Arcanys Chemyreva, 2024

Chemyreva, Vasilisa G., Legalov, Andrei A. & Perkovsky, Evgeny E., 2024, A new genus of Ambositrinae (Hymenoptera, Diapriidae) from Rovno amber and remarks on the Eocene distribution of the subfamily, Ecologica Montenegrina 79, pp. 104-112 : 105-107

Genus Arcanys Chemyreva , gen. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:8064C8A1-53D1-45A7-B176-4785DD0DF9FB

Type species. Arcanys rostratus Chemyreva , sp. nov.

Diagnosis of the genus. Head elongate, opisthognathous, with strongly protruding antennal shelf. Ventral margin of frons at least with lateral tubercles, parafrontal carina absent. Malar sulcus absent.

Tentorial pits present, large. Pleurostoma positioned at right angles to each other ( Fig. 1C, D ), mandibles projecting postero-ventrally and weakly curved ( Fig. 1B, C ). Scape long, with simple apical rim. Male antennae 14-segmented with A4 modified. Postgena, propleuron and pronotum anteriorly covered by dense pubescence with foamy structures. Mesoscutum smooth, notauli absent. Scutellum with single scutellar fovea that smooth and bare inside; lateral margin of scutellar disc not carinate; posterior mesoscutellar sulcus present. Mesopleuron smooth, sternaulus absent. Metascutellum with strongly elevated lateral carina and comparably short and low median carina ( Fig. 1E ). Propodeum with strongly elevated plicae, without median carina and carina along posterior margin ( Fig. 1E ). Legs slender; femora and tibia of all legs longitudinally strigose to reticulate. Fore wing with short marginal vein; postmarginal vein absent; stigmal vein as long as wide of marginal vein medially ( Fig. 2C, D ). Metasoma behind petiole (gaster) strongly depressed, with sharp ages aside and wide laterotergite ( Fig. 2C ); three tergites present between petiole and spiracle-bearing tergite: one (T2) very long and two (T3‒ T4) short; S3 the largest sclerite while S2 small and pubescent ( Fig. 2C ); base of T2 setose, with deeply arcuated anterior margin ( Fig. 1E ) but without notches, elongate grooves, lateral carinae or blunt median process. Male with exposed 1-segmented cerci on T6 ( Fig. 2B, C ).

Remarks. Attribution of the new genus to the subfamily Ambositrinae is based on the metasoma characters: gaster strongly depressed with sharp ages aside, wide laterotergite and exposed cerci; S3 the largest sclerite while S2 small. The new genus should be assigned to the tribe Betylini (and to the group of genera without a pronotal scrobe) based on the following characters: the fore wing with Sc+R reaching of the wing anterior margin and the absence of 'anellus' on male antennae between segments A2 and A3. The new species attributed to the new genus based on unique complex of characters: construction of the mandibles and their position relative to each other; absence of notauli; reduction of median propodeal carina and median carina of metascutellum and strong expression of plicae and lateral carina of metascutellum ( Fig. 1E ); posterior margin of propodeum not defined, dorsal side of propodeum and nucha smoothly continuous; venation characters and construction of T2 base.

Etymology. The species name is a Latin noun in apposition, an anagram of the genus name Synacra (read right to left); the name refers to morphological similarity of the new genus to members of the genus Synacra Förster, 1856 ( Diapriidae , Belytinae ).

Figures

Figure 1. Arcanys rostratus sp. nov. A, whole inclusion in lateral view; B, head and antennae in lateral view; С, D, face; E, meso- and metasoma in dorso-lateral view; fs, foamy structures; lcm, lateral carina of metascutellum; mcm, median carina of metascutellum; mcp, median carina of propodeum; pl, plica. Scale bars: A, 1 mm; B, E, 0.5 mm.

Figure 2. Arcanys rostratus sp. nov. A, head and mesosoma in lateral view; B, metasoma in ventral view; С, meso- and metasoma in lateral view; D, fore wing venation; LT, laterotergite; S2 and S3, second and third sternites; mv, marginal vein; sv, stigmal vein. Scale bars 0.5 mm.