Threat Level: Low

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.

Solenopsis and Cardiocondyla are often confused with Monomorium. Monomorium and Solenopsis lack propodeal spines and are often lightly sculptured or smooth. Solenopsis papuana and its minute, small-eyed relatives are easily mistaken for Monomorium. However, the antennal club of Monomorium is three or more segments, and that of Solenopsis is two segments.

Cardiocondyla also has a three-segmented antennal club, but the presence of propodeal spines (occasionally very small) and a swollen postpetiole (in dorsal view) can help separate it from Monomorium.

Monomorium floricola is the PIAkey species most closely resembling M. liliuokalanii. They are equivalent in size, shape and glassy sculpture. Wilson and Taylor (1967) separate the two species by the length of the petiolar peduncle relative to petiolar node. Although the middle portions of M. floricola are often a shade of red, specimens can also approach the more uniform black of Monomorium liliuokalanii.

There are many species of Monomorium that have spread across the Pacific Islands that are not included in the current version of PIAkey, including M. latinode, M. sechellense and species belonging to the M. salomonis group. Images of all these species are available at Antweb. Recent taxonomic revisions of the Australian and Malagasy Monomorium are also available (Heterick 2001, 2006).

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