A new fossil Eurypinae genus and sexual dimorphism in the representatives of Omineus (Coleoptera: Mycteridae) from Tertiary amber of Europe Author Alekseev, Vitalii Igorevich 0000-0003-4390-5443 Shirshov Institute of Oceanology, Russian Academy of Sciences, Nahimovskiy prospekt 36, 117997 Moscow, Russia. alekseew 0802 @ yahoo. com; https: // orcid. org / 0000 - 0003 - 4390 - 5443 & Kaliningrad Regional Amber Museum, Marshal Vasilevskii square 1, Kaliningrad 236016, Russia. alekseew0802@yahoo.com Author Bukejs, Andris Institute of Life Sciences and Technologies, Daugavpils University, Vienîbas 13, Daugavpils LV- 5401, Latvia. Author Pollock, Darren Andrew Department of Biology, Eastern New Mexico University, Portales, NM 88130 USA. text Zootaxa 2020 2020-07-29 4820 3 551 562 journal article 8966 10.11646/zootaxa.4820.3.8 f702f2bf-e817-4863-96f7-f20015f61de3 1175-5326 4398204 B8AAC629-F431-49E2-B15C-80CCC0CE070C Omineus febribilis Alekseev, Pollock & Bukejs, 2019 Material examined. One specimen with collection number 4438-27 [ KRAM ]; Baltic amber, adult, female (ab-dominal ventrite 2 without sex patch), complete specimen. The beetle inclusion is preserved in a medium-sized polished piece of transparent amber with dimensions of 35×13× 9 mm without supplementary fixation. Syninclusions are represented by numerous fagacean stellate trichomes. Body length of the specimen is 3.5 mm (the holotype is 3.1 mm long), but other main characters of the specimen fully correspond to that of Omineus febribilis Alekseev, Pollock & Bukejs, 2019 and the specimen is attributed to this species . One specimen with collection number AWI-059 [ CVIA ] ( Figs. 6–8 ); Baltic amber, adult, male (abdominal ven-trite 2 with sex patch), complete specimen. The beetle inclusion is preserved in an elongate-oval, polished piece of transparent amber with dimensions of 25×13× 6 mm without supplementary fixation. Syninclusions are represented by a few stellate trichomes of plant origin, minute gas vesicles, and one Acari specimen. Body length of the specimen is 2.8 mm . FIGURES 6–8. Omineus febribilis , AWI-059 [CVIA], male, habitus, X-ray micro-CT rendering: 6—dorsal view; 7—ventral view; 8—lateral view. Scale bars represent 1.0 mm. One specimen with collection number JD 8369 [ JDC ] ( Figs. 9–14 ); Baltic amber, adult, male (abdominal ven-trite 2 with sex patch), complete specimen. The beetle inclusion is preserved in an elongate, polished piece of transparent amber with dimensions of 15×9× 8 mm without supplementary fixation. Syninclusions include a few stellate trichomes of plant origin. Body length of the specimen is 2.9 mm . Note. Specimen No. AWI-059 [ CVIA ] was reported in Alekseev et al. (2019) and identified as belonging to Eurypinae without further generic attribution. The X-ray micro-CT scans provide sufficient data, which led us to consider the specimen to be a male of Omineus . The absence of clear differences in external morphology between this male specimen and the holotype (female), as well as the similarities in structural detail to specimen JD 8369, also identified as a male of the Omineus , led us to conclude that all specimens represent a single fossil species from Baltic amber, Omineus febribilis . The availability of two additional males and one female allow us to provide the sexually dimorphic characters for diagnosis of the fossil O. febribilis , originally described on the basis of the female specimen only. The size variability of the extinct species (2.8–3.5) is established based on the presented material: apparently, the males are shorter ( 2.8–2.9 mm ), the females are longer ( 3.1–3.5 mm ). The eyes of the male are slightly larger and more protruding, and the frons is narrower in the male, compared to the female. Abdominal ventrite 2 of the male has a prominent sex patch, mesally gibbose but not clearly delimited, without especially dense setae, almost as long as the mesal length of ventrite 2. The apical margin of the male pygidium is weakly and widely emarginate medially.