Plesiomyrmex tubulatus, Dlussky & Radchenko, 2009

Dlussky, Gennady M. & Radchenko, Alexander G., 2009, Two new primitive ant genera from the late Eocene European ambers, Acta Palaeontologica Polonica 54 (3), pp. 435-441 : 439

Plesiomyrmex tubulatus sp. nov.

Fig. 2.

Etymology: From Latin tuba —tube, which refers to the peculiar character of the antennal insertion.

Holotype: GZG.BST.27.193, male, complete specimen.

Type locality and horizon: Unknown locality in Saxony, Germany.

Type horizon: Bitterfeld Amber, late Eocene.

Diagnosis.—As for genus.

Description.—Total length: ca. 5.2 mm. The new species is characterised by the following features: head length subequal to its width, widely and regularly rounded above the eyes. Clypeus wide and short, its anterior margin slightly convex and very shallowly notched medially, but not bicarinate. Eyes big, their maximal diameter ca. 2.5 times smaller than length of head. Ocelli well developed, big. Lengths of 2 nd to 12 th funicular segments are 0.24, 0.25, 0.26, 0.28, 0.26, 0.25, 0.25, 0.24, 0.20, 0.20, 0.35 mm. Mesosoma relatively long, scutum slightly convex (seen in profile); dorsal surface of propodeum declined posteriorly, somewhat longer than its declivitous face, propodeal lobes rounded. Scutum not wide, 1.5 times longer than total length of scutum and scutellum. Petiole quite long and low, 1.75 times longer than height, its anterior face not steep, almost straight, so that peduncle does not distinctly separate from widely rounded node; postpetiole subglobular, somewhat longer than its height and higher than petiole. Pygidium convex, without any additional structures, stipes of genitalia wide, not curved, broadly rounded at the apex, with numerous short erect hairs. Cerci are absent. Legs are long and slender. Lower part of frons between antennal insertions with 3 transversal rugulae, frons with longitudinal striation, surface between clypeus and lateral ocelli with semiconcentric rugulae; whole head dorsum additionally with fine superficial reticulation. Scutum and scutellum with fine reticulation. Sculpture of mesopleura, propodeum and waist is barely visible, but seems to be striato−punctated, nevertheless not coarse. Gaster is smooth and shiny. Head margins, scutum and scutellum with quite long, abundant semierect hairs. Petiole with a few standing hairs (those on postpetiole are invisible), gaster with sparse standing hairs. Legs with short subdecumbent pilosity. Forewing: vein section 1RS is much shorter than section 1M. Cells rm and mcu about twice longer than wide. Workers and queens are unknown.

Dimensions and indices.—HL = 0.80, HW = 0.79, SL = 0.18, OL = 0.33, PL = 0.53, PW = 0.25, PH = 0.30, PPL = 0.33, PPW = 0.30, PPH = 0.40, AL = 1.88, AH = 1.40, SCW = 0.85, SCL = 1.28, HTL = 1.23 mm; CI = 1.01, SI 1 = 0.219, SI 2 = 0.222, OI 1 = 0.406, OI 2 = 0.413, PI 1 = 1.75, PI 2 = 0.67, PI 3 = 0.32, PPI 1 = 0.81, PPI 2 = 0.41, PPI 3 = 0.38, PPI 4 = 1.20, AI = 1.34, SCI = 1.51, HTI = 1.53; Icu = 1.7; Icua = 1.5.