Two new species of Bergrothia Reitter, 1884, with a review of the Bergrothia fauna of Georgia (Coleoptera: Staphylinidae: Pselaphinae)

Two species of Bergrothia Reitter, 1884, a small Caucasian genus of Amauropini, are described and illustrated: B. svanetica spec. nov. (Georgia: Svaneti region) and B. simplex spec. nov. (Northeast Turkey: Ordu, Giresun). Including the new species, the genus now includes a total of nine species distributed in Georgia (six species), Northeast Turkey (three species), and Azerbaijan (one species). Based on abundant material collected during seven field trips conducted to Georgia between 2016 and 2021, the partly allo- and partly sympatric distributions of the Bergrothia species in Georgia are clarified and mapped. All of them are confined to the west of the country.

Numerous field trips conducted to Turkey and Georgia conducted by the authors, Heinrich Meybohm (Großhansdorf), and Michael Schülke (Berlin) in the past two decades yielded abundant material of Bergrothia, particularly from Georgia. Aside from previously described species, this material included also two unnamed species which are described in the present study. In addition, the fauna of Georgia is reviewed with a focus on the distributions of the species.

Material and methods
The material treated in this study is deposited in the following collections: MHNG Muséum d´Histoire Naturelle Genève (G. Cuccodoro) MNB Museum für Naturkunde, Berlin (coll. Schülke The morphological studies were conducted using Stemi SV 6 (Zeiss) and Discovery V12 (Zeiss) microscopes, and a Jenalab compound microscope (Carl Zeiss Jena). The images were created using digital cameras (Axiocam ERc 5s, Nikon Coolpix 995), as well as Labscope and Picolay software. The maps were created using Map Creator 2.0 (primap) software. Body length was measured from the anterior margin of the labrum to the apex of the abdomen. Other measurements are abbreviated as follows: HL -head length from the anterior margin of the frons to the posterior constriction of the head; HW -head width across and including eyes; AL -length of antennae; PpL -length of maxillary palpomere IV; PL -length of pronotum; EL -length of elytra along suture; EW -maximal width of both elytra combined. The "parameral" side (i.e., the side where the sperm duct enters) is referred to as the ventral, the opposite side as the dorsal aspect. Morphological terminology generally follows Chandler (2001). In samples collected by V. Brachat and H. Meybohm with larger numbers of specimens, the exact count was not always noted down. In such cases "> 5 exs. " is given in the material sections.

Etymology:
The specific epithet is an adjective derived from Svaneti, the Georgian region where this species is distributed.
Description: Habitus as in Fig. 1. Body length 2.35-2.50 mm. Body reddish-brown, glossy, with yellowish and depressed pubescence. Head weakly oblong (HL: 0.52-0.55 mm; HW: 0.45-0.48 mm), dorsally with coarse sculpture; vertex with two lateral keels not reaching posterior margin of head and with a median keel extending from posterior margin of head anteriad beyond foveae of vertex. Eyes reduced, composed of 1-5 often weakly pigmented ommatidia. Eye spine often indistinct or obsolete. Maxillary palpi short, slightly shorter than head (PpL: 0.45 mm). Antennae slender, slightly longer than combined length of head and pronotum (AL: 1.0-1.1 mm); antennomere I 1.3 times as long as broad; antennomere II narrower than I, approximately 1.5 times as long as broad; antennomeres III, IV, and VI slightly narrower than II and as long as broad or weakly oblong; antennomere V as broad as IV, weakly oblong; antennomere VII slightly longer than VI, as broad as long; antennomere VIII as broad as, and slightly shorter than VI; antennomeres IX-XI forming a club, IX as broad as long, X transverse, and XI approximately as long as the combined length of antennomeres VIII-X. Pronotum with scattered, fine, and partly rugose punctation, nearly as long as head (PL: 0.50 mm, PW: 0.48 mm); with two deep lateral, and one deep median ante-basal foveae; median fovea anteriorly extending into narrow sulcus; between median and lateral ante-basal foveae with a small spine anteriorly extending into a narrow carina reaching middle of pronotum. Elytra distinctly broader than long and 1.2 times as long as pronotum; with three distinct basal foveae and distinct sutural striae. Abdomen: tergite IV large, approximately as long as elytra, basally with a transverse and densely pubescent impression extending across two-fifths of tergal width; inner basal keels absent, outer keels directed obliquely postero-laterad; combined length of tergites V-VII shorter than tergite IV. Legs slender; inner side of metatibiae apically with slender fascicle of setae. : mesotrochanter with pronounced tooth; mesofemur occasionally with a minute tooth near base; inner side of mesotibia shallowly sinuate in apical third, with a small tooth at apical third and apically with a small spine; sternite VIII with shallow median impression; aedeagus (Figs 2-3) 0.38-0.41 mm long, asymmetric, with long and tapering apical portion.
Comparative notes: Regarding the structure of the aedeagus, B. svanetica is most similar to B. lederi (Saulcy, 1880), which differs from the new species by mesotrochanters with only a minute inner tooth, mesofemora with a distinct spine at basal third, by the presence of two teeth at the proximal end of the mesotibial excavations, and by an aedeagus of different shape both in dorsal and in lateral view. For comparison, new illustrations of the aedeagus of B. lederi are provided in Figs 7-8.

Distribution and natural history:
The distribution is confined to the Svaneti region, Georgia (Map 2), where the species is rather common. The specimens were collected by sifting leaf litter and dead wood and by soil-washing in moist and shady habitats at altitudes of 550-1250 m.

Etymology:
The specific epithet (Latin, adjective: simple) alludes to the weakly modified male meso-and metatibiae.
Head oblong (HL: 0.50-0.51 mm; HW: 0.42-0.43 mm), dorsally with scattered coarse punctation; vertex with two distinct lateral keels not reaching posterior margin of head, with a median keel extending to posterior margin of head, with a short keel between median and lateral keel on either side, and with a short keel above eyes. Eyes reduced, composed of 0-4 ommatidia mostly without pigmentation. Eye spine small or indistinct. Maxillary palpi short. Antennae slender, significantly longer than combined length of head and pronotum (AL: 1.05-1.15 mm); antennomeres I 1.5 times as long as broad, II narrower than I and weakly oblong, III, IV, and VI slightly shorter than II, slightly less than 1.5 times as long as broad, V of similar width, but nearly twice as long as broad, VII slightly broader than preceding antennomeres and nearly as long as V, VIII as broad as VII and approximately as long as broad, IX-XI forming a distinct club, IX and X weakly transverse, XI large, as long as combined length of VIII-X, and nearly twice as long as broad. Pronotum smooth, slightly shorter than head, and nearly as broad as long (PL: 0.45-0.46 mm; PB: 0.42-0.43 mm), with a lateral ante-basal fovea on either side and with a median ante-basal fovea; between median and lateral ante-basal foveae with a small tooth occasionally extending into a small carina; median ante-basal sulcus connected with posterior margin of pronotum by small keel; anterior portion of midline with a keel of variable length. Elytra 1.2 times as long as pronotum and 1.25 times as broad as long, each with three basal foveae and with distinct sutural striae. Abdomen: tergite IV large, slightly shorter than elytra, basally with a transverse and densely pubescent fovea extending across more than half of tergal width; inner basal keels absent, lateral keels directed obliquely posterolaterad; combined length of tergites V-VII shorter than tergite IV. Legs slender; inner side of metatibiae apically with slender fascicle of setae. : protibia shallowly sinuate at apical third; mesofemur with spine at basal fourth; mesotibia shallowly sinuate in apical third, with a distinct apical spine; sternite VIII with shallow median depression; aedeagus asymmetric, 0.44-0.46 mm long and shaped as in Figs 5-6.
The new species is distinguished from both of them particularly by the structure of the aedeagus and weakly modified male meso-and metatibiae. In B. saulcyi and B. solodovnikovi, the male mesotibiae have a pronounced median spine and the male metatibiae are excavate in the middle. Moreover, in B. solodovnikovi the elytra have only two basal foveae. For illustrations of B. saulcyi (as B. tibialis Hlaváč, 1999) and B. solodovnikovi see Hlaváč (1999Hlaváč ( , 2004.

Distribution and natural history:
The distribution is confined to two localities in Ordu and Giresun provinces, North Turkey. The specimens were sifted from leaf litter in a mixed forest with alder, spruce, bramble, and ivy, and in a forest with predominant beech and hazelnut at altitudes of 830 and 990 m.

The Bergrothia fauna of Georgia
Bergrothia is now represented in Georgia by six species, all of them distributed in the west of the country, eastwards to East Racha (close to the border with South Ossetia), the Rikoti pass, and the environs of Bakuriani in the Trialeti range. Four of the species, B. svanetica, B. mingrelica, B. lederi, B. adzharica) have allopatric distributions (Map 2), whereas the range of B. saulcyi, the most widespread species, overlaps with those of two other species (B. adzharica, B. lederi) and that of B. barbakadzei lies within the range of B. mingrelica (Maps 1-2). One of the species, B. barbakadzei, has exclusively been found in caves, while the others have been collected by sifting leaf litter and debris, as well as by soil-washing in various moist forest, bush, and shrub habitats at a wide range of altitudes (50-2290 m).
Bergrothia saulcyi (Reitter, 1877)  The original description is based on an unspecified number of syntypes collected in "den Wäldern des Suramgebirges" (Saulcy 1880). Subsequent records (Hlaváč 1999)  The original description is based on an unspecified number of syntypes from "Mingrelien, vom nördlichen Ingur" (Reitter 1884). The sole specimen in the Reitter collection, a syntype erroneously labeled as the holotype, was studied by C. Besuchet and P. Hlaváč (Hlaváč 1999 This recently described species is currently known from three caves in the Imereti region, Georgia (Maghradze et al. 2019). Its distribution is illustrated in Map 1.