Monomorium liliuokalanii

  • Synopsis
  • Diagnostic Characters
  • Comparison Chart
  • Images
  • Video
  • Nomenclature
  • References & Links

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).


  • Waist with two segments (petiole & postpetiole)
  • Propodeal spines absent
  • Antennal club with three segments
  • All body surfaces smooth and shining without sculpture
  • Entirely dark, the only pale portions are the legs and antennae
  • Worker caste monomorphic (all same size)

Chart 1. Monomorium vs. Cardiocondyla, Solenopsis
Chart 2. Monomorium liliuokalanii vs. other Monomorium species


Chart 1. Monomorium vs. Cardiocondyla & Solenopsis

Monomorium Cardiocondyla Solenopsis
Propodeal spines



Number of antennal club segments



Monomorium Cardiocondyla Solenopsis

(top of page)

Chart 2. M. liliuokalanii vs. other Monomorium species
M. liliuokalanii M. floricola M. destructor M. pharaonis
Mesosoma sculpture



absent from propodeum

Pale portions of body


mesosoma & waist

all except gaster

Petiole length relative to height
approximately equal

distinctly greater
not applicable not applicable
M. liliuokalanii M. floricola M. destructor M. pharaonis
All images of M. liliuokalanii that currently appear in PIAkey were photographed by April Nobile and are taken with permission from

No video available is available for this species.

Subfamily Myrmicinae

Monomorium liliuokalanii, together with M. minutum samoanum, were treated as a junior synonyms of M. minutum by Wilson and Taylor (1967). However, the species originally described by Mayr (1855) as M. minutum is native to Mediterranean Europe and has never been implicated in the invasion of Pacific islands. Furthermore, M. minutum Mayr was renamed M. monomorium by Bolton (1987) in order the resolve a taxonomic conflict violating the rules of nomenclature.

Therefore, literature pertaining to Pacific islands ants and specimens collected in the Pacific that use the name M. minutum are most likely referring to the species M. liliuokalanii Forel (1899) and not M. monomorium.

Monomorium liliuokalanii. Monomorium minutum var. liliuokalanii Forel, 1899a: 119 (w.) HAWAII. Subspecies of minutum: Forel, 1909d: 225. Junior synonym of minutum: Wilson & Taylor, 1967: 67. Revived from synonymy, raised to species, and senior synonym of samoanum: Bolton, 1987: 228.

  • Antweb: specimen images, data & maps

  • Bolton, B. (1995) A new general catalogue of the ants of the world. Harvard University Press, Cambridge, Massachusetts, 504 pp.

  • Heterick, B. (2001) Revision of the Australian ants of the genus Monomorium (Hymenoptera: Formicidae)
    Invertebrate Taxonomy, 15, 353-459.

  • Heterick, B. (2006) A revision of the Malagasy ants belonging to genus Monomorium Mayr, 1855 (Hymenoptera: Formicidae). Proceedings of the California Academy of Sciences, 57, 69-202.

  • Wilson, E.O. & Taylor, R.W. (1967) The ants of Polynesia (Hymenoptera: Formicidae). Pacific Insects Monograph, 14, 1-109.