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Abstract: By combining morphological and molecular analyses we scrutinize the taxonomic status of selected ant species of the Tetramorium bicarinatum (Nylander, 1846) species group. We confirm Apomyrmex manobo Calilung, 2000 as a member of the genus Tetramorium, and evaluate whether T. manobo and T. scabrum Mayr, 1879, which currently is a junior synonym of T. pacificum Mayr, 1870, are specifically distinct from T. pacificum. Morphometry shows clear differences between workers of the three ants. Sequence comparison of 700 bp of the mitochondrial COI gene confirms that they constitute separate species, embedded in the T. bicarinatum species group. Thus, we confirm T. manobo as a valid species and revive T. scabrum sp.rev. from synonymy. Pronounced morphological variation between T. scabrum populations indicates the possible existence of more than one species. We discuss our findings in terms of plesiomorphy and / or convergent evolution of worker morphology. Tetramorium manobo appears to be a Philippine endemic restricted to the subregion "Greater Mindanao", where it inhabits forest habitats. In contrast, on the Philippines T. pacificum is found only in disturbed habitats. Additionally, we review the ants of the T. bicarinatum group currently known from the Philippines and add the first record of T. obtusidens Viehmeyer, 1916.