Rovnodryinini, Olmi & Guglielmino & Vasilenko & Perkovsky, 2022

Olmi, Massimo, Guglielmino, Adalgisa, Vasilenko, Dmitry V. & Perkovsky, Evgeny E., 2022, Discovery of the first apterous pincer wasp from amber, with description of a new tribe, genus and species of Apodryininae (Hymenoptera, Dryinidae), Zootaxa 5162 (1), pp. 54-66 : 55

Tribe Rovnodryinini trib. nov.

Type genus: Rovnodryinus gen. nov.

Diagnosis. Female ( Figs 1A, B ): apterous ( Figs 1A, B ); antennomeres 3–10 with ADOs; head hypognathous ( Fig. 1D ), with ocelli situated in anterior half of face not very far from clypeus ( Figs 1C, D ); occipital carina complete ( Figs 1A, C, D ); mesosoma almost completely composed of fused segments ( Figs 1A , 2C ); in mesosoma, only propleuron mobile and articulated with rest of mesosoma ( Fig. 2C ); protarsus chelate ( Fig. 3A ); chela with rudimentary claw ( Figs 3B , 4A ); tibial spurs 1/0/2. Male: unknown.

Distribution. Only known from Rovno amber.

Hosts. Unknown.

World species. One species is known.

World genera. One.

Remarks. The tribe Rovnodryinini is known only as fossil in amber. It is characterized by two lateral ocelli ( Figs 1C, D ) located just posteriorly to the antennal toruli, especially not far from the clypeus. The ocelli are located on the anterior half of the face, on the border of the frons and vertex: just the vertex is very long, longer than that of a hornet. This position of the ocelli is absolutely unusual in the Hymenoptera . Usually, in fact, the ocelli are located in the posterior half of the face. Another anomaly is the number of the ocelli (two), whereas in Dryinidae there are no ocelli (as in females of Apodryininae ) or three ocelli situated in the posterior half of the frons, as in all males and remaining subfamilies. Really, there is a small doubt about a third ocellus (median ocellus), because photos of the head in frontal view do not show clearly the anterior third of the frons between the antennal toruli (because an optical distortion caused by the amber). However, at the stereomicroscope, this area is more visible and does not show the median ocellus, in addition, a third ocellus located close to the clypeus appears improbable. Furthermore, the authors discussed a lot about the possibility that the supposed ocelli were really air bubbles, because they are covered by a milk-like substance (common on inclusions in succinite ambers), that conceals the ocelli. However, we excluded this option, because the ocelli are perfectly symmetrical and compatible and no other similar structures are present on the face. Unluckily, it is not possible to show the ocelli symmetry by a photo, because of an optical distortion caused by the amber. However, at the stereomicroscope the symmetry is distinctly visible.

Figures

FIGURE 1. Rovnodryinus khomychi, ♀ holotype. A, latero-ventral view; B, latero-dorsal view; C, head and pronotum in laterodorsal view; D, head and propleuron in ventral view. oc = ocellus. Scale bar: 2.3 mm for A, 2.1 mm for B, 0.5 mm for C, 0.6 mm for D.

FIGURE 2. Rovnodryinus khomychi, ♀ holotype.A, antennae; B, flagellomeres 1 and 2; C, mesosoma in lateral view; D, flagel- lomere 4. a = ADO. Scale bar: 0.9 mm for A, 0.01 mm for B, 0.9 mm for C, 0.06 mm for D.

FIGURE 3. Rovnodryinus khomychi, ♀ holotype: A, protarsus; B, chela. Apogonatopus edaphicus, ♀ paratype from Madagas- car, Ambilanivy forest: C, dorsal view; D, lateral view. Scale bar: 0.6 mm for A, 0.2 mm for B, 1.4 mm for C and D.

FIGURE 4. Chelae. A, Rovnodryinus khomychi, ♀ holotype. B, Apogonatopus edaphicus, ♀ holotype. ar = arolium; ec = en- larged claw; rc = rudimentary claw; t = protarsomere 5. Apexes of chela A dotted because not visible through the amber. Scale bar: 0.1 mm for A, 0.04 mm for B.