Gesomyrmex

Dlussky, Gennady M., Wappler, Torsten & Wedmann, Sonja, 2009, Fossil ants of the genus Gesomyrmex Mayr (Hymenoptera, Formicidae) from the Eocene of Europe and remarks on the evolution of arboreal ant communities, Zootaxa 2031 (1), pp. 1-20 : 13-14

Key for determination of gynes of Gesomyrmex

(gynes of extant species G. chaperi , G. howardi and G. kalshoveni unknown)

1. Anterior margin of clypeus straight or feebly concave ( Figs. 3 B, 5A, 5B).................................................................. 2

- Anterior margin of clypeus projects as rounded lobe ( Figs. 3 A, 4A–4C). Fossil species............................................ 4

2. Head more than 1.4 times longer than wide ( Figs. 5 A, 5B). Living species................................................................ 3

- Head about 1.2 times longer than wide ( Fig. 3 B). BL about 13 mm. Eckfeld, middle Eocene...... G. flavescens sp. n.

3. Propodeum gradually rounded in side view. Eyes larger: head less than 3 times longer than maximum eye diameter. Posterior margin feebly concave ( Fig. 5 A). BL about 8.5 mm. Philippines............................. G. luzonensis (Wheeler)

- Propodeum angulate in side view. Eyes smaller: head more than 3 times longer than maximum eye diameter. Posterior margin straight. ( Fig. 5 B). BL about 9.5 mm. Vietnam........................................................ G. tobiasi Dubovikoff

4. Head subrectangular, with feebly concave posterior margin, about 1.1 times longer than wide ( Fig. 4 B). BL 7–9 mm. Messel, middle Eocene.................................................................................................................. G. breviceps sp. nov.

- Head more than 1.2 times longer than wide ................................................................................................................. 5

5. Head subtrapezoid, broader in its anterior part than in its posterior part, with gradually rounded posterior margin, without posterolateral corners. Eyes comparatively small: head 4.4 times longer than maximum eye diameter ( Fig. 4 C). Messel, middle Eocene........................................................................................................... G. curiosus sp. nov. - Head subrectangular with distinctive rounded posterolateral corners ( Figs. 2 A, 3A, 4A)........................................... 6

6. Eyes comparatively small: head 4.7 times longer than maximum eye diameter. Scape comparatively short: head 4.4 times longer than scape. Baltic, Bitterfeld, Rovno and Scandinavian ambers, late Eocene............... G. henschei Mayr

- Head 2.5 to 3 times longer than maximum eye diameter, and 3 to 3.3 times longer than scape ( Figs. 3 A, 5A). ........ 7 7. Posterior margin distinctly concave ( Fig. 4 A). Head and most part of mesosoma yellowish brown, mandibles, central part of scutum, whole scutellum and median parts of gastral tergites dark brown. BL 4.8 mm. Messel, middle Eocene............................................................................................................................................... G. pulcher sp. nov.

- Posterior margin feebly convex (Fig. 8A. Whole body black. BL 9–10 mm. Eckfeld, middle Eocene. ...................... ................................................................................................................................................... G. germanicus sp. nov.

Figures

FIGURE 2. Gesomyrmex hoernesi Mayr. (A) gyne PMHU. 7 / 229. (B) major worker SIZK. K- 419. (C) minor worker GMUG. BST. 04207; (D – F) male MKC. F- 010: (D) general view of inclusion, (E) fore wing, (F) genitals. Scale bars = 1 mm.

FIGURE 3. Gesomyrmex species from Eckfeld maar. (A) G. germanicus sp. nov., gyne, holotype PE- 1997 / 29. (B) G. flavescens sp. n., gyne, holotype PE- 2000 / 14. Scale bars = 1 mm.

FIGURE 4. Gesomyrmex species from Messel. (A) G. p u l c h e r sp. nov., gyne, holotype MeI 10999. (B) G. breviceps sp. nov., gyne, holotype MeI 2305. (C) G. curiosus sp. nov., head of gyne, holotype MeI 11953. Scale bars = 1 mm.

FIGURE 5. Heads of gynes of extant species of Gesomyrmex. (A) G. luzonensis (Wheeler) (after Wheeler 1916). (B) G. tobiasi Dubovikoff (from Dubovikoff 2004). Scale bars = 1 mm.