New extinct ant genus (Hymenoptera, Formicidae, Myrmicinae) from late Eocene Rovno amber Author Radchenko, Alexander G. I. I. Schmalhausen Institute of zoology of National Academy of Sciences of Ukraine, Kiev, 01030, Ukraine agradchenko@hotmail.com Author Proshchalykin, Maxim Yu. https://orcid.org/0000-0001-7870-8226 Federal Scientific Center of the East Asia Terrestrial Biodiversity, Far East Branch of the Russian Academy of Sciences, Vladivostok 690022, Russia text Journal of Hymenoptera Research 2021 2021-08-24 84 271 282 http://dx.doi.org/10.3897/jhr.84.65238 journal article http://dx.doi.org/10.3897/jhr.84.65238 1314-2607-84-271 0789CE6257A54E5EB2EE31B936A673DC 45E27C8FC2575941ACD6231216D3DD49 5349369 Lelejus venustus sp. nov. Figures 1 , 2 , 3 , 4 Material examined. Holotype : male, SIZK No. UA-27845, Ukraine , Rovno Region , Klesov , Rovno amber, late Eocene , 33.9-37.8 Ma ; AntWebCASENT0917546. Diagnosis. As for the genus. Description. Male. Body length 4.1 mm. Head subglobular, slightly wider than long, gradually rounded behind eyes, without marked occipital corners and with convex occipital margin. Eyes very large, their maximum diameter half of head length, situated distinctly in front of mid-length of sides of head, so genae very short. Ocelli large, forming obtuse triangle, diameter of central ocellus subequal to width of scape. Frons relatively narrow, 0.25 head width, frontal sockets fully exposed. Frontal triangle well marked. Mandibles quite long, ca. 0.4 head length. Apical segment of maxillary palps twice as long as preapical one. Antennal scape ca. twice as long as width and ca. 4.5 times shorter than head. First funicular segment very short, somewhat shorter than wide and half as long as second segment; all subsequent segments of same width; second to 11th segment subequal in length, last segment twice as long as second one. Whole head with coarse reticulation, clypeus with sinuous longitudinal rugae, its central part and mandibles smooth; eyes surrounded by narrow foveate groove. Temples and occipital margin with quite numerous subdecumbent hairs of moderate length; antennal scape with sparse subdecumbent, but quite long hairs; funicular segments with very short and abundant decumbent to subdecumbent pilosity; anterior clypeal margin without long setae, with only a few short, thin hairs; mandibles with quite long semierect hairs. Figure 1. Lelejus venustus gen. et sp. nov., holotype, male (AntWebCASENT0917546) A head, dorsal view B head and antennae, dorsal view C, D body, right lateral view ( C ); left dorso-lateral view ( D ). Scale bars: 0.1 mm ( A ); 0.5 mm ( B-D ). Mesosoma 1.6 times as long as high, scutum moderately convex, posterior surface of propodeum 1.2 times as long as dorsal one. Notauli deep and wide, distinctively arched in profile view, with coarse short transverse rugae (foveate). Petiole with distinct peduncle, 1.6 times as long as high, its node with widely rounded dorsum; postpetiole subglobular, slightly higher than petiole. Spurs on meso- and metatibiae relatively long, equal to width of tibia at point of their articulation. Scutum, scutellum and propodeal dorsum with coarse reticulation; sides of pronotum, mesopleura and lower part of sides of propodeum smooth; gaster smooth. Figure 2. Lelejus venustus gen. et sp. nov., holotype, male A head, lateral view B mandibles C petiole and postpetiole, lateral view. Scale bars: 0.25 mm ( A ); 0.1 mm ( B, C ). Mesosoma, waist and gaster with moderately dense erect to semierect hairs, legs with decumbent to subdecumbent pilosity, femora with additional longer suberect hairs. Genitalia small and barely visible. Forewings: pterostigma rather long and narrow; cross-vein rs-m completely reduced, so that cell rm absent; cell mcu of moderate size, trapezoidal, its height subequal to midline, its distal point does not reach level of basal end of pterostigma, vein section 1RS+M somewhat shorter than 1Cu; cell 1+2r heptagonal, relatively short, veins 1R1, 2R1 and 3R1 of nearly equal length; vein sections 2RS+M and 3RS subequal in length; cross-veins 2r-rs and 1RS well developed, 1RS slightly inclined toward base of wing, 2r-rs almost perpendicular to 2R1 and 3R1 at the point of their junction. Figure 3. Lelejus venustus gen. et sp. nov., holotype, male, mesosoma, lateral view. Scale bar: 0.5 mm. Measurements (in mm). HL 0.73, HW 0.77, FW 0.19, SL 0.16, OL 0.36, GL 0.06, MdL 0.30, ML 1.43, MH 0.88, PL 0.39, PH 0.27, PPL 0.27, PPH 0.29, HTL 0.60, WL 3.18, WW 1.13; length of funicular segments from second to 11th: 0.13, 0.13, 0.14, 0.14, 0.14, 0.14, 0.14, 0.14, 0.16, 0.26. Indices : CI 0.95, SI1 0.22, SI2 0.21, FI 0.25, MdI 0.41, OI1 0.50, OI2 0.47, PI1 0.54, PI2 1.58, PPI1 0.39, PPI2 0.95, MI 1.62, WI 2.83. Workers and queens. Unknown. Etymology. From Latin venustus - pretty, nice, fine, which means that the described specimen has a fine general appearance. Figure 4. Lelejus venustus gen. et sp. nov., holotype, male A forewing B hind wing. Scale bar: 0.5 mm.