Duvalius (Duvalius) gregoi Maghradze, Lohaj & Faille 2025, sp. nov.

Duvalius (Duvalius s.str.) gregoi Maghradze, Lohaj & Faille sp. nov. (Figs 17–21) Type material. Holotype male, labelled: “ GEORGIA, Racha-Lechkhumi and Kvemo Svaneti region, Racha karst massif, Kvedi II Cave, dark zone, 24.v.2023, E. Maghradze leg.” (IZISU). Paratypes: (4♂♂, 4♀♀): 2♂♂, 2♀♀: same data as holotype, but 07.xii.2023 (IZISU); 1♂, 1♀: same data as holotype, but 07.xii.2023, (SMNS); 1♀: same data as holotype, but 12.ix.2022, J. Grego leg., with extraction code RL-88 (CRL). Stored in ethanol: 1♂ - EM119 (07.xii.2023, E. Maghradze leg. (IZISU)). Diagnosis. Medium sized Trechine beetle, with the character states of the genus Duvalius subgen. Duvalius Delarouzée, 1859 (sensu Jeannel, 1928). Body elongated, depigmented, reddish-brown, glabrous, with strongly reduced eyes Microsculpture on head, submentum with 6 or 7 setae, pronotum and elytra well distinct, composed of transverse meshes. Trapezoid pronotum, almost as wide as long. Elongate, ovoid elytra with well developed striae; indistinct, widely rounded humeri. Male protarsi with the first two tarsomeres dilated and toothed at their internal magrins. Habitus as in Figs 17–19. Description. BL: 4.97–5.8 mm. Head (Figs 17–19): glabrous, longer than wide, distinctly longer and narrower than pronotum, HL 1.05–1.2 mm, HW 0.85–0.99 mm, Index HL/HW 1.15–1.32. Temples convex, neck constriction distinct. Frontal furrows deep, complete, reaching neck constriction. Head with two pairs of anterior supraocular setae and two pairs of long supraorbital setae, anterior pair behind middle of head length, posterior pair at hind part of head near the neck. Mandibles relatively long and slender, acutely pointed, the right one with tridentate basal teeth. Eyes flattened, strongly reduced, with only few ommatidia (Fig. 19). Clypeus quadrisetose; labrum concave, with six setae near the anterior margin, extreme ones being the longest and anterior lateral margins with 4 to 6 short setae. Mentum bisetose, with a bifid, protruding tooth; labial suture complete, mentum and submentum not fused; the latter with 6 or 7 setae; maxillary palpi short, glabrous; labial palpi glabrous except penultimate palpomere, which is quadrisetose. Antennae elongate, filiform, stretching backward reaching middle of elytra; pubescent from antennomere ii, scape bearing a few setae; AL 3.26–3.76 m.; length of antennomeres (from scape to terminal segment, in mm): 1.00 / 0.89 / 1.36 / 1.29 / 1.29 / 1.25 / 1.10 / 1.03 / 1.00 / 0.96 / 1.21. Pronotum: Trapezoid, almost as wide as long, PL 0.87–1.05 mm, PW 1.08–1.21 mm. Index PL/PW 0.81–0.96; with maximum width in anterior fifth. Lateral sides slightly rounded and strongly sinuate before posterior angles, which are distinct and protruding; anterior angles rounded, obtuse. Lateral furrows well developed, deep, with two pairs of setae; anterolateral setae situated in the anterior fifth, basolateral pair before hind angles. Basal impressions deep, not punctuated; median furrow weakly marked, visible in middle of pronotum (Figs 17–18). Elytra: ovoid, elongate, EL 2.84–3.19 mm, EW 2.11– 1.83 mm, Index EL/EW 1.55–1.58; with maximum width before the middle of elytral length. Humeri indistinct, widely rounded, scutellum small, flat; single pair of parascutellar seta present; scutellar striola absent. Elytral disc convex, elytral striae well-developed, distinctly punctate. Elytra with two pairs of long and thick discal and one similar preapical setiferous pore, preapical pair located near elytral base in stria 3 and 4, discal pores situated in the anterior half of elytral length of stria 3 and second pairs of stria 2 and 4 (Figs 17–18). Legs: relatively short; protibiae with sulcus on dorsal side, antennal cleaning organ well developed. First two tarsomeres of male protarsi distinctly dilated and toothed at their internal margins. Tarsal claws long and slender, pointed at apex. Abdominal ventrites: Glabrous, with a pair of short paramedian setae; last ventrite with one seta each side in males, two seta each side in females. Male genitalia: Median lobe of aedeagus very narrow, elongated, and gently curved in lateral view; slightly wider at basal bulb, subparallel, almost straight in dorsal view. Apex elongate, shortly curved upward. Internal sac of aedeagus (endophallus) poorly sclerotized. Parameres slender, each with four long, straight apical setae (Figs 20–21). Female genitalia: gonocoxite II, distinctly sclerotized, unguiform, slightly longer than wide, with 3–4 ensiform spine on the dorsal and lateral surfaceand apical groove that harbours two small nematiform setae; Gonocoxites I simple, triangular, weakly sclerotized, with 4–5 long setae on the inner margin, near the corner and 3–5 setae on the distal margin; laterotergite less sclerotized with 12–15 setae near the inner margin and 6–7 in the basal half on the disc (Fig. 13). Differential diagnosis: Duvalius gregoi sp. nov. is the fourteenth species of the genus described from the Caucasian region. All Caucasian Duvalius species belong to the subgenus Duvalius s. str. and exhibit significant variation in morphological traits, reflecting various stages of adaptation to the subterranean environment. In general, the body is more or less flattened and varies in the following morphological characteristics: • colour ranges from piceous/reddish-brown to pale testaceous; • eyes from strongly reduced, flat with almost no ommatidia to slightly reduced, prominent eyes; • legs and antennae from thin and long to thicker and shorter. To date, five Duvalius species have been recorded from Georgia: D. abyssimus Reboleira & Ortuño, 2014, D. iljukhini (Dolzhanski & Ljovuschkin, 1985), D. kurnakovi Jeannel 1960, D. megrel Belousov, 1991 and D. sokolovi Ljovuschkin, 1963 (Belousov, 1991; Belousov & Zamatajlov 1995; Barjadze et al. 2019; Reboleira & Ortuño, 2014). Duvalius gregoi sp. nov. appears to be most closely related to D. sokolovi Ljovuschkin, 1963 from the Abkhazeti region, Trechus’ Cave. Both species share similar reddish-brown body coloration but can be easily distinguished by the following combination of characters: a) Body size: the new species is smaller, with a body length of 4.97–5.8 mm, while D. sokolovi measures 6.0– 6.2 mm in length. b) Pronotum: trapezoid and slightly wider than long in the new species, whereas in D. sokolovi, the pronotum is longer than wide. Etymology. Patronymic, dedicated to our dear friend Jozef Grego (Horná Mičiná, Slovakia) enthusiastic speleologist and biospeleologist, specialist on subterranean snails and discoverer of this new species. Distribution: The species is known only from the type locality, Kvedi II Cave, located in the Racha karst massif, Racha-Lechkhumi and Kvemo Svaneti regions, Western Georgia (Map 1). The caves in this area are biologically underexplored, and D. gregoi sp. n. may be found in adjacent localities. Ecology: The species is troglomorphic and was found in a small crack at the end of the cave. The fauna of Kvedi II Cave is poorly studied; so far, only one species of snail, Mucronaria kartvelica Mumladze, Grego & Szekeres, 2023, has been recorded from this cave (Mumladze et al. 2023). All Duvalius species known so far from the Caucasus can be identified using the following key: