Key to Afrotropical Centromyrmex species

The genus Centromyrmex occurs in three regions and includes 15 species and 2 subspecies. These can conveniently be separated into four species groups. The keys below include a key to the species groups, a key to the Afrotropical species and a key to the Neotropical species. The species groups and Afrotropical key were originally published here:

Bolton, B. and B. L. Fisher. 2008. Afrotropical ants of the ponerine genera Centromyrmex Mayr, Promyopias Santschi gen. rev. and Feroponera gen. n., with a revised key to genera of African Ponerinae (Hymenoptera: Formicidae). Zootaxa 1929: 1-37. [[Media:Bolton & Fisher 2008.pdf|PDF]]

and the Neotropical key was published by Kempf:

Kempf, W.W. 1967. A synopsis of the Neotropical ants of the genus Centromyrmex Mayr (Hymenoptera: Formicidae). Stud. Entomol. 9: 401-410.

Species group key

Afrotropical species key

Neotropical species key

1

 * Mesotibia with 1 or 2 spurs. Procoxa not hypertrophied. Protibia not inflated. Pronotum not marginate anterodorsally . . . . . 2


 * Mesotibia without spurs. Procoxa hypertrophied. Protibia inflated. Pronotum marginate anterodorsally. (Afrotropical, Oriental, Malesian . . . . . feae species group

2

 * Mesotibia with 1 spur. Propodeal spiracle not high on side, not very close to dorsal margin of mesosoma. Apical tooth of mandible weakly or not differentiated, not inflected but more or less continuing the line of the long axis of the mandible. Monomorphic species . . . . . 3


 * Mesotibia with 2 spurs. Propodeal spiracle high on side, very close to dorsal margin of mesosoma. Apical tooth of mandible strongly differentiated and inflected, not continuing the line of the long axis of the mandible. Polymorphic species. (Afrotropical) . . . . bequaerti species group

3

 * Ventral process of petiole consisting of two stout teeth. Metasternal process a pair of elongate, narrowly triangular spines. Mesotibial spur pectinate. (Malesian) . . . . . . hamulatus species group


 * Ventral process of petiole consisting of a single keel. Metasternal process a pair of low rounded tumuli or low triangular crests. Mesotibial spur simple to weakly barbulate. (Neotropical) . . . . . . brachycola species group

Key to Afrotropical species (workers)
NOTE. The few known queens will also run in this key, except characters relating to shape of mesosoma in workers do not apply to queens.

A1

 * Mesotibia with two spurs. Metatibia with two spurs, the anterior spur smaller and simple, the posterior spur larger and pectinate. Propodeal spiracle high on side, close to dorsal outline and at about the midlength of the sclerite. Pronotum not marginate anterodorsally. In profile the propodeal dorsum continues the line of the mesonotal dorsum. Subpetiolar process large, keel-shaped. Metasternal process bispinose. Polymorphic species. (bequaerti group) . . . . . 2


 * Mesotibia without spurs. Metatibia with a single large pectinate spur only. Propodeal spiracle low on side, far from dorsal outline. Pronotum marginate anterodorsally. In profile the propodeal dorsum slopes steeply down from the line of the mesonotal dorsum. Subpetiolar process a short slender spine or small triangular tooth. Metasternal process not bispinose. Monomorphic species. (feae group) . . . . . 3

A2

 * With mesosoma in profile the bulla of the metapleural gland is short and does not extend to near the base of the propodeal spiracle. Metatibia with spiniform setae such as are seen on the mesotibia. Protibia ventrally with a single stout spiniform seta, similar to those on the mesotibia, located close to the apex on its outer surface, anterior to and opposite the large spur. (Cameroun, Gabon, Central African Republic, Democratic Republic of Congo, Angola, Malawi, Zambia, Zimbabwe) . . . . . Centromyrmex bequaerti


 * With mesosoma in profile the bulla of the metapleural gland is long and extends to, or even touches, the base of the propodeal spiracle. Metatibia without spiniform setae such as are seen on the mesotibia. Protibia ventrally without a stout spiniform seta that is similar to those on the mesotibia, at most a simple slender seta located close to the apex on its outer surface, anterior to and opposite the large spur. (Gabon) . . . . . Centromyrmex secutor

A3

 * Petiole node in dorsal view conspicuously broader than long . . . . . 4


 * Petiole node in dorsal view at least as long as broad, usually distinctly longer than broad . . . . . 9

A4

 * Apical third of metatibia with a total of more than 3 thickly spiniform setae that arise from its anterior surface opposite the pectinate spur; one or more thickly spiniform setae also arise from the dorsal (outer) surface of the metatibia in the apical third of its length . . . . . 5


 * Apical third of metatibia with only 1–2 (extremely rarely 3) thickly spiniform setae that arise from the apex of its anterior surface, opposite the pectinate spur; no thickly spiniform setae arise from the dorsal (outer) surface of the metatibia in the apical third of its length. . . . . . 6

A5

 * Mandible with 5–6 main teeth that are separated by diastemata, the latter are unarmed or have indistinct low crenulations present. With base of gaster in absolute profile the prora is visible as a distinct raised cuticular crest that extends from the base of the helcium onto the anteroventral surface of the first gastral sternite. Smaller species with narrower head and shorter mandibles, HW 1.20–1.34, PW 0.94–1.12, CI 102–105, MI 71–75. (Cameroun, Gabon, Democratic Republic of Congo) . . . . . Centromyrmex decessor


 * Mandible serially dentate, with 10–12 teeth; all teeth are similar in size and without diastemata separating them. With base of gaster in absolute profile the prora is undeveloped, lacking a raised cuticular crest that extends from the base of the helcium onto the anteroventral surface of the first gastral sternite. Larger species with much broader head and longer mandibles, HW 1.92-2.02, PW 1.50-1.62, CI 119-123, MI 82-84. (Zambia, Zimbabwe) . . . . . Centromyrmex raptor

A6

 * Anterior apex of metatibia with a single thickly spiniform seta, approximately opposite the pectinate spur. (Liberia, Ivory Coast, Ghana, Cameroun, Gabon, Central African Republic, Democratic Republic of Congo, Angola) . . . . . Centromyrmex angolensis


 * Anterior apex of metatibia with two thickly spiniform setae, approximately opposite the pectinate spur . . . . . 7

A7

 * CI 108–118; at low magnification and in full-face view the head capsule appears conspicuously broader than long. Mandibles relatively slightly longer, MI 68–75. Larger species, HW 0.90–1.13. (Guinea, Ivory Coast, Ghana, Nigeria, Cameroun, Gabon, Democratic Republic of Congo, Uganda, Kenya, Zambia, Mozambique, Zimbabwe) . . . . . Centromyrmex sellaris


 * CI 98–101; at low magnification and in full-face view the head capsule appears slightly longer than broad or about as long as broad. Mandibles relatively slightly shorter, MI 59-64. Smaller species, HW 0.65-0.81 . . . . . 8

A8

 * With mesosoma in profile the slope of the anterior portion of the propodeum is steep and slopes abruptly from the mesonotum. Smaller species, HW 0.65-0.68, WL 1.06-1.14. (Cameroun, Gabon) . . . . . Centromyrmex longiventris


 * With mesosoma in profile the slope of the anterior portion of the propodeum is shallow and slopes only weakly from the mesonotum. Larger species, HW 0.79-0.81, WL 1.31*1.34. (Gabon, Central African Republic, Democratic Republic of Congo) . . . . . Centromyrmex ereptor

A9

 * Basal margin of mandible, from basal tooth to basalmost curve, shallowly convex; basal margin much shorter than masticatory margin. Larger species, HL 1.06, HW 0.99, PW 0.82. (Democratic Republic of Congo) . . . . . Centromyrmex praedator


 * Basal margin of mandible, from basal tooth to basalmost curve, shallowly concave; basal margin almost equal in length to masticatory margin. Smaller species, HL < 0.90, HW < 0.85, PW < 0.70. (Democratic Republic of Congo, South Africa) . . . . . Centromyrmex fugator

N1

 * Petiole scarcely longer than broad, the anterior face of node oblique, the dorsal face completely rounded in profile; clypeus with a prominent tumulus on disc . . . . . Centromyrmex alfaroi


 * Petiole distinctly longer than broad, anterior face of node perpendicular to elongate and straight dorsal face; clypeus without a tumulus on disc . . . . . N2

N2

 * Smaller species, thorax length not over 2 mm; mandibles minutely to indistinctly denticulate, chewing border forming almost a right angle with basal border; petiole with a short and pointed subpetiolar process . . . . . Centromyrmex brachycola


 * Larger species, thorax length well over 2.5 mm; mandibles distinctly dentate on basal third, chewing border forming a very. obtuse angle with basal border; petiole with a prominent apically rounded to subtruncate subpetiolar process . . . . . Centromyrmex gigas