Sergyessa rusti Shcherbakov, Perkovsky, Sylvestersen & Anisyutkin, 2025

Shcherbakov, Evgeny O., Perkovsky, Evgeny E., Sylvestersen, René L. & Anisyutkin, Leonid N., 2025, The northernmost Eocene genus and species of praying mantises (Mantodea Burmeister, 1838) from Fur Formation, Denmark, Zootaxa 5715 (1), pp. 433-440 : 434-436

Sergyessa rusti Shcherbakov, Perkovsky, Sylvestersen & Anisyutkin , sp. nov.

( Fig. 1 )

Type material. Holotype: complete forewing, positive and negative impressions, Denmark, Fur Formation , Fur Island , Kaershale, pit no. 2, 56°50’17.2” N 09°02’24.3” E, Knudeklint member, ash layers -11 to -13, FUM-N 14996 ( FM 808 / 79 in Rust 1999).

Description. Forewing roughly pentagonal, with mottled pattern. The structure and pattern of the wing are very well preserved on the positive impression, whereas the venation pattern is more clearly preserved on the negative impression. ScP long, very weakly S-shaped, ending at approximately 3/4 of the wing’s length. Costal field narrow, proximally with straight cross veins, which becoming more curved and finally forming irregular double-row cells near the apex of the field. R with 5 anterior branches in total, the basalmost split at approximately 2/3 of the wing’s length, the basalmost anterior branch forked, the next split at approximately at 4/5 of the wing’s length. M with 3 terminal branches in total, the basalmost split in the basal half of the wing’s length, the first order anterior branch has a second order blind posterior branch and then forkes closer to wing’s edge, the first order posterior branch has a second order blind anterior branch. The blind branches are likely not a taxonomic character but instead a deformity of the holotype specimen ( Vršanský 2005, Vršanský et al. 2017). CuA internally pectinate: the first order anterior branch with 3 successive posterior branches, the first order posterior branch with 3 successive anterior branches, with branching positions nearly symmetrical. CuP curved along most of its course changing to straight at 4/5 of its length, making the overall shape sigmoidal. Fields between main veins of the discoidal area with double row of cells. PCu runs closely to CuP, ending in wing’s membrane at approximately 3/4 of the length of CuP. V1 almost as long as CuP, with three inflection points, approximately 2.7 times longer than V2. V2 and V3 stem directly from V1, straight. Cross-veins form double-cells rows between most of the main veins’ branches, with cells highly irregular in size and shape, making intercalaries waved. Cross-veins connecting PCu to V and branches of V elongated and sigmoidal, forming irregular network. Pseudovein present, oblique, of moderate width, situated between the branches of CuA: from slightly posteriad of the first split of the primary posterior branch to slightly anteriad of the distalmost split of the primary anterior branch, not crossing M or CuP.

Measurements, (mm). Estimated length of forewing 37, maximum width of forewing 11.

Stratigraphic range. As for the genus.

Geographic range. As for the genus.

Etymology. The specific epithet is a patronym formed from the surname of Jes Rust, a German paleoentomologist, in recognition of his great contributions to the study of Fur Formation insects.

Figures

FIGURE 1. Sergyessa rusti Shcherbakov, Perkovsky, Sylvestersen & Anisyutkin, gen. et sp. nov., holotype FUM-N 14996; 1—positive impression, air; 2—negative impression, ethanol; 3—reconstruction of wing venation. Scale bars: 4.0 mm.