Brachysyntexis tenebrosa Kopylov, 2018

Kopylov, Dmitry S., 2018, Forgotten giants: new Anaxyelidae (Hymenoptera) from the Jurassic of Karatau, Zootaxa 4514 (3), pp. 332-340 : 333-334

Brachysyntexis tenebrosa Kopylov , sp. nov.

( Figs. 1 , 4A )

Etymology. The name is the Latin adjective ‘tenebrosus’ (dark) due to the dark colour of the species.

Material. Holotype: PIN, no. 2066/3344 from Karatau ( Kazakhstan), part and counterpart, sex unknown. Good state of preservation of fore and hind wings, however, all four wings are superimposed on the body, which hinders the interpretation. The head is well-preserved, the teeth of the mandibles are distinguishable; the antennae are not totally preserved; the right mandible has preserved well, the left is distinguishable, though in somewhat worse condition, and is in all probability damaged; the thorax is destructed, however the structure of mesonotum can be identified; the abdomen and the legs are not preserved.

Description. Whole body, antennomeres, wing veins dark, wing membrane not coloured, eye orbits very dark. 1 Head elongated-oval; eyes large, eye height equals 0.7 of the head height. Antennae attached at the level of the lower infraorbital rim; scape not big, rounded; pedicel slightly swollen, little different form from the following flagellomeres; flagellomeres gradually increase from the base, the largest are the second and the third: the ratio of lengths of the preserved antennomeres is 1.0/1.1/1.3/1.2/1.2; the thicknesses are related as 1.0/1.0/1.3/1.3/1.0 (pedicel/flagellomeres 1/2/3/4). Mandible with three teeth: upper tooth rounded, widely separated from lower ones; two lower teeth sharp and close-set. Mesonotum without any apparent sculpture (likely lost during fossilization), with well-developed longitudinal and V-shaped (scuto-scutellar) sulci and notauli; the ratio of lengths of prescutum/longitudinal sulci between the prescutum and scutellum/scutellum is 2.4/1.0/5.6. Mesoscutellum with pointed front edge, narrow and long, 2.0 × as long as wide. Fore wing with costal cell narrow; 1-Rs slightly bended downwards, 3.3 × as long as 1-M; Rs+M slightly shorter than 2-M; 1r-rs straight, 1.4 × as long as 2-Rs; 2r-rs 1.5 × as long as 1r-rs, issues from pterostigma at its midlength, rear edge of pterostigma not bent near 2r-rs; cell 1r 1.2 × as long as 2r; cell 2r 2.1 × as long as wide; 4+5-Rs 1.6 × as long as 3-Rs; 3+4-M 2.1 × as long as 5-M; 5-M approximately 1.1 × as long as 3r-m, 3r-m proclined; 2-Cu 1.5 × as long as 1-Cu; 1cu-a arched, 2cu-a slightly sshaped; 3-1A 1.4 × as long as 2-1A. Hind wing with 1-Rs approximately 1.2 × as long as 2-Rs; r-m located distal to m-cu, r-m 1.3 × as long as 2-M; cell 1r 4.6 × as long as wide and 1.7 × as long as 1mcu; cell 1mcu 2.6 × as long as wide.

Measurements (in mm): estimated length of the body 17; head height 3.0; length of the fore wing (approximately) 11.5, width 3.6.

Comparison. B. tenebrosa differs from the other Brachysyntexis species in the shape of the pterostigma (the other species have the rear edge of the pterostigma bent near 2r-rs) and the length of vein 5-M (in other species 5- M is not longer than 3r-m), as well as in its large size. Considering the length of the fore wing, B. tenebrosa is the largest representative of Brachysyntexis . It also differs from B. brachyura , B. micrura , and B. robusta in the long mesoscutellum; from B. nova in the long cell 1r; from B. brachyura , B. micrura , and B. nova in the length of Rs+M; from B. micrura and B. robusta in the length of 1r-rs; from B. brachyura and B. nova the proclined 3r-m; from B. brachyura , B. nova, and B. robusta by the respective position of r-m and m-cu on the hind wing. In the description of B. nova by Rasnitsyn (1969), vein r-m of the hind wing was not defined. In reality, it is present on the holotype and is located a bit basal of m-cu.

Figures

FIGURE 1. Brachysyntexis tenebrosa sp. nov., holotype PIN, no. 2066/3344: A. habitus draw, B. separated wings (showing names of the veins used in this paper). Karatau; Kazakhstan, Upper-Middle Jurassic. Scale bar 5 mm.

FIGURE 4. New species of Anaxyelidae from Karatau: A. Brachysyntexis tenebrosa sp. nov., holotype PIN, no. 2066/3344, B. Brachysyntexis tigris sp. nov., holotype: PIN, no. 2997/648, C—Kulbastavia grandis sp. nov., holotype: PIN, no. 2997/5000. Karatau; Kazakhstan, Upper-Middle Jurassic. Scale bars 5 mm.