Gesomyrmex curiosus ^HNS sp. nov.

(Fig. 4C and Fig. 6H)

Derivation of the name. Curiosus is Latin for funny.

Holotype. SMF Mei 11953 (head of $).

Type locality and horizon. Grube Messel, Hesse, Germany. Messel formation, middle Eocene, ca. 47 Ma (Mertz & Renne 2005).

Description. Gyne. Head subtrapezoid, broader in the front than in the back, with gradually rounded posterior margin, without posterolateral corners. Anterior clypeal margin weakly projected, forms a small rounded lobe. Eyes comparatively small: head 4.4 times longer than maximum eye diameter. Frontal carinae short, divergent, reach the anterior margin of eye. Scape does not reach posterior margin of eye; head 3.5 times longer than scape. Mandible triangular, with 5 massive blunt teeth. Most part of the head brownish yellow, anterior part of head and spot near ocelli more dark, mandibles dark brown.

Measurements (in mm). Holotype Mei 11953: HL 2.3, HW 1.6, SL 0.65, ED 0.52.

Comments. Only the head of the unique holotype specimen is well preserved. However it is very different from all fossil and living species.