Threat Level: Low

Cardiocondyla kagutsuchi is known to occur widely across Asia and the Pacific Islands. Together with its purported sister species, C. mauritanica, this species has often been confused for C. nuda. Accurate identifications of Cardiocondyla species can be difficult because of their small size and similar generalized appearance. Separating C. kagutsuchi from C. mauritanica is especially difficult, and it is presently beyond the scope of PIAkey to distinguish the two species using traditional characters.

Although C. kagutsuchi is more widespread in the Pacific, C. mauritanica is also reported from Indonesia, the Philippines and Papua New Guinea. For a detailed taxonomic treatment of these two species, users are referred to Seifert (2003). If a determination is needed, but the user cannot reliably distinguish the two species from each other, it is recommended to determine the specimens as "Cardiocondyla nr. kagutsuchi", which means it has been determined to be a species near Cardiocondyla kagutsuchi. Users are also cautioned against using the differences observed between the photographs of C. kagutsuchi and C. mauritanica to make a determination, because the colors of the two species can vary.

Other genera appearing in PIAkey with a two segmented waist and three segmented antennal club include Monomorium, Tetramorium and Pheidole. In addition to the characters given in the identification guide and comparison charts, Cardiocondyla can also be separated from the previously mentioned genera by the very swollen appearance of the postpetiole in dorsal view .

Cardiocondyla kagutsuchi and C. mauritanica can usually be distinguished from other introduced Cardiocondyla by the characters illustrated in the comparison chart.

For a detailed taxonomic treatment of the world Cardiocondyla, a recent revision of the genus provided by Seifert (2003) is an excellent resource.

Waist with two segments (petiole & postpetiole)
Propodeal spines present & short
Antennal scrobe absent
Antennal scapes do not exceed posterior margin of head
Antennal club with three segments
Slope of mesosoma gradual, not steep
Metanotum not impressed
Postpetiole appears swollen in dorsal view Posteptiolar anterior corners bluntly rounded Postpetiole with anterior margin weakly concave

Chart 1. Cardiocondyla vs. Mononomorium, Tetramorium, Pheidole.
Chart 2. C. kagutsuchi vs. Cardiocondyla species with impressed metanotum.
Chart 3. C. kagutsuchi vs. Cardiocondyla species without impressed metanotum.

Chart 1. Cardiocondyla vs. Mononomorium, Tetramorium, Pheidole

	Cardiocondyla	Mononomorium	Tetramorium	Pheidole (minor worker)
Face
Profile
Propodeal spines	present	absent	present	present
Mesosoma slope	gradual	gradual	gradual	steep
Antennal scrobes	absent	absent	present	absent
Antennal scapes relative to posterior margin of head	shorter	shorter	shorter	longer
	Cardiocondyla	Mononomorium	Tetramorium	Pheidole (minor worker)

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	C. kagutsuchi	C. emeryi	C. obscurior	C. wroughtonii
Face
Profile
Metanotal impression	absent	present	present	present
Propodeal spines (variable character)	small	long	moderate	long
	C. kagutsuchi	C. emeryi	C. obscurior	C. wroughtonii

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	C. kagutsuchi	C. minutior	C. mauritanica
Face
Profile
Metanotal impression	absent	absent	absent
Propodeal spines (variable character)	small	moderate	small
	C. kagutsuchi	C. minutior	C. mauritanica

• 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.
  
  
• Heinze, J., Cremer, S., Eckl, N. & Schrempf, A. (2006) Stealthy invaders: the biology of Cardiocondyla tramp ants. Insectes Sociaux, 1-7.
  
  
• Seifert, B. (2003) The ant genus Cardiocondyla (Insecta: Hymenoptera: Formicidae) - a taxonomic revision of C. elegans, C. bulgarica, C. batesii, C. nuda, C. shuckardi, C. stambuloffii, C. wroughtonii, C. emeryi, and C. minutior species groups. Annalen des Naturhistorischen Museums in Wien Serie B Botanik und Zoologie, 104B, 203-338.
  
  
• Terayama, M. (1999) Taxonomic studies of the Japanese Formicidae, Part 6. Genus Cardiocondyla Emery. Memoirs of The Myrmecological Society of Japan, 99-107.