Kryzhanovskiana olegi gen. et sp. nov., a remarkable eyeless representative of the tribe Metriini (Coleoptera: Carabidae: Paussinae) from Upper Cretaceous amber of northern Myanmar

Abstract

Kryzhanovskiana olegi gen. et sp. nov. is described from Cenomanian Burmese amber within the tribe Metriini (Paussinae). By having some peculiarities in the body shape and structure of the head (elongate mandibles, reduced eyes, additional setigerous pores on frons and vertex), the new genus is rather distinct from the two modern genera Metrius Eschscholtz, 1829 and Sinometrius Wrase et Schmidt, 2006, each with restricted distribution in western North America (Metrius) and in East Asia (Sinometrius). Like the modern members of Metriini, the new genus could inhabit forests and keep a predaceous mode of life. A compact body with legs not adapted to digging and reduced eyes in Kryzhanovskiana olegi gen. et sp. nov. seem to indicate on inhabitance in dark enclosed interspaces, such as thick layers of dead wood or hollows in rotten tree trunks. The discovery of a new remarkable representative of the tribe Metriini in Cretaceous Burmese amber confirms the previous suggestions that Metriini represent an old relict group of Carabidae which was more diverse and more widely distributed in the past. Hypotheses on evolution of the tribe Metriini are discussed.