SUBFAMILY MYRMICINAE - Genus Oligomyrmex
Key to major workers
|
|
The Ants of
Africa SUBFAMILY MYRMICINAE - Genus Oligomyrmex Key to major workers |
| Contents - Myrmicinae - MYRMICINAE Introduction |
Key to major or soldier morph (CI and SI mostly
derived from the original illustrations)
| 0 |  Queen 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 |  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 |  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 |
Zaïre - frontalis |
| -- |  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 |  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 |
. |
| . |  |
Ethiopia - erythraeus |
| -- |  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 |  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 |
. |
| . |  |
Zaïre - 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 |  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 |  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 |  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 |
. |
| . |  |
? (Nigeria) species B - Angola and Zaïre - angolensis |
| -- |  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 |
 |
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 |  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 |
. |
| . |  |
Kenya - alluaudi |
| -- | TL at least 2.0 mm | 12 |
| 12 | TL 2.0-2.5 mm | 13 |
| -- |  TL 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 |  Occipital
border near straight |
14 |
| -- |  Occipital border
deeply impressed |
16 |
| 14 |   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 |
. |
| . |  . |
South Africa - arnoldiellus |
| -- | Propodeum with distinct angle between dorsum and declivity | 15 |
| 15 |  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 |
. |
| . |  |
South Africa - hewitti |
| -- |  Head missing
on sole example; metanotal groove feeble;
colour overall brownish-yellow |
Mozambique - nanus |
| 16 | Occipital angles rounded and right-angled or obtuse | 17 |
| -- | 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 |
Zaïre - acutus |
| 17 |  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 |
. |
| . |  |
Zaïre - petulcus |
| -- |  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 |
. |
| . |  |
Guinea - debilis |
|
subgenus Aneleus | -- |
| ¤ |  Queen 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 |  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 |
. |
| . |  |
Cameroun, CAR - diabolus |
| -- |  TL ca 2.7 mm HL 1.06 HW
0.82 CI 78 SL 0.36 SI 44 PW 0.50sculpturation 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 |  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 |
. |
| . |  |
East & South Africa - perpusillus |
| -- | Occiput with transverse striations but not a distinct transverse margination | 21 |
| 21 |  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 |
| -- |  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 |
. |
| . |  |
Ghana & Guinea - silvestrii |
 |
MYRMICINAE Introduction |
© 2007, 2008, 2010, 2013, 2015 - Brian Taylor CBiol
FSB FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K. |
href="oligomyrmex_major_key.htm"