Ambositra bicarinata Chemyreva, 2024

Chemyreva, Vasilisa G., Vasilenko, Dmitry V. & Perkovsky, Evgeny E., 2024, ‘ Where there are many cattle’ in the Eocene of Ukraine: Review of Ambositra Masner (Hymenoptera, Diapriidae, Ambositrinae) from Rovno amber, with the description of three new species, Zootaxa 5446 (4), pp. 499-516 : 504-505

Ambositra bicarinata Chemyreva sp. nov.

( Figs 4 , 5 )

Holotype: ♂, SIZK GU-268 , Gulyanka, Zhitomir Oblast, Rovno amber, late Eocene , Priabonian. Amber fragment with holotype is a parallelepiped, sized 4.0: 2.8: 1.0 mm.

Paratypes (all from the same piece as the holotype): ♂, SIZK GU-270 ; ♂, SIZK GU-269 ; ♂♂, SIZK GU-267 (two inclusions) ; ♂♂, SIZK GU-273 (five inclusions).

Diagnosis. The male of A. bicarinata sp. nov. differs from all other known Ambositra species by the following combination of characters: head 1.2 times as long as wide and slightly higher than width (13: 12); eye twice as high as malar distance; gena behind eye about 0.8 times as long as width of eye in dorsal view; occipital carina bare dorsally, covered with foamy structures and setae laterally; scutellum with posterior scutellar pits; epicnemial pit absent; metapleuron and lateral side of propodeum bare medially and setose otherwise ( Fig. 4C ); distal end of submarginal vein situated very close to anterior margin of the wing ( Fig. 5C ); A1 shorter than head, A3 about 1.5 times as long as A4, both with carinae; A4 with emargination and carina developed in 0.7 of the segment length.

Description. Male. Body length 1.6 mm; fore wing length 1.6 mm; antennae length about 1.5 mm.

Head. Head 1.1 times as long as wide, smooth, with few sparse setae on it when viewed dorsally. Ocelli small, POL: OD about 1.0, POL: OOL 0.6. Antennal shelf strongly prominent, antennal sockets broadened medially in frontal and lateral view, widely separated ventrally and smooth in frontal view. Face covered with scattered suberect setae. Postantennal excavation large and densely setose inside. Ventral margin of frons without median process and with prominent lateral processes, not touching walls of antennal sockets. Eyes oval, bare, 0.5 times as high as height of head.

Antennae. Antenna filiform, homogeneously pubescent. Scape as long as A3, A3 2.7 times as long as A2 and 5 times as long as wide, with short carina developed in distal part of the segment; A4 0.6 times as long as A3, broadened at mid-length and with carina on this projection ( Fig. 5A ); A5‒A13 elongate, about 2.7 times as long as wide; A14 0.8 times as long as A3 but longer than all other flagellomeres.

Mesosoma. Pronotal collar very short, vertical; lateral pronotum smooth and mainly glabrous; collar and lateral pronotum anteriorly covered with dense woolly pubescence. Mesoscutum as long as its maximum width, weakly convex, smooth, with few scattered long suberect setae. Scutellum 1.7 times as wide as long; anterior scutellar pit 0.3 times as wide as scutellum; axilla smooth; axillar process straight, shorter than shortest distance between it and anterior scutellar pit; scutellar disk weakly convex, with distinct posterior mesoscutellar sulcus, lateral rim and axillar depression smooth. Mesopleuron smooth and glabrous laterally, pubescent ventrally; subalar furrow narrow and bare. Metanotum sparsely pubescent; metanotal trough smooth; metascutellum with high median and lateral carinae, median one the highest. Metapleuron with anteroventral metapleural pit pubescent inside; ventral side of metapleuron with foamy structures. Propodeum invisible dorsally, lateral side of it bare medially and setose otherwise. Fore wing 3.3 times as long as its maximum width.

Metasoma. Petiole entirely pubescent and with foamy structures ventrally; cylindrical, about 2.2 times as long as wide in lateral view, covered with deep grooves. Metasoma behind petiole 1.3 times as long as mesosoma, strongly depressed. Base of T2 invisible, posterior part of it smooth and bare; T3 and T4 short, equal in length; T5 1.8 times as long as T4; T6 small and hidden under T5, with one segmented cerci. S2 small and densely covered with long setae; S3 the largest sternite, densely pubescent anteriorly, smooth and with few scattered suberect setae posteriorly ( Fig. 5B ); S4‒S6 short and equal in length; S7 1.4 times as long as S6; S8 sub-triangular. T3‒T5 and S4‒S8 all covered with few scattered long suberect setae.

Etymology. The species name refers to the presence of two well-developed carinae on the male A3 and A4.

Figures

FIGURE 4. Ambositra bicarinata, male, holotype. A, B—whole insect in dorsal (A) and lateral (B) views; C—head and mesosoma in lateral view. Scale bar: A, B—0.5 mm; C—0.3 mm.

FIGURE 5. Ambositra bicarinata, male, holotype. A—antenna, head and mesosoma in dorsal view; B—whole body in ventral view; C—fore wing venation; D—mid-femora. Scale bar 0.3 mm.