Diplotemnus balcanicus (Redikorzev, 1928) (Pseudoscorpiones, Atemnidae) rediscovered in Slovakia after 65 years

Diplotemnus balcanicus (Redikorzev, 1928) is reported for the second time from Slovakia. The species was first recorded from Slovakia in 1955 when two specimens were found in bat guano on the loft inside a church. After 65 years, one male was discovered inside a private family home 8 km from the 1955 record. The original 1955 material of D. balcanicus, from a private collection, has been revised. Additionally, a short description of the male of D. balcanicus and some identification notes on Eurasian diplotemnids are provided.


Introduction
The pseudoscorpion family Atemnidae contains 22 genera, of which 21 are Recent and one is from Eocene Baltic amber (Harvey 2013;Dunlop et al. 2020). Due to the poor definition of many genera which show only slight differences between them, Klausen (2005) called for more a transparent classification and revision of the family, which has not been carried out until recently.
Diplotemnus balcanicus was recorded for the first time from Slovakia under the name Diplotemnus piger (Simon, 1878); two specimens, a male and immature female, were found in the guano of mouse-eared bats, Myotis myotis (Borkhausen, 1797) and Myotis blythii (Tomes, 1857), in the loft of a church in the village of Chľaba in 1955 (Verner 1959). Herein, we report a new locality of D. balcanicus in Slovakia and also to provide morphological data on our specimen.

Methods
A single specimen of Diplotemnus balcanicus was found in a hallway inside a private family home in the village of Kamenica nad Hronom (Fig. 1). The house and the parcel borders on the Burdov National Nature Reserve and the area of the village used for gardening. The specimen was collected by hand during research which focused on the tracking of synanthropic arachnids. The specimen has been preserved in 75% ethanol. The specimen was immersed in lactic acid for clearing and studied on a temporary slide mount. After the study, it was rinsed in water and returned to 75% ethanol. Morphological and morphometric analyses were performed using a Leica DM1000 compound microscope with an ICC50 camera module (LAS EZ application, 1.8.0). Measurements were taken from digital images using the AxioVision 40LE application. Digital photographs (Fig. 2) were taken using a Canon EOS 5D Mark II camera attached to a Zeiss Axio Zoom V16 stereomicroscope. Image stacks were produced manually, combined using Zerene Stacker software, and edited in Adobe Photoshop CC.
The specimens collected from the village of Chľaba in 1955 were preserved as permanent slide mounts using Canada balsam. As the permanent slide mounts were in poor condition, they were melted in xylene, rinsed in water, and the specimens preserved in 75% ethanol.
The pseudoscorpion specimens were identified using the key by Christophoryová et al. (2011). Nomenclature and mensuration mostly follow Chamberlin (1931) and Harvey (2013), with the exception of the terminology of the rallum, pedipalpal and pedal segments (Harvey 1992;Judson 2007).
The new specimen is deposited in the zoological collection of the Natural History Museum in Vienna (NHMW). The specimens from 1955, in the collection of Dr Petr H. Verner (Verner 1959), is in the private collection of Dr František Šťáhlavský, which is currently deposited in the Department of Zoology, Faculty of Natural Sciences, Charles University, Prague, Czech Republic.

Discussion
Diplotemnus balcanicus was recently discovered in Hungary in owl pellets and bat guano in a church tower (Novák and Harvey 2015). In Slovakia, both findings were recorded from synanthropic habitats: first in the loft of a church (Verner 1959) and now inside a private family home. The new record is only 8 km from the locality of the 1955 record. Petrov (2004) reported D. balcanicus introduced in a house in Bulgaria. Some available information indicates that this species might be spread phoretically, which Beier (1963) has already suggested. Phoresy has been observed by Beier (1930), who found specimens attached to lepidopterans. Krajčovičová et al.
(2018) recorded D. balcanicus attached to the plumage of a dead specimen of Black-headed Gull, Chroicocephalus ridibundus (Linnaeus, 1766), in Russia. Dumitresco and Orghidan (1969) reported that D. balcanicus is often found in caves in Romania. There are also records of D. balcanicus from Afghanistan, Azerbaijan, Kyrgyzstan, Iran, and Turkmenistan, where it has been collected from leaf litter, under stones, and under tree bark (Beier 1959(Beier , 1971Schawaller and Dashdamirov 1988;Schawaller 1989). Schawaller (1989) also recorded it from Great Gerbil, Rhombomys opimus (Lichtenstein, 1823), nests in Turkmenistan. Older publications unfortunately make no mention of the habitats of D. balcanicus.
Our new record of D. balcanicus confirms its distribution in southern Slovakia. This species is currently known in continental Europe from Bulgaria, Hungary, Romania, Russia, and Slovakia (Redikorzev 1928;Dumitresco and Orghidan 1969;Petrov 1997Petrov , 2004Novák and Harvey 2015;Krajčovičová et al. 2018) and northwest as far as southern Slovakia, eastern to the Volga River delta, and south to southern Bulgaria (Fig. 1).