Abstract
The Cretaceous fossil record of the aculeate superfamily Chrysidoidea has been greatly enriched in the past few years, thanks especially to the abundance of available material in the late Albian-early Cenomanian amber from the Kachin state (Myanmar). We here document the discovery of a new genus and species, Thagyaminobythus martini gen. et sp. nov., from Kachin amber, emphasizing the extraordinary diversity of chrysidoid wasps in this deposit. The genus is left as incertae sedis within the superfamily because it exhibits a combination of Scolebythidae, Bethylidae and Chrysididae features. We discuss the possibility that Thagyaminobythus martini gen. et sp. nov. could retract its posterior metasomal segments and the co-occurrence of such a structure in several chrysidoid families.