Two new genera of Encyrtidae (Hymenoptera, Chalcidoidea) with reduced ovipositor sheaths

Archaeocercoides puchkovi Simutnik, gen. et sp.nov., and Rovnopositor voblenkoi Simutnik, gen. et sp.nov., are described and illustrated based on female specimens from late Eocene Rovno amber. Like most previously described Eocene Encyrtidae, the new taxa differ from the majority of extant encyrtids by the apical or nearly apical position of the cerci, the short radicle, and the long marginal vein of the forewing. Both new genera are characterized by a strongly reduced ovipositor sheaths but long and upwardly bent ovipositor stylets (in the “ovipositing position”), a stigmal vein with a long uncus, and the absence of a filum spinosum. The new genera differ from each other in the width of frontovertex, the location of the cerci, and the lengths of funicular segments and marginal vein. A. puchkovi was fossilized near a Coccoidea crawler.


Material and methods
The studied specimens are housed in the collection of the Schmalhausen Institute of Zoology of the National Academy of Sciences of Ukraine, Kiev (SIZK). The amber pieces containing the holotypes were found in the Varash District of Rovno Region (UA-28099) (Yamamoto et al. 2022 and references therein), and in Pugach quarry (Klesov) (fauna of the deposit reviewed in Mitov et al. 2021), Sarny District, Rovno Region (K-9948). The Varash specimen was cut from the big piece, the Klesov specimen is part of an unbiased sample (Perkovsky et al. 2012), bought from the Ukramber factory (Rovno); the raw weight of clear piece 2-1410 was 7.3 g, size 45×25×15 mm.
Photographs were taken using a Leica Z16 APO stereomicroscope equipped with a Leica DFC 450 camera and processed with LAS Core and Adobe Photoshop software (brightness and contrast only). To improve imaging, we applied sucrose syrup of approximately the same refractive index as the amber itself and then placed a glass cover slip on top. To photograph some of the structures, the cover slip was placed at different angles to the surface of the amber (Fig. 1A). Afterwards, the syrup was removed by warm water.
Terminology and abbreviations follow Sharkov (1985), Gibson (1997), and Heraty et al. (2013). The following abbreviations are used in the text: F1, F2, etc. = funicular segments 1, 2, etc.; LOL = minimum distance between the anterior ocellus and a posterior ocellus; Mt1, Mt2, etc. = metasomal terga, numbering starts from petiole (Mt1); OOL = minimum distance between an eye margin and the adjacent posterior ocellus; OCL = minimum distance between a posterior ocellus and the occipital margin; POL = minimum distance between the posterior ocelli. Diagnosis. Habitus not 'encyrtiform', body not compact, slightly elongated and flattened; minimum distance between eyes almost 0.5× head width; frontovertex broader than long, ocelli in strongly obtuse triangle, posterior ocelli elliptical in dorsal view; all 6 funicular segments transverse, first funicular segment ring-like; clava only slightly shorter than funicle, about 2.2× as long as broad; mesoscutum and scutellum flat, notaular lines absent; scutellum as long as broad, flat, and as long as mesoscutum; marginal vein more than three times as long as broad, shorter than postmarginal one; covering setae (sensu Sharkov 1985) along basal margin of linea calva present, poorlydeveloped, but much longer than in Archaeocercus ( . However, the ovipositor, partly, is in the "laying or ovipositing position". Therefore, when it was not in the ovipositing position, it would be mostly retracted and enclosed within the hypopygium and not really truly exserted. The hypopygium may also slightly not reach to the apex of the gaster.

Systematic paleontology
Remarks. The new genus is very similar to Archaeocercus Simutnik, 2018, but differs by the OOL being equal to the posterior ocellar diameter, the posterior ocelli are relatively larger and elliptical in dorsal view; the clava is more narrow and elongated; the parastigma is not expanded (Archaeocercus with distinct parastigma, see figs 1, 2, 6 in Simutnik and Perkovsky 2018a); notauli are absent; the scutellum is longer, as broad as long, not shorter than the mesoscutum; the inner angles of the axillae are wider; the covering setae along linea calva are short but distinctly present; and by its long ovipositor stylet (in the "ovipositing position")(see figs 1-6 in Simutnik and Perkovsky 2018a). Trjapitzion Simutnik, 2018 clearly differs from the new genus in a high interantennal prominence, strongly expanded parastigma, strongly widened scape and mandible, and in very short legs, especially tarsi (figs 2, 3, 6 in Simutnik and Perkovsky 2018b).

Archaeocercoides puchkovi
Material. Holotype, SIZK, no. UA-28099, 1♀, Varash District, Rovno Region, Ukraine; Rovno amber; late Eocene. The inclusion is in a yellow and clear piece of amber in a shape of parallelepiped (ca. 40 × 10 × 9 mm), one side of which contains a layer of organic residues. All body parts are preserved.
Description. Female. Habitus as in Figs 1B, 2C. Body not compact, slightly elongated and flattened. Body length 1.2 mm.
Gaster. As long as mesosoma, polygonal reticulate equal dorsally and ventrally, apical margins of metasomal terga straight, parallel; paratergites and cercal setae not visible; ovipositor stylet combined from 1 st and 2 nd valvulae (stylet suture presumably visible in Etymology. The name of the genus is a combination of the words "Rovno" and "ovipositor". The new genus is distinguished by an unusual ovipositor structure. Gender masculine. Diagnosis. Habitus not 'encyrtiform', body not compact, not flattened; ocelli in almost right angled triangle (Fig. 5B), posterior ocelli elliptical in dorsal view; frontovertex about as long as broad; flagellum long, first funicular segment 1.5× as long as broad, funicle without transverse segments; clava slightly longer than F4-F6 combined, 2.5× as long as broad; mesoscutum and scutellum convex, notauli absent; scutellum as broad as long, and as long as mesoscutum; marginal vein relatively short, twice as long as broad, and one-third as long as postmarginal vein; setae along basal margin of linea calva short; filum spinosum absent; parastigma almost not widened; strigil present, well-developed; cerci slightly advanced toward gastral base, with long cercal setae (Fig. 5D: cers); apex of hypopygium reaching way past apex of gaster (in ovipositing position, Fig. 5A,D: hyp), lateral margins of hypopygium bare, without row of setae; protruding part of ovipositor stylet stout, upwardly bent (in ovipositing position); ovipositor sheaths strongly reduced, not visible in lateral view.
Remarks. The new genus differs from Archaeocercoides in the right angled ocellar angle; the frontovertex is about as long as broad; its long flagellum, the first funicular segment being longer than broad, the funicle without transverse segments; the clava slightly longer than F4-F6 combined, 2.5× as long as broad; the relatively short marginal vein, twice as long as broad and one-third length of postmarginal vein; the convex mesoscutum and scutellum; the well-developed strigil; the cerci are noticeably sensillae; postmarginal vein with row of long setae; setae of marginal fringe present (Fig. 5C).
Gaster. As long as mesosoma, polygonal reticulate equal dorsally and ventrally; protruding part of ovipositor stylet approximately as long as metatarsus (in ovipositing position); suture between 1 st and 2 nd valvulae clearly visible at base and at apex of stylet (Fig. 5D).

Discussion
The new genera differ from most extant members of the family by their short radicle, long veins of the forewing, and by the apical position of the cerci. A more detailed comparison with extant genera with apical or nearly apical position of the cerci is provided by Simutnik 2021; Simutnik et al. 2021a. In particular, extant Eucoccidophagus Hoffer, 1963Aphycoides Mercet, 1921;and Prionomastix Mayr, 1876 are well distinguished from the all known extinct genera by having a very short marginal vein. Archaeocercoides, Rovnopositor, and Archaeocercus also differ from Aphycoides and Prionomastix in the absence of a filum spinosum and the shape of Mt8 ( fig. 12C in Simutnik 2021 and fig. 9 in Simutnik et al. 2021b). The venation of the forewings and the very small ovipositor sheaths in the newly described taxa most closely resemble those of Moraviella Hoffer, 1954;Monodiscodes Hoffer, 1954;Savzdargia Trjapitzin, 1979; possible, some species of Ericydnus Walker, 1837; and some other extant Tetracneminae. Savzdargia may be the "most primitive" extant Tetracnemine (Trjapitzin 1989;Noyes and Hayat 1994;J. S. Noyes pers. comm., 2022). At the same time, the paratergites (the presence of which is one of the main features of Tetracneminae) has not yet been found in fossil encyrtids, including the taxa described here. Tetracneminae is probably a more derived group -it always comes out as a derived group in DNA based phylogenetic analyses (J. S. Noyes pers. comm., 2022). Therefore, it would be premature to classify Archaeocercus, Archaeocercoides, Rovnopositor and other known fossil Encyrtidae without the filum spinosum as members of the Tetracneminae within the current concept of this subfamily. Their taxonomic placement within the family remains uncertain.