahi-Sebess 1931;Valkanov 1941;Disney 1975).

Remarks
The male keys out as D. bilineata in Dominiak (2012).The associated female has the subgenital plate with broad lateral processes and a more hearth-shaped notum in contrast to the isosceles triangularshaped notum of D. bilineata shown in Dominiak (2012).

Biology
The specimen was collected in a marsh situated between two lakes with water flowing through.Last instar larvae and pupae of Dasyhelea caesia have previously been collected from a small body of water and the littoral zone of lakes in Russia during July (Brodskaya 1995;Przhiboro 2005).

Biology
Specimens were collected on mire next to a lake from the beginning of June to the beginning of July.

Biology
Larvae of D. flavifrons can be found in tree sap or tree holes.Flight period May-October (Dominiak 2012).

Remarks
The previous listing of this species as present in Sweden is doubtful as it has only been reported in Rehnberg & Brodin (2010), based on D. versicolor (Winnertz, 1852) as listed in Szadziewski et al. (1997).We were unable to verify previous records.

Biology
Dasyhelea pallidiventris is considered a haloxene, and the larvae inhabit inland saline habitats and the littoral zone of lakes (Szadziewski 1983).Previously recorded from Norrtälje in east-central Sweden (Dominiak & Szadziewski 2010).

Biology
Specimens collected on a heath with old beeches.

Biology
This specimen was collected at a peat bog in the beginning of August.

Biology
These specimens were collected in a marsh and in a seasonally flooded area next to a lake.D. arenivaga is known to visit umbelliferous and tamarisk flowers (Dominiak & Szadziewski 2010).

Biology
The specimens were collected in a small village garden.Larvae can be found in both fresh and salt-water habitats and are common on inland saline meadows in Poland (Dominiak 2012).

Remarks
The association of the sexes made by Remm (1972) has previously been considered incorrect.The associated female probably belongs to D. unguistyla Remm, 1972(Dominiak & Szadziewski 2010)

Biology
The only specimen recorded from Sweden was collected at Antjärn in August (Dominiak & Szadziewski 2010).

Biology
Specimens collected on mire in the north of Sweden and from the vegetation in a marsh in the southeast of Sweden.It is reported as a spring-summer species, most common between May and June (Remm 1962).

Biology
Dasyhelea turficola larvae are known to inhabit peat bogs and moist soil close to fresh and salt-water bodies.Adults of the species visit umbelliferous flowers (Dominiak 2012).Previously, D. turficola have been collected in Johannisfors (Dominiak & Szadziewski 2010).

Biology
Adults of this species are known to visit umbelliferous flowers (Dominiak 2012).

Biology
These specimens were collected close to a pond in an old limestone quarry in the south of Sweden.

Biology
The specimens were collected from a small peat-bog in the middle-east of Sweden and from an old limestone quarry in the south of Sweden.Preimaginal stages have previously been found in and around a spring (Spâtaru & Damian-Georgescu 1970).

Diagnosis
The male resembles those of D. notata in the morphology of the genitalia, particularly by the presence of a pair of horn-like projections on the posterior margin of sternite 9.It is distinguished from D. notata in having an additional triangular projection on each lateral side of the posterior margin of sternite 9.

Etymology
This species is named after Dr. Patrycja Dominiak for her contributions to our knowledge of European Ceratopogonidae, notably the Dasyhelea.
GeniTalia .Apicolateral process of tergite 9 short, with five short bristles.Posterior margin of sternite 9 with triangular projection on each lateral side and a pair of horn-like projections.Gonostylus straight, basally broad, apically slender, proximal part covered by small setae, two long bristles at midpoint present (Figs 8-9).Parameres asymmetrical.Posterior process of parameres fused to right arm, tapering evenly along its length, evenly curved dorsad (Fig. 10).Aedeagus high arched, with apicolateral processes twisted along its length, tapering apically (Fig. 11).

Female
Unknown.

Remarks
Dasyhelea dominiakae sp.nov. is a member of the subgenus Dicryptoscena and is similar to D. notata and D. modesta.What distinguishes this species from those mentioned above, as well as other European species of Dicryptoscena, is the presence of triangular projections located on sternite 9.The male of D. dominiakae sp.nov.further differs from D. notata in having an evenly shaped posterior process and it is also separated from D. modesta by the equal length of the fourth and fifth palpal segments.

Diagnosis
The male genitalia of this species are characteristic in having the posterior margin of sternite 9 with a pair of processes apically separated by a shallow furrow.Gonostyli short, tapering to an indented sharp point.The aedeagus has broad apicolateral processes, and the posterior process of the paramere has fine hairs apically.

Etymology
Gothlandica refers to Gotland, a calcareous island located in the Baltic Sea east of mainland Sweden, where the holotype was collected.
GeniTalia .Apicolateral process of tergite 9 short.Posterior margin of sternite 9 apically divided into pair of obtuse projections.Gonostylus short, tapering to indented sharp point, covered by small setae, two long bristles at midpoint present .Parameres asymmetrical; posterior process fused with right arm; long and slender, distinctly bent apically, with fine apical hairs (Fig. 21).Aedeagus low arched with apicolateral processes broad, somewhat folded, extended laterally in distal part (Fig. 22).

Remarks
This species is a member of the subgenus Dicryptoscena, and the male is similar to that of Dasyhelea albidipes Santos Abreu, 1918 in the morphology of the genitalia, particularly by the presence of a pair of processes on the posterior margin of sternite 9. D. gothlandica sp.nov.differs from D. albidipes by the broadly shaped apicolateral processes and the short gonostyli.

Biology
The holotype was collected in a Malaise trap next to Lake Bästeträsk, with sourrounding vegetation consisting of Pinus sylvestris Linnaeus and small shrubs.One of the male paratypes was collected in a Malaise trap next to Lake Horsan, approximatley 5 km south-east of Bästeträsk.

Biology
The male was collected next to a pasture and the females from the vegetation in a marsh.

Discussion
The two new species belong to the subgenus Dicryptoscena and together with the new records the Swedish Dasyhelea fauna now contains 20 species, representing the five subgenera, i.e., Dasyhelea (6 spp.), Dicryptoscena (5 spp.), Prokempia (2 spp.), Pseudoculicoides (6 spp.) and Sebessia (1 sp.).The number of Dasyhelea species in neighboring countries ranges from 8 for Finland (Huldén & Huldén 2014), to 11 for both Norway and Germany (Stur & Borkent 2014;Szadziewski et al. 2012), 12 for Lithuania, and 30 in both Estonia and Poland (Szadziewski et al. 2012).According to Peterson & Achim (2001) there are 4 species likely to occur in Denmark based on distributional patterns, and Remm (1988), without locality data, lists Dasyhelea dampfi as having a distribution that includes Latvia.Comparing the species composition between neighbouring countries, there are now six species present in Sweden that have also been reported from either Norway or Finland.The species D. bensoni, D. bilineata and D. modesta are present in all three countries.Sweden shares 13 species with Estonia and Poland of which 8 are present in all three countries (Szadziewski et al. 2012).Dasyhelea flavoscutellata (Zetterstedt, 1850) has not been recorded from Sweden but is present in all the countries mentioned above except Lithuania, Denmark and Latvia, and is therefore likely to live in Sweden as well.Most of the new records for Sweden have been collected from the southern parts of the country and only two records are from a northern locality (Muddus National Park).The diversity from a major part of Sweden is thus poorly known and could probably yield many more species.The substantial increase of Dasyhelea species in Sweden probably signals that the knowledge of Dasyhelea in particular and Ceratopogonidae in general is poor.
Dominiak & Szadziewski (2010)is study by COI sequences differs from the original description in lacking long cerci and in having a subgenital plate with a lumen.According toDominiak & Szadziewski (2010)the type material is unavailable.