A new wasp genus of Cirrosphecidae (Hymenoptera: Apoidea) from mid-Cretaceous amber of northern Myanmar

Abstract

A new apoid genus with one new species Heterosphex wuni Li, Rosa, Melo and Shih gen. et sp. nov. is described in Cirrosphecidae based on a male wasp from mid-Cretaceous Myanmar (Burmese) amber. The new taxon is placed in Cirrosphecidae due to its swollen, ring-like metanotum with anterior margin surrounding the scutellum; omaular sulcus and omaular carina absent; propodeum short, with rounded edges and distinctly slanted; metapostnotum extending as a narrow triangle onto posterior surface of propodeum; notaulus not indicated; claws with subapical teeth; and mid tibia with one spur. A key for genera and species of Cirrosphecidae is provided. Up to date, all taxa in Cirrosphecidae are known only from mid-Cretaceous Myanmar amber.

Introduction

Cirrosphecidae, a family of apoid wasps known only from mid-Cretaceous Myanmar (Burmese) amber, had its status raised to family by Rosa and Melo (2021). Originally, this taxon was described by Antropov (2000) as a subfamily of Sphecidae, based on only one Myanmar amber species Cirrosphex admirabilis Antropov, 2000. Now, it includes two subfamilies: Cirrosphecinae Antropov, 2000, with two genera Cirrosphex Antropov, 2000 and Haptodioctes Rosa and Melo, 2021; and Glenocephalinae Rosa and Melo, 2021 with one genus Glenocephalus Rosa and Melo, 2021 (Antropov, 2000; Rosa and Melo, 2021).

Members of Cirrosphecidae look like ordinary crabronid wasps, but as shown by Rosa and Melo (2021), a series of morphological characters support their close relationship with bees, including mid tibia with one spur and possession of a basitibial plate in the hind tibia of female Cirrosphecinae. With removal of Melittosphecidae from Apoidea (see Rosa and Melo, 2021), Cirrosphecidae constitutes the closest known relatives of bees among the apoid wasps.

The Myanmar amber biota, comprising 8 classes, 66 orders, 596 families, 1357 genera and 2059 species of arthropods (Ross, 2021), is the most diverse and well-preserved in the Mesozoic. In recent years, many well-preserved hymenopteran fossils have been reported from Myanmar amber, e.g., Evanioidea (Li et al., 2015, 2018b; Shih et al., 2019), Pelecinidae (Guo et al., 2016), Ichneumonidae (Li et al., 2017a, 2019b), Stephanoidea (Li et al., 2017b; Jouault et al., 2021), Braconidae (Chen et al., 2021; Li et al., 2021), Myanmarinidae (Zhang et al., 2018; Li et al., 2018a), Panguidae (Li et al., 2019a), Embolemidae (Perkovsky et al., 2020), Bethylidae (Jouault et al., 2021), as well as the apoid families Allommationidae, Cirrosphecidae, Crabronidae and Spheciellidae (Rosa and Melo, 2021). Herein, we describe a new amber wasp: Heterosphex wuni Li, Rosa, Melo and Shih gen. et sp. nov. in Cirrosphecidae based on one well-preserved Myanmar amber specimen. The new taxon can be accommodated within the classification proposed recently by Rosa and Melo (2021), with few adjustments, and represent an important addition to the knowledge of the subfamily Cirrosphecinae.