Odontomachus

Sorger, D. M. & Zettel, H., 2011, On the ants (Hymenoptera: Formicidae) of the Philippine Islands: V. The genus Odontomachus Latreille, 1804., Myrmecological News 14, pp. 141-163 : 143-146

Key to Philippine species of Odontomachus (workers)

1 Subapical tooth of mandible truncate (Figs. 40, 43).. ........................................................................ 2

- Subapical tooth of mandible acute (or very narrowly rounded if worn) (Figs. 3 - 8, 21, 24, 37).. ..... 3

2 Subapical tooth and apex of mandible very short, blunt. Body dark brown. Temporal prominences striate. Striation on pronotum predominantly concentrical. Gaster tergite 2 anteriorly with fine microsculpture. ( O. haematodus species group) (Figs. 43 - 45) ................ Odontomachus simillimus

- Subapical tooth and apex of mandible elongate. Head and gaster light brown. Temporal prominences smooth. Striation on pronotum predominantly transverse. Gaster tergite 2 anteriorly smooth. ( O. rixosus species group) (Figs. 40 - 42) ...................................... Odontomachus rixosus

3 Head posteriorly with pair of small, but distinct tubercles. Pronotum granulate, at most with very superficial striation. SI = 1.2 - 1.3. In lateral view, anterior face of gaster tergite 1 evenly convex, without impression at position of apex of petiolar spine. ( O. malignus species group) (Figs. 37 - 39) ................................. Odontomachus malignus

- Head posteriorly without tubercles (Figs. 3 - 8). Pronotum with distinct striation of variable directions. SI> 1.35 (except in one species from Mindanao SI = 1.2). In lateral view, anterior face of gaster tergite 1 flattened (Figs. 22, 25, 27, 33, 35), with small impression (pit or line) at position of apex of petiolar spine (rare individual exceptions for both characters do occur). ( O. infandus species group) .................................... 4

4 Posterior dorsum of head mainly punctured, some faint striation near extraocular furrow often present (Figs. 6 - 8, 24).. .............................................. 5

- Posterior dorsum of head mainly striate, a very small smooth area posteriorly near median furrow common (Figs. 3 - 5, 9).. ................................. 8

5 SI = 1.2. Anterior part of tergite 1 almost evenly rounded. Pronotum postero-medially with longitudinal striation, horseshoe-shaped. Species of Mindanao. (Figs. 24 - 26) ........ Odontomachus sp. 2

- SI> 1.35. Anterior part of tergite 1 distinctly flattened. Pronotum with different striation. (Figs. 18 - 20) ................................................................... 6

6 Head yellowish orange. Mesopleuron completely striate. Mesosoma with dense pilosity. Species of southern Luzon. (Figs. 8, 14, 20) .................. .............................................. Odontomachus banksi

- Head dark brown. Centre of mesopleuron largely smooth. Mesosoma with sparse pilosity (Figs. 6, 7, 12 - 13).. ............................................................. 7

7 Smooth area on mesopleuron reaching meso-metapleural suture. Petiole widest at distinct anterior tubercles (width of node equal or smaller than width at tubercles). Species from Camiguin. (Figs. 7, 13, 19) ....... Odontomachus scifictus sp.n.

- Mesopleuron with stripe of short striae along meso-metapleural suture. Petiole with weak tubercles, at node wider than at tubercles. Species from the Western Visayas (Negros, Panay, Siquijor). (Figs. 6, 12, 18) .... Odontomachus philippinus

8 Head and mesosoma unicolourous reddish brown. Petiole stout, with almost straight spine. Species from the mountains of northern Luzon. (Figs. 4, 10, 16) ..................... Odontomachus schoedli sp.n.

- Head distinctly lighter than mesosoma (exceptions in O. infandus only occur, if both parts are very dark brown). Petiole less stout. (Figs. 3, 5, 9, 11, 21, 22) .............................................................. 9

9 Gaster tergites 1 and 2 partly yellowish brown, tergite 1 anteriorly low, strongly flattened; impression, if pit-shaped, at or behind mid-length. Petiole with very elongate spine. Striation of pronotum variable (transverse or longitudinal). Species from the central and eastern Philippines (absent from Luzon and Mindoro). (Figs. 5, 12, 17).. ....................................... Odontomachus alius sp.n.

- Gaster tergites 1 and 2 dark (blackish) brown, tergite 1 anteriorly comparatively high; impression, if pit-shaped, before mid-length (Fig. 22). Petiolar spine shorter (Figs. 9, 22). Striation of pronotum longitudinal, usually in loops (Figs. 15, 23).. ...................................................................... 10

10 Striation of head almost complete. Head usually light to dark brown. Petiolar spine curved. Species widely distributed on Luzon and Mindoro. (Figs. 3, 9, 15) .................... Odontomachus infandus

- Striation of head posteriorly reduced. Head yellowish orange, strongly contrasting with mesosoma. Petiolar spine straight. Species from southern Luzon. (Figs. 21 - 23) ....... Odontomachus sp. 1