On the new record of the sheet-web spider Erigonoplus foveatus comb . nov . from Slovakia , with comments on Erigonoplus simplex ( Araneae : Linyphiidae )

Mecynargus foveatus (Dahl, 1912) was recorded in the territory of Slovakia for the first time. Within two years of spider research, a single adult male was collected by beating branches of Scots pine (Pinus sylvestris) in the Borská nížina lowland. We also discovered that specimens of Erigonoplus simplex Millidge, 1979 from Bulgaria were misidentified as M. foveatus. Therefore, we suggest to consider E. simplex as a new record for Bulgaria and to exclude M. foveatus from the spider fauna of Bulgaria. A revised distribution of both species is presented and discussed. Based on the high similarity to Erigonoplus, M. foveatus is transferred to this genus as Erigonoplus foveatus (Dahl, 1912) comb. nov.

During a long-term research project on arboreal spiders from pines, a new species for Slovakia was found in the Borská nížina lowland.A single male identified as Mecynargus foveatus (Dahl, 1912) was collected by beating pine branches at the end of July 2014.Up to now only two species from this genus are known from Slovakia: M. longus (Kulczyński, 1882) and M. morulus (O. P.-Cambridge, 1873).Both are considered as rare and endangered species that occur in the alpine zone of the High Tatra Mts.(Gajdoš & Svatoň 1994, Svatoň & Kovalčík 2006).The original description of M. foveatus was based on females collected on the sunny meadow Herrscherberg (Brodowin) in Germany (Dahl 1912).The currently known distribution of M. foveatus is in Europe from France to Central European Russia (Nentwig et al. 2015).
During our detailed research, we also discovered that specimens of the similar species, Erigonoplus simplex Milidge, 1979, from Bulgaria were mistaken as M. foveatus.The former taxon is considered to be a Mediterranean species (Schröder et al. 2011), which has been reported only from Italy, France and Greece so far (Nentwig et al. 2015).The female of E. simplex has not been formally described, however it seems to have been collected by several arachnologists (e.g.Murphy & Murphy 1984, Russell-Smith 2014).Only one species of this genus, Erigonoplus spinifemuralis Dimitrov, 2003 has been as yet reported from Bulgaria (Blagoev et al. 2015).
In the present study we provide a short description of the morphology of M. foveatus and compare its distribution with that of E. simplex.Moreover, we suggest excluding M. foveatus from the spider fauna of Bulgaria and to include E. simplex as a new species for Bulgaria.We also propose the new combination Erigonoplus foveatus, comb.nov.

Material and methods
A managed Scots pine forest close to the Záhorie Protected Landscape Area was examined.About 100-year old pine trees with grassy undergrowth are located north of the village of Studienka (N48.540°,E17.141°, 216 m a.s.l.) near a meadow (Fig. 1).The study plot has been visited in approximately monthly intervals since 2013.Material was collected using the beating method and spiders were fixed in 70% ethanol directly in the field.Microphotographs were made using the EOS Utility software and a digital camera (Canon EOS 100D) connected to a stereomicroscope (Intraco Micro STM 823 5410).Photographs and figures were made by the second author, unless indicated otherwise.Identification of spiders was carried out according to the online key of Nentwig et

Results and discussion
Erigonoplus foveatus (Dahl, 1912) Dahl, 1912 For a complete list of references, see the World Spider Catalog (2015).
Material examined: A single male was collected by the first author on 26 th July 2014 by beating Scots pine near Studienka village (Western Slovakia).Unfortunately we cannot be sure about the geographic coordinates of the exact place of collection, because there are ten randomly numbered samples from this locality.

Comment on taxonomy, new combination
The taxonomic status of M. foveatus within the genus Mecynargus was previously discussed.This species has already been combined with several other genera, such as Savignia, Rhaebothorax and Eboria (Moritz 1973, World Spider Catalog 2015).Murphy & Murphy (1984) considered M. foveatus to be a synonym of Erigonoplus simplex.They discussed this problem with Dr. A. F. Millidge who, however, did not confirm the synonymy but agreed that M. foveatus it closely related to E. simplex and should be placed in the genus Erigonoplus.The male of M. foveatus has outstanding copulatory organs and hence cannot be mistaken for any other species of the genus Mecynargus, although it is closely related to the genus Erigonoplus (with its type species E. inclarus (Simon, 1881), see Millidge 1975) and we herewith transfer it to this genus as Erigonoplus foveatus (Dahl, 1912), comb.nov.

Diagnosis
Erigonoplus foveatus can be confused with the rare Mediterranean species Erigonoplus simplex Millidge, 1979.Unlike E. foveatus, E. simplex lacks the elevated head region (Fig. 4), and can be distinguished by its larger body size.Males of E. simplex are ca 2.45 mm long in comparison to E. foveatus which is 1.9-2.0mm long (Nentwig et al. 2015).Male palps of both species are very similar.

Description of the Slovakian Erigonoplus foveatus sample
Male (Fig. 2): Total length 1.84 mm, carapace length 0.77 mm and width 0.6 mm.Dark brown shiny carapace with elevated head and shallow medial groove; chelicerae on outer side with distinct stridulatory organ; dark brown shiny sternum; legs yellow, coxa 4 with small conical spur.Abdomen dark grey, without pattern, book lung opercula with highly developed stridulatory areas.
Male palp (Fig. 3): Pedipalp tibia with complex apophysis consists of larger concave rounded one with small pointed spur.Protegulum with a small process; radical tailpiece spiral; embolic membrane present; embolus barely visible.

Biological and ecological notes
Erigonoplus foveatus is considered to be a xerophilous photobiont species (Thaler 1969, Rozwałka et al. 2014).Although, E. foveatus was recorded from peat bogs in Finland and Karelia (NW Russia), it seems to prefer sunny and grassy biotopes in highlands and lowlands (see Tab. 1).This spider was also collected on agrocenoses such as orchards (Rozwałka et al. 2014), pastures (Ratschker & Roth 2000, Evtushenko et al. 2012) and fields (Eskov 1988, Lukashevich pers. comm.).Interestingly some of the records were associated with Scots pine, similar to the present record from Slovakia (see Tab. 1).Although we consider our finding in such a habitat acciden-tal, E. foveatus may be a constant species of the Slovak spider fauna as it is known from neighbouring countries (Fig. 5).With regard to previous records, E. foveatus may be found in the nearby meadows or on other grassy localities.
This species builds webs usually among the base of grass tussocks (Buchar & Růžička 2002, Ledoux et al. 2003) and in depressions on the bare or sparsely-vegetated ground (Lissner pers. comm.).Adults occur from May to August, with the most active period around June and July (e.g.Thaler 1969, Moritz 1973, Vilbaste 1987, Hänggi 1993, Gnelitsa 2011).Females were also collected in the winter period (Hänggi 1993).

Distribution
Erigonoplus foveatus is a rare species occurring in Europe from southern France (Pyrenees) to Russia (Karelia, Ural and Caucasus) (Fig. 5, Tab. 1).In cooperation with Dr. Christo Deltshev we revised the Bulgarian material published by Lazarov (2005) and Erigonoplus simplex was misidentified as E. foveatus.Consequently, we argue that E. simplex should be treated as a new record for Bulgaria and that E. foveatus has not yet been recorded there.Our thanks go to Robert Bosmans for his help in confirming the species identification and also to Stano Pekár who allowed us to examine specimens during the European arachnology congress in Brno.We are grateful to Christo Deltshev and Sylvian Lecigne for their helpful discussion and photos for checking identifications.Special thanks go to Inese Cera, Valery A. Gnelitsa, Christo Deltshev, Seppo Koponen, Jørgen Lissner, Gordana Grbić and Ivan G. Lukashevich for literature and detailed information about existing records.And our thanks go also to Peter Vďačný and anonymous reviewers.The study was supported by VEGA 1/0066/13, 2/0035/13 and MK-TA/2015/2.2.

Fig. 1 :
Fig. 1: The 100 year-old Scots pine forest at the study plot, near the village of Studienka (SW Slovakia), where Erigonoplus foveatus was collected (photo by M. Kulfan)