Lethrus (Mesolethrus) dyonini A. Shapovalov & Bagaturov, new species

(Figs. 7–8, 19–21, 30–31, 37–38, 40–41)

? Lethrus (Microlethrus) microbuccis: Semenov & Medvedev 1936: 81 (distribution: “environs of Tashkent up to foothills”).

Type locality. Uzbekistan, Tashkent Prov., S env. of Tashsay, 41°03’52.19”N 69°38’27.79”E, 838 m a.s.l.

Type material. Holotype, ♂ (ZIN), Uzbekistan, Tashkent Prov., 10 km SSW Krasnogorskyi, S env. of Tashsay, W footh. of Chatkal Mt. Range, 23.iii. 2014, 838 m a.s.l., 41°03’52.19”N 69°38’27.79”E S. Dyonin & I. Dyonina leg. Paratypes: allotype, ♀ (ZIN) and 5 ♂♂, 2 ♀♀ (ASPC, MBPC), same locality and collector as for holotype, but 18.–31.iii.2018; 5 ♂♂, 2 ♀ (ASPC, MBPC), same data as for holotype; 8 ♂♂, 6 ♀♀ (ASPC), Uzbekistan, Tashkent Prov., 14 km SSW Krasnogorskyi, S from Belovutsoy Riv., W footh. of Chatkal Mt. Range, 25.iii.2023, 794 m a.s.l., 41°01’43.38”N 69°38’27.71”E, S. Dyonin & I. Dyonina leg.

Diagnosis. Gena 2.5–3.1 times as large as eye width, laterally narrowly and obliquely truncate, anterolateral angle usu-ally more or less rounded, posterolateral angle obtuse (Figs. 7–8, 37). Punctation of pronotum relatively coarse, but not large, punctation of elytra double (sparse points and smaller dense points), elytra with only superficial thin trace of striae (Figs. 7–8). Dorsal surface of body with faint blue, green or bronze tinge or without distinct tinge (Figs. 7–8). Parameres comparatively wide and straight, but apically not widened, weakly curved inward (Figs. 19–21). Sclerotized apex of endophallus resembling a subrectangular plate (Figs. 30–31), in dorsal view anteriorly with pair of relatively short lobes (distinctly shorter than basal part of sclerite) and emargination between them.

Description of holotype (♂). Body length with mandibles 17.2 mm, body length to clypeal margin 15 mm, maximal width of body (elytra behind base) 9.8 mm.

Body (Fig. 7) rounded, convex; dorsal surface black, head and pronotum with faint bluish tinge, elytra with faint greenish tinge, venter with blue tinge; head and pronotum slightly shiny, elytra matt.

Head (Fig. 7). Labrum bilobed, right lobe weakly more developed than left one; anterior margin with row of long dark-brown setae. Clypeus transverse, trapezoidal with rounded anterior angles. Frontal impressions very fine, frontal tubercles indistinct. Frontoclypeal suture weakly visible only laterally; keels separating gena from frons not sharp, but more or less distinct. Gena exceeding eyes, noticeably projected laterally, in dorsal aspect 2.5 times as large as eye width, laterally narrowly and obliquely truncate, anterolateral angle rounded, posterolateral angle distinct. Postorbital denticles very small. Pleurostomal process short, hardly exceeding ventrolateral mandible outline, gradually narrowed from base to apex. Punctation double, relatively dense, coarse, partly merged and rugose, punctures less deep on clypeus; gena with fine rugose sculpture, punctures scattered and superficial.

Mandibles (Fig. 7) ventral processes lacking, ventral margin of left mandible weakly arcuate before middle, ventral margin of right mandible near straight; in dorsal aspect mandibles symmetrical, subapically slightly emarginate, dorsal mandible surface with only short low keels: longitudinal keel on left mandible in the distal third and transversal keel on right mandible distal of the middle.

Pronotum (Fig. 7) transverse, distinctly broader than base of elytra, maximum width behind middle; margins entirely bordered, not crenulate. Anterior angles weakly projecting anteriorly, rounded; posterior angles widely rounded. Punctation relatively coarse, punctures sparser on disc, denser and coarser on lateral sides; micropunctures poorly visible on disc, more distinct on lateral sides.

Abdomen. Subapical visible ventrite with tuft of long erect setae distally.

Elytra (Fig. 7) almost semicircular, apices of elytra truncate, epipleuron strongly narrowed apicad, epipleural keel not reaching elytral apex. Surface with superficial thin trace of striae; punctation smaller than on pronotum, superficial, double: sparse points and smaller dense points.

Legs (Fig. 7). Protibia with eight external teeth gradually diminishing proximad, and with row of tubercles on ventromedial edge.

Male genitalia (Figs. 19–21, 30–31). Aedeagus with oblong parameres: in ventral view parameres about half as long as phallobasis, parameres gradually narrowed, comparatively wide, straight along the interior margin, apices curved downwards and relatively weakly curved inward, in lateral view apically roundish. Sclerotized apex of endophallus resembles a subrectangular plate, in dorsal view anteriorly with a pair of relatively short lobes (distinctly shorter than basal part of sclerite) and emargination between them.

Variability of males. Body length with mandibles 15.1–17.4 mm, body length to clypeal margin 13.1–15.4 mm, maximal width of body (elytra behind base) 8.9–10 mm. Dorsal surface of the body as in holotype, or with faint bronze tinge or nearly black (in older and abraded specimens). Gena (Fig. 37) in dorsal aspect 2.5–3.15 times as large as eye width. Sometimes left mandible on ventral margin with small obtuse angulate protrusion near the middle (Fig. 38). Apices of elytra as in holotype (Fig. 40) or sometimes slightly prominent.

Females (Figs. 8, 41). Body length with mandibles in allotype 15.8 mm, body length to clypeal margin 14.1 mm, maximal width of body (elytra behind the base) 9.3 mm. Dorsal surface of the body in allotype with bronze tinge (Fig. 8). Variability in females: body length with mandibles 15.2–16.6 mm, body length to clypeal margin 13.4–14.6 mm, maximal width of body (elytra behind base) 8.9–9.5 mm. Apices of elytra angularly (Fig. 41) or roundish prominent. Tuft on subapical ventrite with relatively numerous setae (Fig. 41).

Distribution. The new species is known from two close localities about 30 km south-east of Tashkent near Tashsay and southwards of Belovutsoy River, in western foothills of Chatkal Mountain Range (see map, Fig. 44). Lethrus dyonini A. Shapovalov & Bagaturov, new species is distributed distantly from all other species of the subgenus Mesolethrus, and apparently vicariant with L. microbuccis in the north.

Etymology. The species is named in honour of Sergei Vladimirovich Dyonin (Tashkent, Uzbekistan), photographer, collector of insects and naturalist who has dedicated his life to the study of fauna and flora in Uzbekistan.

Ecology. Lethrus dyonini A. Shapovalov & Bagaturov, new species is found in foothills at an altitude of about 800 m a.s.l. in savannoid steppe (Fig. 48). Activity of imago is recorded in the second half of March. According to labels of studied material, the species occurs sympatrically with L. (Paralethrus) bituberculatus bituberculatus Ballion, 1871 .

Notes. The record of L. microbuccis for Tashkent (Semenov & Medvedev 1936) was not considered by Nikolajev (1987; 2003), but this data can be connected with Lethrus dyonini A. Shapovalov & Bagaturov, new species .