Fossil Record 23(1): 105-115, doi: 10.5194/fr-23-105-2020
Description of the male of fossil Calomicrus eocenicus Bukejs et Bezděk (Coleoptera: Chrysomelidae: Galerucinae) from Eocene Baltic amber using X-ray microtomography
expand article infoAndris Bukejs, Jan Bezděk§, Vitalii I. Alekseev|, Kristaps Kairišs, Ryan C. McKellar#
‡ Daugavpils University, Daugavpils, Latvia§ Department of Zoology, Mendel University, Zemědělská 1, 613 00 Brno, Czech Republic| Institute of Life Sciences, Immanuel Kant Baltic Federal University, Nevskogo street 14, Kaliningrad 236016, Russia¶ Institute of Life Sciences and Technologies, Daugavpils University, Vienības 13, Daugavpils, 5401, Latvia# Biology Department, University of Regina, Regina, SK, S4S 0A2, Canada
Open Access

A male representative of the extinct species Calomicrus eocenicus Bukejs etBezděk, 2014 (Chrysomelidae: Galerucinae) is found and described for thefirst time from Eocene Baltic amber using X-ray microtomography. Theaedeagus is well preserved within the body cavity of the specimen, and it isillustrated in detail. This fossil species exhibits distinct sexualdimorphism: the male has a smaller total body size, as well as acopula-adapted modification in abdominal ventrite 5 (apical margin deeplytrilobed, with round medial fovea present); meanwhile the female is largerin body size and has a simple abdominal ventrite 5 (without fovea,non-incised and widely rounded apically). Similar sexually dimorphiccharacters are typical for extant members of the tribe Luperini, and thisreport is the first time that they are described in an Eocene species. Theknown sexually dimorphic characters present in Coleoptera within EoceneBaltic amber are briefly discussed.