Magadanobracon zherikhini, Belokobylskij, 2012

Belokobylskij, Sergey A., 2012, Cretaceous braconid wasps from the Magadan Province of Russia, Acta Palaeontologica Polonica 57 (2), pp. 351-361 : 354-357

Magadanobracon zherikhini sp. nov.

Figs. 3 , 4.

Etymology: After Vladimir Vasilievich Zherikhin, well−known Russian palaeoentomologist and the collector of this specimen.

Holotype: male (?), PIN, 3901/80 (part), PIN, 3901/79 (counterpart); wasp in dorsoventral aspect lacking antenna excepting its bases, fore and middle legs, right fore wing, almost all hind wings, and metasomal apex.

Type locality: Obeshchayushchiy fossil site, Magadan Province, Russia.

Type horizon: Cenomanian, Late Cretaceous , 99.6±0.9–93.5 ±0.8 Myr, tuffaceous mudstone of the lacustrine Ola Formation.

Diagnosis.—This species is very similar to M. rasnitsyni sp. nov., but differs in having the hind tibia weakly widened, first metasomal segment with keels distinctly S−shaped, recurrent vein (m−cu) more strongly postfurcal, and fore wing metacarp (1−R1) longer.

Description.—Male. Body length 6.4 mm; mesosoma 2.2– 2.3 mm, metasoma about 3.5 mm; first tergite 1.25 mm; fore wing 6.1–6.2 mm.

Head: More or less transverse, about 1.6 times as wide as long medially, roundly narrowed behind eyes. Head 1.35 times wider than its median length. Maximum diameter of ocellus equal to diameter of antennal socket. Scape rather wide, about 1.5 times longer than its width. Flagellar segments slender.

Mesosoma: 1.8–1.9 times longer than maximum width at level of tegulae, 0.4 times as long as fore wing. Mesoscutum distinctly rounded apically, 1.2 times as wide as long medially; median lobe convex. Notauli deep and complete, joined before posterior margin of mesoscutum. Prescutellar depression deep, long, smooth, with median carina. Metanotum rather long. Propodeum with delineated areas, mostly sculptured. Sternaulus (or possibly at least distinct fold in lower part of metapleuron) rather deep, long, and smooth.

Fore wing: Length 2.8 times longer than maximum width. Costal vein (C+SC+R) thick, with rather distinct suture separated costa (C) and subcosta (SC). Pterostigma subtriangular, 2.6 times longer than maximum width. Radial (marginal) cell almost not shortened, wide, pointed apically, 2.3 times longer than its maximum width. Metacarp (1−R1) 1.25 times longer than pterostigma. Radial vein (r) arising almost from or weakly behind middle of pterostigma, distance from this vein to apex of pterostigma along its inner side 0.7 times as

http://dx.doi.org/10.4202/app.2010.0120

long as distance from vein to base of pterostigma. First radial abscissa (r) about 0.6 times as long as maximum width of pterostigma, forming very obtuse angle with second abscissa (3−SR). Second radial abscissa (3−SR) 2.2 times longer than first abscissa (r), 0.4 times as long as the straight third abscissa (SR1), 0.8 times as long as first radiomedial vein (2−SR), 1.5 times longer than second radiomedial vein (r−m). Second radiomedial (submarginal) cell not narrowed distally, about twice as long as maximum width, 1.3 times longer than brachial (subdiscal) cell. Recurrent vein (m−cu) 3.5 times longer than third medial abscissa (2−SR+M), 0.6 times as long as first radiomedial vein (2−SR), 0.55 times as long as second (posterior) abscissa of basal vein (1−M). Discoidal (discal) cell 1.2 times longer than wide. Nervulus (cu−a) inclivous, distance from nervulus (cu−a) to basal vein (1−M) 0.4 times as long as nervulus (cu−a) length. Brachial (subdiscal) cell about 3.0 times longer than its maximum width. Mediocubital vein (M+CU1) straight.

1 mm 1 mm

Legs: Fore femur rather thick. Middle (?) femur 4.2 times longer than its maximum width. Hind tibia basally slender, weakly widened distally.

Metasoma: First tergite wide, distinctly and curvedly widened towards apex, with rather distinct and wide subbasal tubercles, with more or less distinct dorsope; dorsal carinae distinct, complete, subparallel in basal half and weakly roundly widened in apical half; more or less sculptured at least in apical half. Apical width of first tergite about 2.0 times its basal width; length of first tergite 0.7–0.8 times its apical width. Second tergite with narrow basal area, or possibly it is wide gape between first and second tergites; tergite smooth, rather short, 0.35 times as long as basal width, about as long as smooth third tergite.

Colour: Head and mesosoma black, metasoma brown or black. Middle femur dark brown, hind tibia pale. Fore wing possibly faintly or very faintly infuscate, especially along veins. Pterostigma dark brown, pale in basal 0.2 and apically; veins brown.

Figures

Fig. 3. Photographs of braconid wasp Magadanobracon zherikhini gen. et sp. nov., holotype of male (?), Obeshchayushchiy fossil site (Magadan Province, Russia), Earliest Upper Cretaceous. A. PIN, 3901/79, counterpart; A1, habitus; A2, head, mesosoma, and basal part of metasoma. B. PIN, 3901/80, part; B1, habitus (part); B2, fore wing (part); B3, body (part). Scale bars 1 mm.