Tetramorium obtusidens

Bolton, B., 1979, The ant tribe Tetramoriini (Hymenoptera: Formicidae). The genus Tetramorium Mayr in the Malagasy region and in the New World., Bulletin of the British Museum (Natural History) Entomology 38, pp. 129-181 : 177

The obtusidens -complex

In the previous part of this study (Bolton, 1977: 101) a number of samples were treated under the name T. obtusidens Viehmeyer , and I said at the time that, ' I suspect that the name obtusidens may conceal more than one valid species'. Now I am of the opinion that three separate species exist in this complex of the bicarinatum-group. They are characterized within the group by their small size (HW <0.65, SL <0.55), smooth unsculptured mandibles, pale yellow colouring and vestigial or absent basigastral sculpture. All three will run out to obtusidens in the 1977 key but may be separated as follows.

a Alitrunk in dorsal view with a strong transverse carina at the pro-mesonotal junction. Postpetiole dorsum with strong rugulose sculpture. (Thailand, Borneo) ... adelphon (p. 177)

- Alitrunk in dorsal view without a transverse carina at the pro-mesonotal junction. Postpetiole dorsum punctulate or with 1 - 2 very faint rugulae ........ b

b Hairs on dorsal alitrunk abundant, fine, curved or sinuate. Smaller species, HW <0.55. (Singapore) ........... obtusidens (p. 178)

- Hairs on dorsal alitrunk sparse, stout, more or less straight and blunted apically. Larger species, HW> 0.55. (New Guinea) ....... kydelphon (p. 177)