Threat Level: Low

Cardiocondyla obscurior is introduced throughout the Pacific Island region, but its effects on native biodiversity, agriculture and human health appear to be very limited. Accurate identifications of Cardiocondyla species can be difficult because of their small size and similar generalized appearance.

Other genera appearing in PIAkey with a two segmented waist and three segmented antennal clubs 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 obscurior can usually be distinguished from other introduced Cardiocondyla by the combination of the following characters: (1) the metanotum is impressed, (2) the anterior corners of the posteptiolar node are sharply angled causing the posteptiolar anterior margin to appear strongly concave, (3) the entire gaster is uniformly darker than the rest of the body. Although the gaster of C. wroughtonii is almost always the same pale color as the rest of its body, there are populations reported from the Philippines and Malaysia in which first gastral tergite is occupied by a large brown spot that is centrally notched on its hind margin. Cardiocondyla obscurior can be separated from these "dark morph" C. wroughtonii because the gaster of the former is uniformly darker than the rest of its body, while that of the latter is only partially darker than the rest of its body. Additionally, the spines of Cardiocondyla obscurior tend to be shorter than those of C. wroughtonii.

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

Chart 1. Cardiocondyla vs. Mononomorium, Tetramorium, Pheidole
Chart 2. Cardiocondyla obscurior vs. Cardiocondyla species with impressed metanotum.
Chart 3. Cardiocondyla obscurior 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. obscurior	C. emeryi	C. wroughtonii
Face
Profile
Metanotal impression	present	present	present
Postpetiole in dorsal view	anterior corners sharp; anterior margin strongly indented	anterior corners blunt; anterior margin weakly indented	anterior corners sharp; anterior margin strongly indented
Propodeal spines (variable character)	moderate	long	long
Color of gaster relative to body (variable character)	uniformly darker	uniformly darker	same, or only darker on portion of 1st gastral tergite
	C. obscurior	C. emeryi	C. wroughtonii

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	C. obscurior	C. minutior	C. kagutsuchi	C. mauritanica
Face
Profile
Metanotal impression	present	absent	absent	absent
Propodeal spines	moderate	moderate	small	small
	C. obscurior	C. minutior	C. kagutsuchi	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.