Elasmosomites primordialis Brues, 1933

Belokobylskij, Sergey A., Dubovikoff, Dmitry A., Manukyan, Andranik R. & Zharkov, Dmitry M., 2021, Braconid parasitoids of ants (Hymenoptera, Braconidae, Euphorinae, Neoneurini) from Baltic amber with a discussion of records of fossil larvae parasitizing ant workers, Journal of Hymenoptera Research 84, pp. 29-43 : 29

Elasmosomites primordialis Brues, 1933

Figs 2 , 3

Elasmosomites primordialis Brues 1933: 97; Poinar and Miller 2002: 42; Yu et al. 2016.

Material examined.

1 male, Eocene Baltic amber, # BX 9/21.2 (KAM).

Male (first description).

Body length 2.5 mm, fore wing length 1.7 mm.

Head: Short and transverse in dorsal view. Occipital carina laterally present but fine, below reaching lower margin of head, perhaps independently from hypostomal carina. Ocelli slightly enlarged, arranged in obtuse triangle with base about 1.5 times its sides. POL about 2.0 times OD. Eyes enlarged, slightly converging ventrally. Malar suture absent. Malar space short, about 0.5 times basal width of mandible. Face convex, without facial tubercles and bristles. Mandible rather long, narrow, slightly twisted, with two pointed teeth, upper tooth distinctly longer than lower tooth. Maxillary palpus rather long and slender, 6-segmented, its second segment slightly thickened. Labial palpus short, perhaps 3-segmented, but third segment very short and subglobular. Vertex and frons with distinct and dense transverse and slightly curved striae. Temple relatively wide and distinctly punctate.

Antenna: Relatively long, slightly thickened, 16-segmented, with short and very dense pale setosity, about 0.6 times as long as body. Scape longer than pedicel. Length of first flagellar segment 2.7 times its maximum apical width, 1.4 times length of second segment. Length of penultimate segment 1.7 times its width, 0.8 times length of acuminate apical segment.

Mesosoma: Mesoscutum about 1.2 times wider than its median length, distinctly and densely punctate with very short and fine submedian longitudinal carina posteriorly. Prescutellar depression (scutal sulcus) relatively short, with several sparse crenulae. Scutellum slightly convex, weakly and sparsely punctate. Mesopleuron slightly convex, mainly smooth in the middle, with fine and sparse marginal punctation. Prepectal carina present and distinct laterally, absent ventrally. Prepectus distinctly rugulose-reticulate. Subalar depression slightly concave, narrow, areolate with oblique transverse striae. Posterior mesopleural suture shallow, narrow and distinctly crenulate. Mesosternal sulcus narrow but distinct and rugose. Metapleuron anteriorly with subvertical crenulate depression, mainly rugose-areolate and with additional reticulation; metapleural lower process short, wide and nearly round distally.

Wings: Fore wing 2.6 times longer than its maximum width, with its membrane entirely and densely setose. Costal vein distinctly thickened, clearly widened towards apex. Short and vestigial costal cell present distally. Pterostigma wide and relatively short, triangular, 2.5 times longer than median width. Metacarp (1-R1) distinctly and entirely sclerotised, 0.8 times as long as pterostigma. Radial vein (r) arising from basal 0.3 of pterostigma. Radial (marginal) cell distinctly shortened, about 3.0 times longer than its maximum width. First radial abscissa (r) long and subvertical to pterostigma, 0.7 times as long as maximum width of pterostigma. Second radial abscissa (3-SR) short, 0.7 times as long as first abscissa (r), 0.5 times as long as sclerotised part of third abscissa (SR1) and 0.15 times as long as almost straight complete third abscissa (SR1), almost equal to first radiomedial vein (2-SR). Second radiomedial (submarginal) cell rather small, completely delineated by sclerotised veins, 1.7 times longer than wide. Second radiomedial vein (r-m) almost straight, slightly oblique, almost as long as first radiomedial vein (2-SR). Discoidal (discal) cell with relatively long petiole (1-SR) anteriorly, 1.6 times longer than its maximum height; parastigma enlarged. First medial abscissa (1-SR+M) very slightly sinuate. Recurrent vein (m-cu) relatively short, distinctly postfurcal, 2.5 times longer than second medial abscissa (2-SR+M), almost as long as first radiomedial vein (2-SR), about as long as second radial abscissa (3-SR). Nervulus (cu-a) distinctly postfurcal, distance (1-CU1) between nervulus (cu-a) and basal vein (1-M) 1.2 times nervulus (cu-a) length. Parallel vein (CU1a) distinctly broken basally. Hind wing poorly preserved, with 3 hamuli; its posterior margin with distinct narrow split in basal third.

Legs: Fore coxa subglobular. Short trochantellus distinctly separated in all legs. Fore femur relatively narrow, 2.8 times longer than wide, apically without tooth. Fore tibia without protuberances or processes, distinctly widened towards apex, its length 5.0 times maximum width in lateral view. Fore tarsus about as long as fore tibia. Fore tibial spur slightly curved, 0.7 times as long as fore basitarsus and 0.2 times as long as fore tibia. Tarsal segments of middle leg elongate. Hind coxa dorsally slightly concave submedially, distinctly and densely punctate, evenly convex anteriorly. Hind femur wide, elongate-oval, 3.3 times longer than its maximum width. Hind tibia distinctly widened towards apex, 4.5 times longer than maximum apical width, 1.1 times longer than femur, about as long as hind tarsus. Both spurs of hind tibia acute apically, longest spur 0.8 times as long as hind basitarsus. Hind tarsus slender, all its segments of similar width and not narrowed towards apex. All tarsal claws slender and simple.

Metasoma: About 3.0 times longer than maximum width, almost as long as mesosoma and head combined, seemingly entirely smooth and bare, only with sparse short setae in posterior thirds of third and following tergites, with spiracles situated almost at the middle of lateral parts of tergites, without separated laterotergites. First tergite widened towards apex. Suture between second and third tergites absent. Median length of second and third tergites combined about 1.3 times distal width of third tergite. Segments behind third one distinctly projected.

Colour: Body entirely black. Tegula dark brown. Wings faintly and evenly infuscate; pterostigma entirely dark brown.

Remarks.

The differences between both known species of the genus Elasmosomites are given previously after the description of the new species.

Figures

Figure 2. Elasmosomites primordialis Brues, 1933 (male, Baltic amber, # BX 9 / 21.2) A habitus, dorso-lateral view B habitus, ventro-lateral view C head, antenna and metasoma, dorsal view D head and mesosoma, ventro-lateral view E mesosoma, dorsal view F metasoma, ventral view.

Figure 3. Elasmosomites primordialis Brues, 1933 (male, Baltic amber, # BX 9 / 21.2) A fore wing B hind wing C posterior margin of hind wing.