Euponera Forel, 1891

Euponera Forel, 1891 View in CoL

( Figs 2D View Fig , 4D View Fig , 6D View Fig )

Recognition. Medium-sized ants with total body length 5.0– 6.2 mm; mandible with basal pit; petiolar sternite without posterior extension; mid- and hindtibiae with both simple and spatulate spurs.

Description. The genus includes medium-sized species. In the Japanese species queen measuring 5.0– 6.2 mm in total body length. Head 1.04–1.28 mm in width, in full-face view slightly longer than broad, with very shallowly emarginate posterior margin and shallowly convex lateral margins. Clypeus very weakly convex anteriorly with anterior margin entire. Malar space subequal to or slightly longer than half the major diameter of eye. Eye moderately large, with 12–15 ommatidia along its longest axis, with sparse hairs. Mandible subtriangular; masticatory margin with distinct teeth of variable length; basal pit present. Antennal scape reaching or slightly surpassing posterior margin of head, with sparse erect hairs and dense appressed pubescence. Mesosoma almost entirely densely sculptured and matte except for propodeal declivity, in dorsal view narrower than head; pronotum as broad as mesoscutum; promesonotal suture conspicuous. In profile view mesosoma with dorsal outline weakly arched; groove separating mesopleuron into upper and lower sections strong, with punctures on its bottom; metapleuron fused with propodeum; opening of propodeal spiracle slit-like. Petiole scale-like. Gastral constriction distinct; gastral segment II with pretergite often and presternite almost always exposed except for samples with shrunk gasters; both presclerites densely covered with fine transverse striae; cinctus differentiated from pretergite proper, very ‘narrow’, microscopically cross-ribbed. Mid- and hindtibiae with simple spur and longer pectinate spur. Hindwing jugal lobe often missing. Caste differences. Workers are slightly smaller than queens, with head width 0.90–1.17 mm (1.04–1.28 mm in the queen). The eye is much smaller and indistinct with a few ill-defined ommatidia. The posterovetral corner of subpetiolar process angulate in the worker, while subpetiolar process gradually sloping posteriad in the queen.

Remarks. In the Japanese members of this genus, the presternite of the gastral segment II is almost always extensively exposed in mounted specimens, and pretergite is also frequently exposed: these sclerites have dense regular striae. In the male the hindwing generally has a jugal lobe that is obsolete and somewhat difficult to recognize. See also OGATA (1987: 114, referred to as Trachymesopus ).

Species examined (2/2). Euponera pilosior (Wheeler, 1928) and E. sakishimensis (Terayama, 1999) .