A basal chalcidoid (Insecta : Hymenoptera) from the earliest Cretaceous or latest Jurassic of Mongolia

Abstract

Khutelchalcis gobiensis gen. et sp. n. (Khutelchalcididae fam. n.), based on a tiny impression fossil collected from the lowermost Cretaceous or uppermost Jurassic deposits of Khutel-Khara in East Mongolia, was studied using an environmental chamber scanning electron microscope. Character analysis suggests that the fossil belongs to a putative basal group of the Chalcidoidea. The greatly reduced wing venation, apparent presence of multiporous plate sensillae with long aperture on the flagellomeres, and a high antennal insertion all suggest that the new taxa is related to the Chalcidoidea. The angulation of fore wing vein Cu at the M+Cu fork is similar to that of Jurassic Jurapriidae, Cretaceous Serphitidae as well as various chalcidoids. This character might be a synapomorphy for Chalcidoidea + Serphitoidea (including Mymarommatidae) + Jurapriidae, which in turn are possibly a sister clade to Platygastroidea. The small size of this species is discussed in relation to conflicting scenarios concerning the plesiomorphic biology of the chalcidoid+proctotrupoid linage. Mymarommatidae and Serphitidae are combined in a single superfamily, Serphitoidea Brues, 1937 (= My-marommatoidea Debauche, 1948, syn. nov.).