A new genus of anaxyelid wood wasps from the mid-Cretaceous and the phylogeny of Anaxyelidae (Hymenoptera)

Abstract

Two new species of wood wasps (Anaxyelidae), Orthosyntexis elegansgen. et sp. nov. and Orthosyntexis thantisp. nov., are described from mid-Cretaceous Kachin amber. Orthosyntexisgen. nov. exhibits characters and character combinations unique to the family, such as the combination of two mesotibial spurs, a length ratio of forewing 1Rs to 1M<1, a length to width ratio of forewing cell 1mcu ≥ 2, and the presence of 2M+Cu in the hind wing. The new species and morphological characters allow for an exploration of anaxyelid phylogeny. The phylogenetic results indicate that Anaxyelidae are monophyletic and it is suggested to classify the genera in two subfamilies, Syntexinae and Anaxyelinae, the latter including Kempendajinae and Dolichostigmatinae.

A new anaxyelid wood wasp (Hymenoptera: ‘Symphyta’) from the mid-Cretaceous Burmese amber

“…Following the key to the subfamily of Anaxyelidae proposed by Kopylov (2019: 342) our specimen keys out in the subfamily Syntexinae because of the couplets: forewing with pterostigma usually not reaching the midlength of cell 3r; cell 2r less than 3× as long as wide and usually significantly shorter than cell 1r; Rs+M present; forewing with Sc absent or present as a crossvein; forewing with cell 2r short and wide (less than 1.5× as long as wide), widened basally, or united with 1r (1r-rs completely or partly reduced); Rs+M usually longer than 2-M, sometimes bifurcating beyond 1m-cu. Gao et al (2021) also proposed the following characters, also present on the new specimen, to support an attribution to the Syntexinae: forewing with the maximum width of pterostigma not shorter than 2r-rs, 1r-rs absent and hind wing m-cu absent. Following the key to genera of Syntexinae proposed by Kopylov (2019: 346) the new specimen keys out close to Eosyntexis Rasnitsyn, 1990 because of the following couplets: forewing with 1r-rs completely lost; forewing with 2r-rs issuing from the middle of pterostigma; Rs+M much longer than 2-M, sometimes bifurcating beyond 1m-cu.…”

“…1). Recently, three anaxyelid species were described from Burmese amber, namely Sclerosyntexis hirsuta Wang et al 2020, Orthosyntexis elegans Gao et al Gao et al 2021(Wang et al, 2020Gao et al, 2021). All these species were placed in the Syntexinae and this placement was corroborated by the phylogeny of Gao et al (2021).…”

“…However, some wing venation characters preclude a confident placement within this genus (vide infra). Gao et al (2021) discussed the delineation of the four subfamilies of Anaxyelidae, as treated by Zhang & Rasnitsyn (2006) and Kopylov (2019) (viz., Anaxyelinae, Dolichostigmatinae, Kempendajinae, and Syntexinae), and provide a phylogenetic analysis of the family (Gao et al, 2021: fig. 8).…”

“…The figures were composed with Adobe Illustrator CC2019 and Photoshop CC2019 software. Wing venation nomenclature follows Gao et al (2021). The amber piece is housed in the Geological Department and Museum of the University of Rennes, France (IGR) under collection number IGR.BU-064.…”

“…To date, the fossil record of the Anaxyelidae encompasses 18 genera and 44 species (Gao et al, 2021). It is mainly com-posed of imprint or compression fossils (= rock fossils) while only four species are formally described from amber deposits: Eosyntexis parva Ortega-Blanco et al, 2008, Sclerosyntexis hirsuta Wang et al, 2020, Orthosyntexis elegans Gao et al, 2021, and Orthosyntexis thanti Gao et al, 2021(Ortega-Blanco et al, 2008Wang et al, 2020;Gao et al, 2021). Recently, a new species of 'Symphyta', namely Paraxiphydria resinata Gao et al, 2022, was described from the mid-Cretaceous Burmese amber and assigned to the family Xiphydriidae (Gao et al, 2022).…”