A cretaceous fly trap? remarkable abdominal modification in a fossil wasp

Phylogenetic position of †Sirenobethylus gen. nov. We describe a new genus †Sirenobethylus, from mid-Cretaceous Kachin amber, based on sixteen specimens. The new genus is readily attributed to the Aculeata by its concealed posterior abdominal segments and ovipositor apparatus [28]. †Sirenobethylus has 9 flagellomeres and forewing with 8 closed cells, which is different from Vespoidea sensu lato [29] and Apoidea (antenna with 10 flagellomeres in female and forewing usually has 10 or 9 closed cells) [30, 31]. Therefore, †Sirenobethylus probably belongs to Chrysidoidea. We retrieve this superfamily as monophyletic (Fig. 4, Additional file 1: Dataset S2) [32], unlike some recent molecular studies [33]. All †Sirenobethylus specimens examined are macropterous females; given the unique diagnostic traits in, e.g., wing venation, and the somewhat isolated phylogenetic position of the new taxon (Fig. 4), it is not possible to associate these females with any males known from Kachin amber. They ... Read full article.