Monomorium liliuokalanii
Monomorium liliuokalanii is a minute, dark colored species with a glassy smooth surface free of punctate sculpture. This species has mistakenly been referred to as M. minutum in the literature, and perhaps in collections (see nomenclature section for more details). Little is known about the effect this species has on native diversity, agriculture or human health, but it is not believed to be a particularly destructive ant.
Diagnosis of worker among Antkey species. Worker caste monomorphic. Head shape ovoid. Antenna 12-segmented. Antennal club 3-segmented. Antennal scrobe lacking. Antennal insertions at least partly covered by frontal lobes; not surrounded by a raised sharp-edged ridge. Frontal lobes do not obscure face outline between mandible and eye Antennal scapes not conspicuously short; easily extended beyond eye level. Posterolateral corners of head unarmed, without spines. Eyes medium to large (greater than 6 facets); distinctly less than half head length. Mandibles triangular. Mesosoma with erect hairs; shining smooth lacking any areas covered with punctate sculpture. Pronotal spines absent. Propodeum lacking spines or teeth. Waist 2-segmented. Petiole with peduncle; lacking large subpetiolar process. Petiole length approximately equal to petiole height, but never distinctly greater. Postpetiole not swollen, in dorsal view not distinctly broader than long or distinctly wider than petiole. Color shiny dark brown to black.
Among introduced and commonly intercepted Monomorium, M. liliuokulanii can be distinguished from M. destructor, M. pharaonis and the M. salomonis group by its glassy smooth integument that lacks sculpture even on the mesosoma. Among smooth and shining Monomorium, M. liliuokulanii is distinguished from M. ebeninum (which is also uniformly dark) and M. floricola (which is bicolored) by the petiole shape which is approximately as long as tall in profile view, and never distinctly longer than tall in profile.