Opening Pandora's box of Pristocerinae: molecular and morphological phylogenies of Apenesia (Hymenoptera, Bethylidae) reveal several hidden genera

Abstract

The flat wasp Apenesia Westwood is one of the largest genera in Pristocerinae with 190 species worldwide. The lack of a single diagnostic morphological character has resulted in many distinct ground plans within Apenesia. Some authors have suggested Apenesia as polyphyletic. Here we aimed to investigate and delimit the genus based on morphological and molecular data. We analysed 163 morphological characters on tnt using ‘traditional search’, whereas Bayesian (BI) and maximum likelihood (ML) inferences were performed on 1553 concatenated nucleotide base pairs from COI and 28S sequences. Apenesia was recovered as polyphyletic in all analyses with up to 10 different lineages spread throughout the tree. We mapped female morphological characters onto the molecular tree to enlighten morphological evolution in the apterous females. Based on our morphological and molecular analyses, and on the taxonomic revision of holotypes and specimens, we propose six new genera in the Pristocerinae and revalidate the generic status of two: Acrenesia gen.n., Austranesia gen.n., Cleistepyris stat. rev., Dracunesia gen.n., Eleganesia gen.n., Epynesia gen.n., Pristonesia gen.n., and Propristocera stat. rev. We also propose four new generic synonymies: Neoapenesia syn.n. under Apenesia, Dipristocera syn.n. under Cleistepyris, Afrocera syn.n. and Neopristocera syn.n. under Propristocera. At the species level, we indicate Apenesia minor syn.n. under Propristocera tagala. In all, 162 new combinations, eight reinstated combinations and one new name to avoid homonymy are proposed. Apenesia is now defined as flat wasps having males with the mesoscutum gibbous, the genitalia with the paramere narrow and densely hairy, and the aedeagus with the ventral apical lobe elliptical and covered with lumps. Females of Apenesia can be distinguished from other Pristocerinae by having the head wider than the mesosoma, the antennae short, the mandible long, and the clypeus surpassing the toruli in the frons. This study reinforces the difficulties in defining Apenesia and other Pristocerinae genera. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:65FB3087-0F30-4851-B1BA-ED6E4518B958.

A new genus and species of Pristocerinae (Hymenoptera, Bethylidae) from upper Eocene Baltic amber with a review of conspecific association from insect fossils

“…nov. has the dorsal pronotal area with the lateral and anterior margins distinct and for this reason, this species does not belong to Apenesia Westwood, Afgoiogfa Argaman, Foenobethylus Kieffer and Parascleroderma Kieffer, because the males of these genera have the dorsal pronotal area with the lateral and anterior margins barely distinct. Additionally, the males of the last three genera, together with Austranesia Alencar & Azevedo (in Alencar et al 2018), have the prepectus very large, about 0.25× mesopectus length, whereas the male of this species has the prepectus reduced, about ~0.15× mesopectus length.…”

“…The male of this species has the ninth abdominal segment undivided and with the posterior margin weakly concave. For this reason, this species does not belong to †Eopristocera Falières & Nel, Pristocera Klug, Prosapenesia Kieffer, Propristocera Kieffer and Pristonesia Alencar & Azevedo (in Alencar et al 2018), because the males of Pristocera have the ninth abdominal segment divided into two lobes and the males of †Eopristocera, Prosapenesia, Propristocera and Pristonesia have the ninth abdominal segment with the posterior margin strongly concave.…”

“…eocena sp. nov. is projected forward, triangular, and the median clypeal carina is lower than frons, and for this reason, this species does not belong to Acrenesia Alencar & Azevedo (in Alencar et al 2018) Colombo & Azevedo (in Colombo et al 2020), because the males of Pristepyris have the median clypeal lobe short and truncate; the males of Eleganesia also have the median clypeal lobe short and with apical margin outcurved; males of Acrenesia and Dracunesia have the median clypeal lobe trapezoidal; males of Epynesia have the median clypeal lobe very projected and sharply angulated, and the male of †Uniceratops has the median clypeal carina higher than frons, horn-shaped.…”

“…With over 1,000 species in 26 genera, Pristocerinae are the most speciose subfamily within Bethylidae and are found worldwide (Azevedo et al 2018;Colombo et al 2020aColombo et al , 2021. The subfamily is known for its remarkable sexual dimorphism, with males possessing robust bodies, wings, and conspicuous eyes and ocelli while females are wingless, lack ocelli, and have eyes that are extremely reduced or missing (Alencar et al 2018). The vast majority of Pristocerinae species are known from 'males-only' or 'females-only' and conspecific associations between males and females are rare, typically the result of collecting specimens copulating or rearing them from the same host (Azevedo et al 2016;Alencar et al 2018;Chen and Azevedo 2020).…”

Integrated taxonomy unveils three new species of Foenobethylus (Hymenoptera, Bethylidae) from China

“…Genetic Kimura-2 parameter (K2P) distances of COI sequences within and between species were calculated in MEGA 7 with pairwise deletion for gaps (Kumar et al 2016). For phylogenetic analysis, sequences of specimens of three morphologically similar or phylogenetically close genera, Apenesia Westwood, Cleistepyris Kiefer, Dissomphalus Ashmead and Parascleroderma Kieffer, as suggested by previous studies (Alencar et al 2018; Chen and Azevedo 2020), were extracted from Alencar et al (2018) (Table 1). The 28S sequence of Foenobethylus emiliacasellae Várkonyi and Polaszek was downloaded from Genbank.…”