Oligomyrmex is one of the smallest of ants in terms of size both body mass and total length. Workers of these species are typically around 1 millimeter in length. The workers are mostly (as part of Carebara genus) dimorphic with a major worker caste. Being so tiny they are hardly ever spotted even though they are quite common in this locale being found throughout Malaysia. When I was a young boy I thought that these were a species of Pheidole as some species do look strikingly like Pheidole especially considering they are so tiny that unless equipped with a powerful magnifying glass (lens) their features are not easily discernible. Alternate name for this genus is Carebara. Many species of Oligomyrmex are specialist thief ants but not all.
Sp1.
The major worker of Oligomyrmex sp1. This is the smallest species of Oligomyrmex in terms of length in this post. This species is not a specialist thief ant.
Workers of Oligomyrmex against a millimeter tape. The minor worker of this first species is slightly below 1 millimeter while the major is around 1.5 millimeter.
The major and minor (turned turtle) worker of Oligomyrmex.
The major worker of Oligomyrmex sp1.
The major worker of Oligomyrmex sp1.
Sp2.
The major worker of a glossy looking Oligomyrmex species. This species has a glossy appearance. It also has the longish appearance as compared with the first species. This species is not a specialist thief ant.
The minor worker of Oligomyrmex sp. The minor worker at 1 mm.
The major and minor workers of Oligomyrmex sp.
The minor worker of Oligomyrmex sp. The minor worker at 1 mm.
A female alate of Oligomyrmex.
Major and minor workers of Oligomyrmex.
A major worker of Oligomyrmex carrying a pupa.
Major and minor workers of Oligomyrmex.
Sp3.
A major worker. This third species is similar to the second with the same longish apperance but it is not glossy in appearance. This is a specialist thief ant species.
The major worker of Oligomyrmex sp3 showing the 'horns' at the back of the head.
The major worker of Oligomyrmex sp3 showing the 'horns' at the back of the head.
The gyne or queen of Oligomyrmex sp3 surrounded by her protective workers.
Major and minor workers of Oligomyrmex sp3. The 'horns' at the back of the head of the major is here (top and bottom image) bearly visible.
Major and minor workers of Oligomyrmex sp3. The 'horns' at the back of the head of the major is here (top and bottom image) barely visible.
Oligomyrmex queen surrounded by her protective workers.
Minor workers of this Oligomyrmex species feeding on part of a dragon fly. Major workers of thief ants specialist Oligomyrmex species do not commonly take part in food acquisition.
The queen of Oligomyrmex.
Female alate of Oligomyrmex sp. in the ready for mating position.
Male alate of Oligomyrmex sp.
Males of Oligomyrmex come in two forms, one form (above) more similar to males of Myrmiciane ants and most Ponerinae ants and another form similar to the less typical ants such as Diacamma genus and Odontomachus rixosus (but not Odontomachus simillimus ).
Sp5.
Here is a ‘long form’ Oligomyrmex species. The gaster of the minor workers are longer and pointed at the end. This is another thief ant species.
The major worker and minor worker of this longish Oligomyrmex species. Barely visible in this photo is the horns on the back of the head of the major worker.
The major worker and minor worker of this longish Oligomyrmex species
A female alate of this 'long form' Oligomyrmex ant.
Sp4.
Here is a large species of Oligomyrmex also a ‘long form’ species. The major worker at 4.5 millimeters is huge compared with the minor worker at just below 2 millimeters. This is another thief ant species.
Major and minor workers of a 'large' Oligomyrmex species.
Major worker of this 'large' Oligomyrmex species showing the horns on the back of its head.
One of the larger Oligomyrmex ant, the minor worker is almost 2 millimeters.
The male of this 'large' Oligomyrmex species.
Sp6.
Minor, major workers and female alates of Oligomyrmex sp. This species resembles sp3 (above) but the major workers do not have horns at the back of their heads.
Minor, major workers and female alates of Oligomyrmex sp.
Minor, major workers and female alates of Oligomyrmex sp.
Carebara
Workers of Carebara sp.
Worker of Carebara sp(01). This species has queens and males that are large around the size of those of Pheidologeton affinis.
Workers of monomorphic Carebara sp(02) ants. This is the more typical small species with workers just slightly over 1 millimeter in total length (TL).
Taxonomy:
Kingdom - Animalia
Phylum - ArthropodaSubphylum - Hexapoda
Class - Insecta
Subclass - Pterygota
Infraclass - Neoptera
Order - Hymenoptera 7399
Suborder - Apocrita 7400
Infraorder - Aculeata 7434
Superfamily - Vespoidea 34725
Family - Formicidae 36668
Subfamily - Myrmicinae 34685
Tribe: Pheidologetonini 144016
Genus: Carebara 369107 / Oligomyrmex 369190
Last Updated: 2014 08 21
First Posted: 2011 11 11
© 2011 - 2014 Quah. All rights reserved.
I have always found that the easiest way to identify Oligomyrmex from Pheidole is by the large thorax of majors in Oligomyrmex. Hope this helps.
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