Odontomachus Latreille, 1804

Taxonomy. The genus Odontomachus is assigned to the tribe Ponerini (Bolton 2003) .

Morphology. Workers of Vietnamese species have the following features (see also Schmidt & Shattuck 2014):

Worker monomorphic; head in full-face view subrectangular, with a constriction a little behind midlength of head; vertexal lobe well developed; vertex with a median longitudinal carina which meet the dorsalmost part of preoccipital carina; posterior face of head (inside preoccipital carina) with a pair of dark lines which meet together at or near dorsalmost part of preoccipital carina; frontal lobe horizontal, partly to largely concealing antennal insertion; antennal scrobe absent; submedian portion of clypeus weakly expanded above each mandibular base; posteromedian portion of clypeus relatively narrowly inserted between frontal lobes; mandible long and straight, inserted at middle of anterior margin of head; three apical teeth forming a fork; subapical tooth often present as an angle or small triangular tooth; masticatory margin serrate, and ventrally with a low of several long setae; antenna 12-segmented, filiform; scape slender and long; eye located on anterodorsal face of anterolateral convexity of head; mesosoma relatively long and slender; pronotum and mesosoma in lateral view forming a low dome; promesonotal suture completely separating pronotum from mesonotum; mesopleuron defined strongly to faintly from mesonotum by a suture and/or carina, and defined well from metapleuron by a suture and/or carina; metanotal groove shallowly to moderately impressed, or sometimes inconspicuous dorsally; propodeum in lateral view with a relatively long and straight dorsal outline; propodeal spines absent; orifice of propodeal spiracle elliptical to slitlike; propodeal lobe very low or absent; apicoventral part of foretibia with a small simple spur behind a large pectinate spur; apicoventral part of mid and hind tibia with a simple spur in front of a large pectinate spur; anterior peduncle of petiole reduced or absent; petiolar node in lateral view high, tapering to a single spinous dorsal apex; subpetiolar process developed as a lobe; girdling constriction between abdominal segments III and IV indistinct; abdominal sternite III with a distinct anteroventral flange beneath helcium; sting well developed.

Differentiation. The worker of Odontomachus is most similar to that of Anochetus, but in the latter the posterior face of head inside preoccipital carina lacks a pair of dark lines; vertex lacks a median longitudinal carina.

Vietnamese species (6 spp.).

O. silvestri Wheeler, 1927 [senior synonym of O. silvestri substriatus Wheeler, 1927]. Type locality of O. silvestri: Dong Mo [probably in northern Vietnam]; type locality of “ O. silvestri substriatus ”: Tocco [unidentified locality name]. Au (Bac Kan, Ba Vi, Chua Yen Tu, Cuc Phuong, Pu Mat, Sa Pa, Van Ban), Rad (Cuc Phoung).

O. monticola Emery, 1892 . Au (Ba Be, Chua Yen Tu, Tay Yen Tu, Van Ban), Rad (Cuc Phuong).

O. rixosus F. Smith, 1857 . Zry (Cat Tien).

O. simillimus F. Smith, 1858 . Rad (nr. Ha Noi), Zry (Cat Tien).

O. sp. eg-2 [= sp. 13 of SKY in Eguchi, Bui et al. (2005); cf. O. xizangensis Wang, 1993] (Ba Vi, Sa Pa, Tam Dao, Van Ban)

O. sp. eg-4 (Phu Quoc).

Bionomics. Odontomachus spp. usually occur in well-developed forests and other wooded habitats. They nest in rotting logs and wood fragments, and in litter and soil.