The Ants of Africa
SUBFAMILY MYRMICINAE - Genus Oligomyrmex
Contents - Myrmicinae - Carebara sensu Fernandez - Introduction

Genus Oligomyrmex Mayr (1867a: 110)

In Tribe PHEIDOLOGETONINI. Genus in need of revision, although some examination was made by Ettershank (1966).

Diagnostic Features - Dimorphic, major workers with massive heads. Median portion of clypeus longitudinally bicarinate. Antennae 9-, 10- or 11-segmented, with a 2-segmented club. Eyes present but small. Promesonotal suture absent, metanotal groove impressed. Propodeum armed with a pair of teeth or at least sharply angulate. Yellow to deep brown.


Now [November 2007] regarded by FernŠndez (2004) as in the genus Carebara {original description}.


African subgenera Aeromyrma Forel (1891b: 198; subgenus status by Emery, 1915c: 59); Aneleus Emery (1900c: 327 as subgenus of Pheidologeton; raised to genus by Emery, 1914a: 41; senior synonymy of Sporocleptes, by Consani,1951: 169); Crateropsis (Patrizi, 1948: 174); and, Nimbamyrma (Bernard, 1953b: 240).

Mayr's (1867a) genus definition and description of the type specimen, a queen of O. concinnus, with 9-segmented antennae, is at {original description}; the workers and male remain unknown.  He likened the general form of the queen to that of a Solenopsis, i.e. with a rectangular or sub-rectangular head in full face view [S. fugax was well known to him; S. geminata & S. molesta also were known at that time], and gave the size as TL 4 mm
Forel's (1891b) definition of Aeromyrma, with 11-segmented antennae, is at {original description} and {original description}. Emery's (1900c) definition of Aneleus, with 11-segmented antennae, is at {original description}. Patrizi's (1948) definition of Crateropsis is at {original description}. Bernard's (1952) definition of Nimbamyrma is at {original description}.

Bolton (1995) did not maintain any subgenera, attributing synonymisation to Ettershank (1966). The latter described examining Malpighian tubules from three undetermined species from Ivory Coast and synonymised several former genera. However, he appears to have felt separation into subgenera on the basis of the number of antennal segments might be justified; thus Aneleus has 11-joints, Aeromyrma has 10; Oligomyrmex has 9; and Octella has 8.

According to Ettershank's review (1966) colonies are generally rather small, or broken up into small subcolonies. Collections usually come from under the bark of logs, in rotten wood, in leaf litter, or in other generally humid places. Most may be lestobiotic, probably feeding on arthropod eggs. There is no modern taxonomic revision.

Bernard (1952) not only maintained the early genera but defined a new genus Nimbamyrma. From his notes, six species of Aneleus were known but only one was taken at Mt. Nimba, Guinea, silvestrii of which he was able to describe the male, a first for the genus (see below). From Aeromyrma he wrote of 3 isolated females, each of a distinct species, taken by Lamotte at Nion (700 m), Ravine I of Mount TŰ (forest). The revision by Weber (1950) had been limited by the major caste being the only well known morph. However Bernard, who described the first male of the then genus Aneleus (silvestrii, see below) noted that the male morphology suggested Aneleus might be no more than a subgenus of Oligomyrmex; although the major and minor workers had 11-segmented antennae compared to the 10-segmented antennae of Oligomyrmex. In a footnote, Bernard added that an important collection of subterranean ants, by A. Machado, had just been received by him from Angola, and that included numerous workers of Nimbamyrma.

The synonymy of Nimbamyrma (villiersi) with Oligomyrmex by Ettershank seems questionable. Bolton (1973) who refers to Ettershank, has Oligomyrmex with the clypeus bicarinate and the propodeum with a pair of teeth or at least sharply angulate. Bernard (1952) wrote of (translated) "the clypeus without carina", the propodeum has two pairs of spines, as often seen in Tetramorium species, and (perhaps by default) there is no knowledge of dimorphism in Nimbamyrma. Similarly Wheeler (1922) listing features of Aeromyrma noted clypeus without carina.

My feeling is that the distinctive species, O. (Aneleus) politus (Santschi), which appears to have only a minor worker and not a major, perhaps merits elevation to monotypic Genus status see Oligomyrmex politus for details and the synonymy of villiersi. The revisionary paper by FernŠndez (2004) resolves this by placing all in Carebara, although he did not consider the likely synonymy of Nimbamyrma villiersi under O. politus.

Santschi's (1913e) early key is at {original description} - NOTE infimus now is in the genus Paedalgus, and antennal counts are not used. Weber's (1952) key to Aeromyrma is at {original description}. He also provided notes on the biology of the genus, these are at {original description}.


Key to major workers : Key to minor workers : Key to global Oligomyrmex


Species from West Africa listed only by code letters

Oligomyrmex species I

Listed by Room (1971) from leaf litter under cocoa and bananas at the Mampong Cemetery farm in Ghana.


Oligomyrmex species A176

Listed by Room (1971) from soil in all parts of the Mampong Cemetery farm in Ghana.


Oligomyrmex species A179

Listed by Room (1971) from cocoa leaf litter and soil under Euphorbia at the Mampong Cemetery farm in Ghana.


Oligomyrmex species (indet.) (1)

Described as widespread in Ghana, by Belshaw & Bolton (1994b), who found 447 workers in leaf litter and 7 in soil samples at 10 locations in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (2)

Described as widespread in Ghana, by Belshaw & Bolton (1994b), who found 1957 workers in leaf litter and 333 in soil samples at 15 locations in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (3)

Described as widespread in Ghana, by Belshaw & Bolton (1994b), who found 1532 workers in leaf litter and 175 in soil samples at 12 locations in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (4)

Found in Ghana, by Belshaw & Bolton (1994b), who collected 123 workers in leaf litter and soil samples at 6 locations in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (5)

Described as widespread in Ghana, by Belshaw & Bolton (1994b), who found 245 workers in leaf litter samples at 6 locations in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (6)

Described as widespread in Ghana, by Belshaw & Bolton (1994b), who found 967 workers in leaf litter and 81 in soil samples at 13 locations in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (7)

Found in Ghana, by Belshaw & Bolton (1994b), who collected 6 workers in leaf litter and 92 in soil samples at Bunso in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (8)

Described as widespread in Ghana, by Belshaw & Bolton (1994b), who found 602 workers in leaf litter samples at 6 locations in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (9)

Found in Ghana, by Belshaw and Bolton (1994b), who collected 122 workers in leaf litter and 34 in soil samples under forest at Bunso and Atewa Forest Reserve in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (10)

Found in Ghana, by Belshaw and Bolton (1994b), who collected 197 workers in leaf litter samples under primary forest at Jachie, Juaso and Esukawkaw Forest Reserve in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (11)

Found in Ghana, by Belshaw & Bolton (1994b), who collected 12 workers in leaf litter and 27 in soil samples under cocoa at Effiduase in the semi-deciduous forest zone.


Oligomyrmex species (indet.) (12)

Found in Ghana, by Belshaw & Bolton (1994b), who collected 104 workers in leaf litter samples from primary and secondary forest at Kade and Bunso in the semi-deciduous forest zone.


Oligomyrmex species

In Ghana, 18 workers were collected from the ground at CRIG by Bigger (1981a)

Contents MYRMICINAE Introduction
© 2007, 2008, 2010 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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