Key to Odontomachus infandus species group

This worker key is based on: Wang, W.Y., Yamada, A., Yamane, S. 2020. Maritime trap-jaw ants (Hymenoptera, Formicidae, Ponerinae) of the Indo-Australian region – redescription of Odontomachus malignus Smith and description of a related new species from Singapore, including first descriptions of males. ZooKeys 915: 137–174 (doi:10.3897/zookeys.915.38968).

Preliminary key to the known species of the sensu Brown (1976), excluding species confined to Lesser Sunda Islands, New Guinea, and Fiji, based on the worker caste. (Undescribed species are omitted; see also Sorger and Zettel (2011) and General (2018) for Philippine species.)

1

Vertex posteriorly with protuberance on each side of median furrow. Meso-pleuron with anteroventral margin that is strongly developed and looks like a tubercle when seen in dorsal view O. malignus . . . . . 2
Vertex without such protuberance. Anteroventral margin of mesopleuron less developed, not like tubercle when seen in dorsal view. . . . . 3

2

return to couplet #1

Propodeal junction strongly angulate, with dorsum separated from declivity by strong transverse carina. Mesosoma uniformly dark reddish brown. Body sculpture stronger; lateral face of pronotum coarser than that on dorsal face and less shiny. [Singapore, Borneo] . . . . . Odontomachus litoralis

Propodeal junction rounded, with more weakly carinate edge. Pronotum paler than rest of mesosoma. Body sculpture weaker; sculpture on lateral face of pronotum similar to or weaker than that on dorsal face, and interspaces mostly smooth and shiny. [Singapore, Borneo, Lesser Sundas to Oceania] . . . . . Odontomachus malignus

3

return to couplet #1

First gastral tergite entirely micropunctate, covered with dense, short ap-pressed hairs, without flattened area and pit. Dorsum of head and almost entire mesosoma with dense erect or suberect hairs that are very short and of almost same length. Pronotal dorsum without long erect hairs. [Vietnam] . . . . . Odontomachus silvestrii

First gastral tergite essentially smooth and shiny (punctation, if any, very faint and sparse), anteriorly extensively flattened and often with pit corresponding to petiolar spine. Condition of short hairs on head and mesosoma variable, but hairs may be longer, appressed, curved, or much sparser depending on species. Pronotal dorsum occasionally with one or two pairs of long hairs. O. infandus group (s. str.) . . . . . 4

4

return to couplet #3

Head orange-yellow to yellowish brown contrasting with dark brown to blackish mesosoma . . . . . 5
Body generally concolourous, but sometimes head, especially lateral faces, lighter than rest of body . . . . . 6

5

return to couplet #4

Gaster dark brown. Mesosoma with dense decumbent to appressed hairs that are relatively long (generally much longer than space between hairs). Anterior face of petiole with similar hairs that are often suberect. Dorsum of head posteriorly with superficial sculpture and somewhat shiny. Lateral face and basal part of anterior face of petiole with distinct striae . . . . . Odontomachus banksi

Gaster light brown, similar to head in coloration. Hairs on mesosoma shorter (generally as long as or shorter than space between hairs). Hairs on anterior face of petiole very fine, appressed and less conspicuous. Dorsum of head posteriorly distinctly striate and matte. Petiole almost entirely smooth . . . . . Odontomachus alius

6

return to couplet #4

Dorsum of head behind ocular prominence entirely sculptured and matte. Mesopleuron entirely striate . . . . . 7
Dorsum of head behind ocular prominence essentially smooth or very faintly sculptured and shiny. Mesopleuron extensively smooth and shiny . . . . . 8

7

return to couplet #6

Striae on pronotal dorsum essentially longitudinal, rarely weakly concentric. Petiolar spine curved backward in lateral view. . . . . Odontomachus infandus

Striae on pronotal dorsum more distinctly transverse. Petiolar spine almost straight in lateral view. . . . . Odontomachus schoedli

8

return to couplet #6

Body orangish light brown. Pronotal dorsum predominantly with regular transverse striae. . . . . Odontomachus ferminae

Body reddish brown to dark brown. Pronotal dorsum in posterior 2/3 largely with longitudinal striae . . . . . 9

9

return to couplet #8

With petiole in dorsal view spiracle distinctly protruding laterad. Entire extraocular furrow essentially smooth with very sparse minute punctures. With mesosoma in profile, dorsal outline weakly and broadly concave. . . . . Odontomachus scifictus

With petiole in dorsal view spiracle not protruding laterad. Extraocular furrow predominantly smooth but with superficial striae at least partly. With meso-soma in profile, dorsal outline more straight. . . . . Odontomachus philippinus