The Ants of Africa
SUBFAMILY MYRMICINAE - Genus Oligomyrmex
Key to major workers
Contents - Myrmicinae - MYRMICINAE Introduction

Main Genus page

Key to major or soldier morph (CI and SI mostly derived from the original illustrations)

0 Oligomyrmex elemnteitaeQueen only known; subgenus Crateropsis, head with unique sculptured dorsal concavity Kenya - elmenteitae
-- Antennae 9-segmented subgenus Oligomyrmex
-- Antennae 10-segmented (note - debilis (?) sometimes 9-segmented) subgenus Aeromyrma
-- Antennae 11-segmented subgenus Aneleus
-- subgenus Oligomyrmex --
1 Occiput with at least a lateral tranverse carina, variably produced into a tooth at the angles 2
-- Occiput without a transverse carina, lateral angles rounded without any raised points or teeth 6
2 Oligomyrmex rhodesianus TL ca 2.4 mm, HL 0.71, HW 0.59, SL 0.26, PW 0.40; CI 83, SI 44. rhodesianus
-- TL maximum 2.0 mm 3
3 {Oligomyrmex frontalis}TL 1.9 mm; HL 0.73 HW 0.48 CI 82 SI 28; occipitum with a carina on each side, giving a dentate profile; head with pronounced frontal lobes; metanotal groove broad and well-marked, propodeum dorsum and declivity with obtuse angle and small lateral teeth; head densely reticulate punctate, pronotum reticulate-punctate, pedicel dorsum mostly smooth; colour brownish-yellow, gaster and mandibles darker Zare - frontalis
-- {Oligomyrmex diabolicus major}TL 1.4 mm, HL 0.56 HW 0.43 CI 78 SI 45; separable from frontalis by the angular protuberances of the anterior frontal carinae and the profile of the propodeum and petiole; major only known Chad - diabolicus
-- Frontal lobes small and hardly produced posterior of the antennal insertions 4
4 TL 1.5 mm; HL 0.67 HW 0.50 CI 75; head convex in front, occiput biconvex with a pair of lateral teeth, anterior clypeal margin produced as an emarginate lobe; eyes minute; propodeal teeth obtuse; shiny, head reticulate-punctate, pronotum dorsum smooth, rest of alitrunk and pedicel punctate, gaster smooth; colour yellowish-brown; soldier only known Uganda - convexus
-- Anterior clypeal margin with lateral carinae and straight to slightly concave anterior margin 5
5 {Oligomyrmex erythraeus}TL 1.6-1.8 mm; HL 0.6 HW 0.4 CI 71 SI 46; occiput with fine lateral carina terminating laterally in a small tooth; eyes of a single facet; clypeal margin projecting but not dentate; head and promesonotum shiny, with piligerous puncturations, head with longitudinal striations, rest of alitrunk and pedicel thickly punctate; pilosity short but abundant; colour yellow, head light brown .
. {Oligomyrmex erythraeus} Ethiopia - erythraeus
-- {Oligomyrmex thoracicus}TL 2.0 mm; HL 0.84-0.91 HW 0.55-0.58 CI 76 SI 54; occipital margin laterally carinate; frontal lobes small convex and not raised; metanotal area with apparent vestigial wing bases; propodeum with broadly divergent triangular teeth with even concavity between; shiny, head finely striate-punctate, alitrunk and pedicel densely and more coarsely punctate except dorsal areas which are smooth; colour bright ferruginous with brownish-yellow funiculi and legs Uganda - thoracicus
6 {Oligomyrmex latro}TL 2.1 mm; HL 0.8 CI 77 SI 51, one-fifth longer than wide; occipital margin without carinae, eyes rudimentary; metanotal groove deep but with a membranous band, propodeal teeth reduced to points; sculpturation fine, head longitudinally striate but very shiny, and medially smooth .
. {Oligomyrmex latro} Zare - latro
-- TL < 2.0 mm 7
7 Propodeum without distinct teeth; TL 1.4 mm; HL 0.60 HW 0.40-0.45 CI 67-75; head rectangular, occipital margin broadly impressed medially, corners rounded right angles; anterior clypeal margin sinuate with lateral blunt angles formed by carinae; eyes minute, no median ocellus; metanotal suture shallow; colour yellowish- brown - no images available
CAR - donisthorpei
-- Propodeum with distinct teeth, even if very small 8
8 {Oligomyrmex species E}HL one-fifth greater than HW; TL 1.56 mm HL 0.57 HW 0.47 CI 82 SL 0.28 SI 60; head with moderately convex sides; metanotal groove deep; colour yellow-brown Nigeria - new species - boltoni
-- HL at least one-quarter longer than HW 9
9 {Oligomyrmex santschii soldier head}HL one-third greater than HW; TL 1.7 mm CI 70 SI 54; propodeum with lateral carinae, concave between; almost all except parts of head densely punctate; colour light ferruginous Sudan - santschii
-- HL one-quarter greater than HW 10
10 {Oligomyrmex angolensis}TL 0.9-1.0 mm (but ssp congolensis TL 1.4-1.5 mm) CI 73 SI 72; propodeal teeth acute about as long as one-fourth their interval; pubescence mainly on head and appendages; colour reddish-yellow, head more red, gaster brownish-yellow .
. {Oligomyrmex angolensis} ? (Nigeria) species B - Angola and Zare - angolensis
-- {Oligomyrmex jeanneli}TL 1.7 mm CI 76 SI 61; head concave posteriorly, no anterior carinae on head; mandibles six-toothed; scape reaching mid-point of face, angles of occiput not raised; postpetiole distinctly wider than petiole; head mostly smooth and shiny, except for fine anterior and vertex striae; ? Aeromyrma according to inclusion in Weber (1952) key. Kenya - jeanneli
return to key subgenus Aeromyrma - based on Weber (1952) --
Minor only known Zambia - incertus
Minor only known Zimbabwe - khamiensis
Minor only known Zimbabwe - lucidus
Minor only known South Africa - traegaordhi
Minor (queen) only known Uganda - ugandanus
Minor only known Ghana - vorax
11 {Oligomyrmex alluaudi soldier}TL 1.5-1.6 mm CI 85 SI 54; HL one-fifth greater than HW, shorter than angolensis, sides parallel, occipital border feebly concave; metanotal groove deep, propodeum slightly raised declivity shorter than dorsum and concave, small slightly raised propodeal teeth; pubescence abundant; head reticulate-punctate except at sides, genae striate and shiny, most of alitrunk finely reticulate-punctate, gaster smooth and shiny; colour dull yellow, head more brown with black anterior border .
. {Oligomyrmex alluaudi major} Kenya - alluaudi
-- TL at least 2.0 mm 12
12 TL 2.0-2.5 mm 13
-- Oligomyrmex africanusTL 2.7-2.9 mm; HW ca 0.75 HL; head with anterior carinae; mandibles six-toothed; scape barely exceeding mid-point of face; occipital angles with a small tooth or horn; head shiny but finely reticulate; colour dirty yellow, head yellowish red Botswana - africanus
13 {Oligomyrmex hewitti soldier face}Occipital border near straight 14
-- {Oligomyrmex acutus soldier face}Occipital border deeply impressed 16
14 {Oligomyrmex arnoldiellus soldier face}{Oligomyrmex arnoldiellus soldier profile}TL 2.0 mm CI 82 SI 56; eyes indistinct, head striate; propodeum with smoothly rounded angle between dorsum and declivity; colour of head yellowish-brown, alitrunk more brown, gaster intermediate but anterior darker .
. {Oligomyrmex arnoldiellus soldier face}. South Africa - arnoldiellus
-- Propodeum with distinct angle between dorsum and declivity 15
15 Oligomyrmex hewitti head{Oligomyrmex hewitti soldier profile}TL 2.2 mm CI 76 SI 53; eyes distinct; metanotal groove quite wide and deep; head with anterior longitudinal striation and transverse posterior striation, occipital angles reticulate; postpetiole one and two-thirds wider than long; colour overall reddish-yellow, head and gaster darker .
. Oligomyrmex hewitti South Africa - hewitti
-- {Oligomyrmex nanus soldier profile}Head missing on sole example; metanotal groove feeble; colour overall brownish-yellow Mozambique - nanus
16 Occipital angles rounded and right-angled or obtuse 17
-- {Oligomyrmex acutus soldier face}Occipital angles acute; TL 2.1 mm HL 0.87 HW 0.55 CI 74 SI 49 AL 0.60; well developed propodeal spines; head reticulate-punctate, struate anteriorly; colour brown with head distinctly lighter than gaster Zare - acutus
17 {Oligomyrmex petulcus soldier face}Propodeum dentate; TL 2.5 mm HL 0.84 HW 0.55 CI 80 SI 50 AL 0.63; postpetiole twice as wide as long; queen only known; colour ferruginous .
. {Oligomyrmex petulcus major} Zare - petulcus
-- {Oligomyrmex debilis soldier face}Propodeum edentate; size larger, TL 2.5-2.6 mm CI 73 SI 56; postpetiole one and two-thirds wider than long; occiput submatt, densely but finely sculptured; colour reddish-yellow, gaster darker .
. {Oligomyrmex debilis major} Guinea - debilis
return to key subgenus Aneleus --
Oligomyrmex paetus queenQueen only known; TL 4.5 mm, alitrunk dark brown, gaster lighter, head black - photographs on species page
Angola - paetus
Minor & queen only known Panafrican - politus
Minor only known Kenya - punctatus
Bernard in new genus Nimbamyrma - worker only (may well be synonymous with politus) Guinea - villiersi
18 Occiput with lateral carination and distinct elongate processes 19
-- Occiput without lateral carination 20
19 {Oligomyrmex diabolus}TL 2.4-2.6 mm; CI 77 SI 40; matt and densely reticulo-punctate; colour yellow slightly rust, head brownish-red, gaster yellow grey .
. {Oligomyrmex diabolus major} Cameroun, CAR - diabolus
-- {Oligomyrmex Cameroun nsp}TL ca 2.7 mm HL 1.06 HW 0.82 CI 78 SL 0.36 SI 44 PW 0.50
sculpturation limited; the head with very fine anterior longitudinal striations, that in angled light can be seen to persist as very faint lines on the posterior of the head; propodeum without teeth, angle between dorsum and declivity defined but rounded, declivity with fine margination; erect pilosity, distinctly golden yellow but limited to anterior of head, several erect hairs on the alitrunk  semi-decumbent hairs on the pronotum and the apex of the gaster; overall, including appendages, with quite abundant long sub-erect long golden yellow pubescence; overall colour golden yellow, darker on head and gaster, mandibles yellow-brown
Cameroun - new species Cameroun
20 {Oligomyrmex perpusillus}Occiput with distinct transverse margination; TL 2.0-2.5 mm CI 81 SI 47; colour reddish-yellow, head rufous and shiny, meso- and metapleura closely punctured and dull .
. {Oligomyrmex perpusillus} East & South Africa - perpusillus
-- Occiput with transverse striations but not a distinct transverse margination 21
21 {Oligomyrmex menozzii}TL 3.2-3.5 mm CI 85 SI 43; eyes very small with 2-3 ommatidia; gaster with markedly concave anterior where postpetiole attached; occiput and dorsal alitrunk transversely rugose; sparse yellowish pilosity; colour rust-red, clypeus and mandibles red-brown, appendages paler Fernando Po I. & Gabon - menozzii
-- {Oligomyrmex silvestrii}TL 2.0-2.5 mm CI 88 SI 49; mandibles 5-toothed; eye of 6-8 ommatidia; propodeum with strong lateral margination and two strong teeth; head puncturate with longitudinal anterior striations and transverse rugae on occiput; alitrunk punctate, very dense on propodeum, pedicel nodes near smooth, gaster smooth; pilosity yellowish, sharp and curved; colour testaceous red .
. {Oligomyrmex silvestrii} Ghana & Guinea - silvestrii
Contents MYRMICINAE Introduction
2007, 2008, 2010, 2013, 2015 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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