Archaeocercus schuvachinae Simutnik, 2018

Simutnik, S. A. & Perkovsky, E. E., 2018, Archaeocercus gen. nov. (Hymenoptera, Chalcidoidea, Encyrtidae) from Late Eocene Rovno Amber, Zootaxa 4441 (3), pp. 543-548 : 545-547

Archaeocercus schuvachinae Simutnik sp. n.

(Figs 1–6)

Material. Holotype, K-7727, 1 ♀, Klesov, Rovno amber; Late Eocene (deposed in SIZK). The inclusion is situated close to the surface in a separate clear amber piece (about of 16 × 13 × 5 mm) of irregular parallelepiped shape. Syninclusions absent.

FIGURES 1–6. Archaeocercus schuvachinae , ♀ holotype SIZK, K-7727: 1–3 habitus: 1, dorsal (n—notaulus, c—cerca); 2, lаterаl; 3, ventrolаterаl; 4, heаd аnd аntennаe: frontolаterаl; 5, аbdomen dorsаl (с—сerса); 6, hаbitus posterodorsаl (l.с.—lineа саlvа).

Description. Body length, 1.25 mm. CΟlΟur. Thorax and gaster dark brown, head and antennae pale brown (probably it is conditioned by appearing silvery where surrounded by thin layer of air), wings hyaline, legs brown, tarsi pale brown; surface of head, mesonotum, and scutellum smooth, shiny, finely reticulate, without deep punctuation. Head. Relative measurements: head width (frontal view) 28, height 22; minimum frontovertex width 11; malar space 10; eye height 15; posterior ocellar line 10, ocular-ocellar line 1.5; scape length 12, scape width 3; other proportions of antenna as in Fig. 4; mandible wide, as in Figs. 3, 4, number of teeth unknown. MesΟsΟma. Length 0.425 mm. Relative measurements: forewing width 26, proportions of veins as in Fig. 1; hindwing width 10; distribution of setae at base of wing as in Fig. 1; mid tibia 22; midtibial spur 5. MetasΟma. Length 0.575 mm, ovipositor not protruding.

Etymology. The species is named in honor of Elizaveta Jakovlevna Schuvachina, member of the Russian Entomological Society.

Remarks. ArchaeΟcercus schuvachinae is the fifth of the 13 described Eocene species of Encyrtidae with apical cerci on the gaster. Morphology of the female gaster is usually associated with its main function, parasitization of the host. The classification of Encyrtidae proposed by V. A. Trjapitzin (1973, 1973a, 1989) and generally accepted till present is mainly based on features of the female gaster. Two subfamilies are distinguished by the presence or absence of special sclerotised stripes called the “paratergites”, which connect the outer plates of the ovipositor with the last tergite of the gaster in Tetracneminae . A second major character is the presence or absence of the filum spinosum – special locking setae on the disk of the forewing. Sharkov (1988) and Trjapitzin (1989) included the tribes Quadrencyrtini and Oriencyrtini in the subfamily Tetracneminae based on the presence of paratergites in their representatives. Noyes & Hayat (1994) considered that the paratergites of Quadrencyrtus , EucΟccidΟphagus and Oriencyrtus are not homologous with those of Tetracneminae . These genera are most closely related to AphycΟides, which is placed in Encyrtinae (tribe Microteryni Trjapitzin 1989), and they appear to be basal groups in Encyrtidae ( Noyes & Hayat 1994) .

It should be noted that the combination of the apical position of cerci and the absence of fillum spinosum occurs in all known Eocene encyrtids. The presence and structure of paratergites in ArchaeΟcercus, as well as in other fossil genera, are unknown. The use of new technologies, such as Synchrotron X-ray microtomography, is expected to clarify the position of these taxa.