Proceratium petrosum, Dlussky & Rasnitsyn & Perfilieva, 2015

Dlussky, G. M., Rasnitsyn, A. P. & Perfilieva, K. S., 2015, The Ants (Hymenoptera: Formicidae) of Bol’shaya Svetlovodnaya (Late Eocene of Sikhote-Alin, Russian Far East), Caucasian Entomological Bulletin 11 (1), pp. 131-152 : 143

Proceratium petrosum sp. n.

( Fig. 24, 25)

Material. Holotype PIN 3429/103, dorsal imprint of male.

Description. Male. Body length 7.5mm.Head with gradually rounded occipital margin, without occipital corners. Head including eyes 1.08times as wide as long. Eyes large, convex; head 2.2times as long as maximum eye diameter.Ocelli large.Mesosoma elongate, 1.7 times as long as wide. Petiole with node. Hind tibia with 1pectinate spur. 1st gastral (abdominal III) segment 0.57times as long, and 0.78 times as wide as 2nd (abdominal IV) segment. Forewing with closed cells 1+2r+rm and mcu. Cell 1+2r+rm big, 1.9times as long as wide. Transverse 2r-rs elongated and inclined. Cell mcu quadrangular, nearly twice as long as wide. Sectiom1M 1.35 times as long as 1RS. The meeting of crossvein cu-a and M+Cu is proximal to the 1M and 1Cu fork, being separated from it by a distance approximately equal to vein width.

Measurements of holotype, mm: AL 2.9; HL 1.3; HW(including eyes)1.4; ED0.58; PtL0.61; FWL4.4.

Comparison. A comparison with the recent species of Proceratium is not possible because males of this genus are poorly known. The only known male of fossil species is P.eocenicum described from Baltic amber [ Dlussky, 2009]. It differs from P.petrosum in size (body length 2.2–2.7mm) and closed cell3r of forewing.

Etymology. From the Latinized Greek petros (stone).