A new genus and species of polypore fungus beetle in Upper Cretaceous Burmese amber (Coleoptera, Tetratomidae, Eustrophinae)

A new polypore fungus beetle is described and figured from an individual preserved in Upper Cretaceous (Cenomanian, ca. 99 Ma) amber from northern Myanmar. Cretosynstrophus archaicus gen. et sp. nov. is confidently placed in the extant subfamily Eustrophinae based on its elongate oval body and pronotum with two basal, sublinear impressions. It shares several characters belonging to two Recent tribes (Eustrophini and Holostrophini), but it cannot be attributed to either of them. Together with other tetratomid genera from the Cretaceous, the new discovery implies that the Recent small family Tetratomidae is much more diverse and more widespread than previously documented. In addition, a morphological similarity between Cretosynstrophus and extant Synstrophus suggests a similar fungi feeding habit for Cretosynstrophus, highlighting an ancient association between tetratomid beetles and fungi in the Mesozoic.