The Ants of Africa
SUBFAMILY MYRMICINAE - Genus Monomorium key to species-groups and component species
Monomorium Introduction

Compiled largely from the groupings used by Bolton (1987). A few curious points are as follows:
As the final column shows a number of species appear in Bolton's key in what appear to be odd places relative to other members of a species-group or species complex, e.g. Monomorium emeryi in the destructor-group; hannonis in the setuliferum-complex; hirsutum in the bicolor-complex.
The australe-complex of small to minute species contains what appears to be a proliferation of species, primarily by raising early so-called varieties to full species status, but Bolton did not give a single illustration for any of the twelve members.

Note: Following the genus redefinitions in Ward et al. (2014: 10) the Syllophopsis from sub-Saharan Africa are arnoldi (revived from renaming as jonesi), cryptobia, elgonensis, malamixta, modesta, sersalata and thrascolepta.
Trichomyrmex
from sub-Saharan Africa are - abyssinicus, plus "destructor-group" - destructor, emeryi, epinotale, mayri, oscaris and robustior.

Species-group
(some = former sub-genus)
subdivision into complexes
No of members Species Bolton (1987)
key couplet
Mandibles with 5 teeth
latinode-group 1 In full-face view head ovoid/rectangular, eyes set well forward; TL 2.6-3.2 mm
. . {Monomorium latinode face}latinode - tramp species - Tanzania - new genus definition pending (note in Ward et al 2014)
78
Mandibles with 3-4 teeth
Genus Trichomymrex part
(
scabriceps-group; Holcomyrmex, Bolton, 1987: 320)
1 {Holcomyrmex alitrunk}Mandibles unsculptured; propodeal spiracle a short, near vertical, slit; polymorphic
. . trichomyrmex abyssinicus majorTrichomyrmex abyssinicus - TL 2.6-6.7 mm, HL 0.68-2.04; polymorphic, although exhibiting monophasic allometry; granivorous with heavy mandibles; colour of larger workers reddish brown to darker on head and alitrunk, gaster darker again, smaller workers much lighter, still with gaster lighter - across whole of Sahel zone 59
Propodeal spiracle circular or nearly so
Propodeal dorsum either unsculptured or weak sculpture that is not transverse next stage of key
Genus Trichomyrmex part
(formerly Monomorium destructor-group
(Parholcomyrmex)
6 Propodeal dorsum always sculptured (even if faintly), usually transversely striate or costulate; with distinct angle at junction of propodeal dorsum & declivity (the angle may be rounded to sharp)
. . Trichomyrmex emeryi Trichomyrmex emeryi - dorsal surfaces evenly and coarsely sculptured; TL 2.5-3.4 mm - southern Africa 09
. . More weakly sculptured .
. . Trichomyrmex epinotaleTrichomyrmex epinotale - head and gaster yellow, alitrunk contrasting brown; TL 2.2-2.3 mm - Zare - probable junior synonym of oscaris see below
62 & 85
. . Not contrastingly coloured .
. . {Trichomyrmex mayri} Trichomyrmex mayri - head and alitrunk brown and with range of sizes (TL ca 2 mm) - Sahel Zone 64 & 86
. . {Trichomyrmex mayrimayri .
. . {Trichomyrmex robustior}Trichomyrmex robustior - head and alitrunk brown but uniformly sized; TL 2.5-3.4 mm - trans-soudanosavannah from Somalia west to Senegal
64
. . {Trichomyrmex robustior}robustior .
. . {Trichomyrmex destructor major} Trichomyrmex destructor - head and alitrunk yellow; petiole subglobular in dorsal view; TL 1.8-3.5 mm - widespread tramp species
Major
65 & 87
. . {Trichomyrmex destructor minor}Minor .
. . {short description of image}Trichomyrmex oscaris major head with distinct longitudinal rugae on genae; dorsum more weakly sculptured but strong transversely on propodeum; head and alitrunk yellow, petiole profile compressed and ovoid in dorsal view; monophasic allometry: TL 1.6-3.8 mm - pan-African savannah and open areas 09 & 65 & 87
. . {Trichomyrmex oscaris major}oscaris major worker .
. . {Trichomyrmex oscaris minima}oscaris minima worker .
Propodeal dorsum smooth or with weak sculpture that is not transverse
Eyes with more than 2 ommatidia next stage of key
Genus Syllophopsis
(formerly Monomorium fossulatum-group)
7 Eyes minute (1-2 ommatidia only); mandibles smooth; propodeum mostly with small tubercles at junction of dorsum and declivity
. . {short description of image} Syllophopsis modesta - metanotal groove visible but only slightly impressed; TL 1.7-2.0 mm - east and southern Africa (plus an Ivory Coast population) 67
. . {Syllophopsis modestum}modesta .
. . Metanotal groove a V- or U-shaped impression .
. . Blackish or blackish brown .
. . Syllophopsis malamixtum Syllophopsis malamixta - lower mesonotum sculptured, propodeum with narrow transverse ridge; TL 1.6-2.0 mm - West Africa 69
. . Syllophopsis cryptobia Syllophopsis cryptobia - lower mesonotum smooth; propodeum without a narrow transverse ridge but with distinct minute tubercles at the postero-lateral angles; TL 1.3-1.7 mm; colour usually dull yellow to light brownish yellow - West Africa & Congo Basin
69 & 71
. . {Syllophopsis cryptobia}cryptobia .
. . Yellow .
. . Syllophopsis sersalata - lower mesonotum sculptured; TL 2.2 mm - RwandaSyllophopsis sersalata 70
. . Lower mesonotum smooth .
. . Syllophopsis elgonensis Syllophopsis elgonensis - antennal scapes relatively short, SI 91-95; TL 1.9-2.0 mm - Kenya 72
. . Syllophopsis elgonense .
. . Scapes relatively long, SI 103-100 .
. . {short description of image} Syllophopsis arnoldi (jonesi) - head and scapes with only very short pubescence; TL 2.2-2.3 mm - South Africa 73
. . Syllophopsis arnoldi .
. . {short description of image} Syllophopsis thrascolepta - head and scapes with dense erect pubescence; TL 1.9-2.2 mm - Ivory Coast 73
. . {Monomorium thrascolepta}thrascolepta .
Genus Monomorium
Frontal lobes not very close and propodeum rounded next stage of key
hanneli-group 5 {Monomorium invidium}Frontal lobes set close together; propodeum angular to bidentate in profile
. . {short description of image} guineense - both pedicel segments with narrow profile and postpetiole wider than petiole; TL 2.3 mm - Guinea to Cameroun
90
. . {short description of image} guineense .
. . Postpetiole with lower domed node .
. . Light to medium-brown .
. . {short description of image} hanneli - eye with more than 10 ommatidia; TL 2.4-2.8 mm - East Africa (Angola?); includes former valtinum (eye with only 6-7 ommatidia; TL 1.8-1.9 mm - Kenya) 82
. . {Monomorium hanneli}hanneli .
. . Dark brown to near black .
. . {short description of image} invidium - propodeum dorsum weakly sculptured; TL 1.8-2.0 mm - West Africa 81 & 90
. . {Monomoriuum invidium}invidium .
. . {Monomorium jacksoni}jacksoni - propodeum dorsum transversely rugose, rest of alitrunk quite strongly sculptured; pronotum distinctly laterally marginate; TL 1.8-2.0 mm - Cameroun & Congo
80
Eyes oval or circular next stage of key
setuliferum-group 8 {Monomorium macrops}Eyes set forward of mid-point of head and reniform or at least drawn to a point ventrally in profile
macrops-complex 1 With a narrow head; also mesonotum and propodeum without standing hairs .
. . {short description of image} macrops - light to medium brown; TL 2.0-2.1 mm - South Africa 61
. . Monomorium macrops .
setuliferum-complex 5 Head and alitrunk sculptured, often densely .
. . Monomorium hannonishannonis - with numerous erect hairs; densely sculptured, brown; TL 2.7-2.8 mm - Congo Basin 08
. . With no erect hairs on head or body .
. . {short description of image} alamarum - weakly sculptured, dark brown;TL 2.0-2.4 mm - Namibia
The drawing appears to be incorrect!
25
. . Monomorium alamarumalamarum 25
. . Strongly sculptured .
. . {short description of image} nyasae - small eyes, cinnamon yellow, with some darker areas; TL 2.5 mm - Malawi
21
. . Monomorium notulumnotulum - large eyes but not strongly reniform, brown, usually with gaster darker; TL 2.0-2.4 mm - southern Africa
may = the Bolton (1987) description of ebangaense
21
. . {short description of image} setuliferum - large eyes which are conspicuously reniform; variable yellow to quite dark yellow-brown; TL 2.5-2.7 mm - Botswana 20
. . Monomorium setuliferum .
havilandi-complex 2 Smooth and unsculptured, also with numerous erect hairs (members seem lumped together) .
. . {short description of image} havilandi - mandibles with only three teeth, uniformly blackish-brown to black, gaster often shiny jet black, TL 2.8-3.1 mm - South Africa 61
. . {Monomorium havilandi}havilandi .
. . {short description of image} xanthognathum - mandibles falcate; glossy blackish-brown, mandibles conspicuously bright yellow; TL 2.5-2.7 mm - South Africa 88
. . Monomorium xanthognathum .
Eye set around mid-point of side of head and not reniform or elongated
Propodeal dorsum unsculpturednext stage of key
salomonis-group
(Xeromyrmex)
48 Propodeum with dense very fine granular or reticulo-punctate sculpturation; antennae with 12 segments; alitrunk dorsum without any standing hairs
Head weakly sculptured to near smooth next stage of key
Head uniformly and densely sculptured
. {short description of image}Uniform yellow-orange colour other than variable darker shade to apex of gaster - next stage of key
. {Monomorium bicolor}Orange-red; gaster dark near black - next stage of key
. {Monomorium afrum}Head, alitrunk and gaster uniformly dull brown; in most petiole with relatively short stout pedicel - next stage of key
pharaonis-complex 1 .
. . {Monomorium pharaonis}pharaonis - TL 2.2-2.4 mm; yellow-orange, apex of gaster dark; head, alitrunk and pedicel finely and densely reticulopunctate; erect hairs relatively long and moderately abundant on the head and gaster; antennae 12-segmented; sides of head convex in front view with a smooth curve to a slightly convex occipital margin - pan-global tramp 14
. . {Monmomorium pharaonis}pharaonis .
bicolor-complex 6 .
. . Pronotum dorsum with erect hairs .
. . {Monomorium nitidiventre} nitidiventre - pronotum dorsum with a pair of hairs at the anterior angles; TL 2.5-2.8 mm; head rather shorter and scapes not or barely reaching occiput; head with more numerous psammophore type hairs on underside; also head and alitrunk shiny; gaster also shiny with a bluish sheen - Sudan, Tanzania NA
. . {Monomorium nitidiventre}nitidiventre .
. . {Monomorium hirsutum}hirsutum - pronotum dorsum with many erect hairs; also with small eyes; TL 3.2-3.4 mm; overall orange-yellow to orange-red, gaster blackish-brown to black - Eritrea 07
. . Without erect hairs on pronotum .
. . {Monomorium niloticum} niloticum - TL 3.0-3.3 mm; head larger in front than behind; eyes relatively large; head, alitrunk and petiole very finely shagreened, slightly shiny, gaster almost smooth and brilliant; colour of head, alitrunk, petiole and legs yellow-red; gaster black - Sudan, Egypt NA
. . {Monomorium niloticum}niloticum - much more distinctly shiny
.
. . {Monomorium niloticum}niloticum niloticoides -overall finely sculptured giving a matt appearance
.
. . {Monomorium bicolor} bicolor - TL at least 2.9 mm; base of gaster dorsum with sparse pilosity, usually only 1-3 pairs of hairs - very widespread north of the Equator 42
. . {Monomorium bicolor}bicolor .
. . {short description of image} ebangaense - TL 2.2 mm, red promesonotum lighter, gaster black; confused status - Angola (key misleading)
. . Base of gaster dorsum with 6-8 or more pairs of hairs .
. . {short description of image} rufulum - with well developed ammochaete hairs on underside of head; TL 3.0-3.6 mm; dull orange to reddish-brown on all but gaster, which is darker brown to blackish-brown often with a paler spot or streak antero-medially - southern Africa 13 & 40
.
.
Monomorium rufulumrufulum

. . With no more than short hairs on underside of head .
. . {short description of image} personatum - with relatively large eyes 0.31-0.33 X HW; TL 3.3-3.3 mm; head and alitrunk bright red but anterior of head, scapes and antennal club darkish brown - Angola 41
. . Monomorium personatum .
. . With smaller eyes, 0.23-0.27 X HW .
. . {short description of image} westi - anterior margin of clypeus concave, with lateral projecting teeth; TL 3.0-3.2 mm; all except gaster orange to dull orange, the gaster strongly contrasting blackish-brown to black - Kenya 43
. . monomorium westi .
. . Monomorium dictator dictator - anterior margin of clypeus only weakly concave and without projecting lateral teeth; TL 2.9 mm; generally red to orange-red except wholly blackish-brown to black gaster - Angola & Gambia 43
opacum-complex 6 .
. . Pronotum dorsum with erect hairs .
. . {Monomorium albopilosum}albopilosum - pronotum dorsum and propodeum dorsum with erect hairs, TL 3.4-4.4 mm; uniform light to dark brown - southern Africa 07
. . {Monomorium albopilosum}albopilosum .
. . Monomorium junodijunodi - propodeum dorsum without erect hairs; TL 2.8-3.6 mm; uniform medium to dark brown - south-eastern Africa 14
. . Pronotum dorsum without erect hairs .
. . {Monomorium afrum}afrum - first tergite of gaster without erect hairs; TL 3.6-4.3 mm; head in profile with a distinct posteroventral occipital angle; uniform medium to dark brown - sub-Saharan Africa except far south 22
. . {Monomorium afrum}afrum .
. . First tergite of gaster with erect hairs .
. . micropacum - first tergite of gaster with about 10 pairs of hairs; smaller TL 2.4 mm; dull light brown - South AfricaMonomorium micropacum 38
. . First tergite of gaster with only 1-2 pairs of hairs anterior to apical row; larger .
. . Monomorium opacumopacum - propodeum profile almost horizontal with smooth transition into declivity; TL 3.3-3.5 mm; yellowish to pale medium brown - eastern Africa 39
. . Monomorium subdentatumsubdentatum - propodeum profile sloping posteriorly, with angled transition into declivity; TL 3.1-3.3 mm; yellowish to pale medium brown - Zare 39
Head weakly sculptured to near smooth
Petiole with a short peduncle
. {short description of image}Distinctive large eyes and near square heads; head with sculpturation of fine reticulation overlayed by fine striations - areniphilum-complex - next stage of key
. {short description of image}Reduced sculpturation, so generally quite shiny - salomonis-complex - next stage of key
. {short description of image}Head much less strongly or distinctly sculptured; in most petiole with moderate pedicel subtended by a blunt process; generally brownish, with lighter appendages - subopacum-complex - next stage of key
Petiole with a relatively long peduncle
. {short description of image}Sculpturation even more reduced, with head and alitrunk similar - tchelichofi-complex - next stage of key
. {short description of image}Much reduced sculpturation, large eyes and long to very long scapes; elongated overall shape - viator-complex - next stage of key
. With reduced sculpturation and reduced pilosity (a catch-all collection) - mediocre-complex - next stage of key
. Small to minute species, with fine sculpturation giving silky appearance [Curiously there are no illustrations in the literature - despite the proliferation of species by Bolton, 1987] - australe-complex - next stage of key
areniphilum-complex 2 Distinctive large eyes and near square heads; head with sculpturation of fine reticulation overlayed by fine striations
. . {Monomorium areniphilum}areniphilum - distinctive large eyes, HW = HL; head with sculpturation of fine reticulation overlayed by fine striations; TL 3.1-4.3 mm; variable brown - Sahel zone 23 & 51
. . {Monomorium areniphilum}areniphilum .
. . {Monomorium pullulum} pullulum new status - TL 3.7-4.0 mm; head about 1/6 longer than wide, with convex sides and straight occipitum; black with a little brownish; mandibles, funiculi, anterior of pronotum, base of petiole, genae and tarsi reddish-brown; densely reticulate, granular and matt - Sahel zone not in key
. . {Monomorium pullulum}pullulum .
salomonis-complex 2 Reduced sculpturation, so generally quite shiny
. . {Monomorium salomonis} salomonis - TL 2.5-3.5 mm; moderately shiny; variably coloured brown with gaster darker - widespread tramp not in key
. . {Monomorium salomonis}salomonis .
. . Monomorium hercules hercules - TL 3.1-3.6 mm; dark red brown, with redder mandibles - Sudan -seems likely to be a junior synonym of salomonis
not in key
subopacum-complex 8 Head much less strongly or distinctly sculptured; in most petiole with longer pedicel subtended by a blunt process; generally brownish, with lighter appendages
. . {short description of image} delagoense - pronotum dorsum with erect hairs; TL 3.1-3.9 mm; uniform dark brown - Mozambique & South Africa 15
. . Monomorium delagoense 15
. . Pronotum dorsum without erect hairs .
. . Dorsum of head with no more than faint patterning, polished and shiny
drapenum - dorsum of head with erect hairs; TL 2.4-2.6 mm; head and gaster dark brown, remainder lighter - NamibiaMonomorium drapenum
32
. . Monomorium drapenum .
. . Dorsum of head without erect hairs .
. . Monomorium ophthalmicumophthalmicum - with relatively large eyes and short scapes; mesonotum dips to metanotal suture but that is not impressed; TL 2.3 mm; medium brown, legs and antennae dull yellow - Ethiopia 31
. . kitectum - alitrunk with smooth near flat profile; TL 2.2-2.3 mm; brown wth gaster darker - NamibiaMonomorium kitectum 32
. . Monomorium kitectum .
. . {short description of image} willowmorense - alitrunk with impressed metanotal suture, TL 2.5-3.0 mm; medium brown, gaster usually darker - South Africa 32
. . Monomorium willowmorense .
. . Dorsum of head with distinct sculpturation, at least enough to give dull appearance .
. . Monomorium ocellatumocellatum - first gastral tergite with numerous evenly distributed erect hairs; TL 3.1-3.7 mm - South Africa 48
. . First gastral tergite with sparse erect hairs .
. . Monmorium hereroherero - anterior clypeal margin straight; dorsum of head with 3-4 pairs of erect hairs; TL 2.8-3.1 mm - Namibia 53
. . {short description of image} subopacum - anterior clypeal margin indented; TL ca 2.4 mm - widespread semi-desert species in northern Africa, introduced to South Africa
Note Bolton (1987) had TL 3.1-3.4; Mayr (1861: 72) for mediterraneum had TL 2.8-3.0 ; yellowish brown-red; gaster darker than head and alitrunk
53
tchelichofi-complex 5 Sculpturation even more reduced, with head and alitrunk similar
. . Promesonotum with erect hairs .
. . {short description of image} excelsior - glossy dark brown, TL 3.3-3.5 mm - South Africa 11
. . Monomorium excelsior .
. . Monomorium ilgiiilgii - uniform yellow, TL 2.7-3.1 mm - Ethiopia 11
. . Promesonotum without erect hairs .
. . {Monomorium orangiae} orangiae - promesonotum sculpture almost effaced, propodeum with distinct lateral margination; petiole node smooth; TL 3.7-4.0 mm; uniform dark glossy brown - South Africa 34
. . {Monomorium orangiae}orangiae .
. . Promesonotum with fine but distinct sculpture, also on petiole node .
. . Monomorium fridaefridae - TL 3.1-3.2 mm; HW 0.67-0.68; SI 101-103; glossy chestnut brown - South Africa 35
. . Monomorium tchelichofitchelichofi - TL 3.8-4.0 mm; HW 0.74-0.82; SI 95-100; dark brown, gaster darker - South Africa 35
viator-complex 4 Much reduced sculpturation, large eyes and long to very long scapes; elongated overall shape
. . Without erect hairs on the alitrunk .
. . Monomorium mantazenummantazenum - relatively small eyes; TL 2.7-3.0 mm; black to blackish-brown, mandibles yellow - Namibia 46
. . {Monomorium viator} viator - with extremely large eyes, 0.37-0.40 X HW, TL 3.0-3.7 mm; alitrunk yellowish orange to reddish brown, head and gaster usually darker, appendages dull yellow - Namibia 28
. . {Monomorium viator} .
. . With erect hairs on the alitrunk .
. . {short description of image} marshi - TL 2.7-3.2 mm; alitrunk light to dull orange, gaster dark brown to black - Namibia 16
. . {short description of image} .
. . {short description of image} vatranum - TL 2.7-3.0 mm; usually very dark brown - Namibia 16
. . Monomorium vatranum .
mediocre-complex 6 With reduced sculpturation and reduced pilosity (a catch-all collection) - all small species
. . Eyes set at the mid-point of the head .
. . Monomorium nirvanumnirvanum - petiole node with a single pair of erect hairs projecting posteriorly; TL 2.1 mm; SI 95-100; light yellowish-brown - Namibia 26
. . {short description of image} mediocre - petiole node without erect hairs; TL 1.9-2.0 mm, SI 90-93; yellow - Zimbabwe & South Africa 27
. . Monomorium mediocre .
. . Eyes set at least slightly forward of mid-point of the head .
. . Dorsum of head finely sculptured .
. . {Monomorium osiridis} osiridis - TL 1.7-1.9 mm; with fine shagreening on dorsum of head; uniform dull yellow - Kenya & Gambia 76
. . {Monomorium osiridis}osiridis
. . esharre - with relatively narrow head; TL 1.9-2.0 mm; head and gaster blackish-brown, alitrunk lighter brown - NamibiaMonomorium esharre 27
. . Dorsum of head almost smooth .
. . rabirium - very faintly sculptured but pronotal dorsum reticulate to shagreened; TL 1.7 mm, SI 92.97; yellow - NamibiaMonomorium rabirium 25 & 77
. . Monomorium zuluzulu - very similar but pronotal dorsum unsculptured; TL 1.7-1.9 mm; SI 85-88 - South Africa 77
australe-complex 12 Small to minute species, with fine sculpturation giving silky appearance [Curiously there are no illustrations in the literature - despite the proliferation of species by Bolton, 1987; the placement of senegalense seems likely to be wrong]
. . senegalense - status dubious - TL 3.5-3.8 mm (Roger, 1862c) - Senegal o
A . With numerous erect hairs on first gastral tergite in addition to apical row .
. . Alitrunk and gaster similarly coloured not contrasting .
. . {Monomorium carbo}carbo - uniformly brown; TL 2.3-2.4 mm, SI 102-107 - Ethiopia 47
. . Monomorium minorminor - uniformly yellow; TL 2.6-2.9 mm, SI 108-116 - southwest Africa 47
. . Alitrunk and gaster obviously contrasting .
. . {Monomorium dakarense}dakarense - eye with 7-8 ommatidia in longest row; TL 2.2-2.3 mm; head and alitrunk orange-yellow, gaster blackish-brown - Senegal & Gambia 49
. . Monomorium parvinodeparvinode - eye with 10 ommatidia in longest row; TL 2.2 mm; head and alitrunk medium yellowish-brown - north-east Africa 49
B . With no more than 1-3 pairs of erect hairs on first gastral tergite .
. . Monomorium sutusutu - eye with more than 10 ommatidia in the longest row; TL 2.7-3.0 mm; head yellowish-brown, promesonotum slightly darker but remainder much darker, gaster very dark brown - Kenya 52
. . Eye with 7-9 ommatidia in the longest row .
. . Monmorium disertumdisertum - with relatively short scapes, TL 2.0-2.2 mm SL 0.40-0.43; SI 89-93; pale brownish yellow, gaster may be darker - Zimbabwe 54
. . Scapes with SL 0.47-0.57, SI 100-110 .
. . Head strongly sculptured, shagreened, dull & opaque .
. . Monomorium damarensedamarense - dorsum of head without erect hairs; TL 2.2-2.8 mm; eyes 0.27-0.31 X HW; light to medium brown - southern Africa 23 & 56
. . opacior - dorsum of head with 2 pairs of erect hairs behind level of frontal lobes; TL 2.2-2.4 mm, eyes 0.24-0.26 X HW; dull light brown, gaster much darker - Namibia & BotswanaMonomorium opacior 56
. . Head very weakly sculptured, near smooth and weakly shining .
. . termitarium - TL 2.5-2.6 mm; entirely yellow - BotswanaMonomorium termitarium 57
. . Head & alitrunk medium brown, gaster dark brown .
. . Monomorium ancepsanceps - pronotal dorsum finely shagreened, with rough appearance but mesonotum contrasting reticulo-punctate; TL 2.5-2.6 mm, HW 0.47, SL 0.47 - South Africa 58
. . Monomorium australeaustrale - pronotal dorsum finely reticulate and mesonotum more strongly so but not contrasting; TL 2.5-2.6 mm, HW 0.50-0.52 SL 0.50-0.54 - South Africa 58
Propodeal dorsum unsculptured
monomorium-group
(Monomorium)
69 Antennae with 11-12 segments; alitrunk dorsum with standing hairs, at least on pronotal humeri
. Antennae 12-segmented next stage of key
. Antennae 11-segmented
. Scapes reaching or surpassing the occiput, SI 95-102 (otherwise grouped with species with 12-segmented antennae)
. . {short description of image} strangulatum - TL 1.8-2.0 mm; all over dark brown, except for contrasting yellow appendages - West Africa & Congo Basin (in strangulatum-complex, Bolton, 1987)
146
. . {Monomorium strangulatum Gabon}strangulatum .
. . {short description of image} clavicorne - antennae 11-segmented; TL 1.4 mm; head an elongated rectangle; eyes set forward of midline of head; yellow or pale testaceous - Extra-limital, plus Sudan and Senegal
not in key
. Scapes not reaching occiput SI usually < 95
. {short description of image}Large relatively high postpetiole, convex propodeum - bequaerti-complex - next stage of key
. {short description of image}Eyes reduced with a ring of ommatidia enclosing a single longitudinal row of 2-4 ommatidia; propodeal profile in most a shallow smooth curve - boerorum-complex; Lampyromyrmex sub-complex - next stage of key
bequaerti-complex 3 Large postpetiole which is almost as voluminous as petiole; propodeum convex
. . {Monomorium rosae} rosae - blackish-brown to jet black; TL 1.6-2.0 mm - West Africa 150
. . {Monomorium rosae}rosae .
. . {short description of image}bequaerti - light glossy brown; in dorsal view both petiole and postpetiole longer than wide; TL 1.9 mm - Zare 151
. . {Monomorium bequaerti}bequaerti .
. . {short description of image} pulchrum - head and alitrunk glossy dull yellow to pale brown, gaster darker; in dorsal view both petiole and postpetiole shorter than wide; TL 1.7-1.9 mm - Zimbabwe 151
. . Monomorium pulchrum .
boerorum-complex -
sub-complex A
(Lampyromyrmex)
7 Convenience lumping of other species with 11-segmented antennae; eyes reduced with a ring of ommatidia enclosing a single longitudinal row of 2-4 ommatidia; propodeal profile in most a shallow smooth curve
. . {short description of image} guillarmodi - alitrunk dorsum without erect hairs; TL 1.6-1.7 mm; glossy light medium brown - Lesotho 145
. . Alitrunk dorsum with erect hairs .
. . {short description of image} spectrum - distinctively coloured with white legs contrasting with glossy dark brown body; TL 1.2-1.3 mm - Gabon 147
. . Pronotum dorsum anteriorly with a single pair of long erect hairs .
. . {short description of image} taedium - larger, TL 1.6-1.7 mm, dark brown - South Africa 153
. . {Monomorium mictilis} mictilis - TL 1.2-1.3 mm; dull yellow - eastern & southern Africa - note Bolton (1987: 320) separated this as having the head with a noticeably depressed profile (both upper and lower surfaces) - the head of the type specimen (Antweb photo) is not depressed! Fresh specimens have the posterior half of the gaster dark contrasting with the otherwise quite bright yellow of the head and body 154
. . {Monomorium mictilis}mictilis

. {short description of image} fastidium - TL 1.4 mm; uniform dull pale yellow - South Africa - possible junior synonym of mictilis 154
. . Pronotum dorsum with two pairs of long erect hairs anteriorly .
. . {short description of image} exiguum - anterior half of pronotum dorsum lacking a clump of 4 or more erect hairs; petiole short with a short anterior ventral process; TL 1.5-1.7 mm; variable clear yellow to dark brown (possibly a mixture of similar species) - Pan-African forests 155
. . {Monomorium exiguum type}exiguum type form .
. . {Monomorium exiguum faurei}exiguum minutissimum form .
. . {Monomorium exiguum faurei}exiguum faurei form .
. . {Monomorium vaguum} vaguum - anterior half of pronotum with a clump of 4 or more erect hairs; TL 1.3-1.4 mm CI 76-82; eye near circular, EI 20-23; dull yellow to medium brown (possibly a mixture of similar species) - widely distributed

155
. . {Monomorium vaguum}vaguum .
. . {Monomorium atomum} atomum - promesonotum profile more convex; erect hairs appear finer; TL 1.2-1.3 mm CI 76; eye longitudinally ovoid, EI 17; yellow to reddish yellow; entirely smooth and very shiny - Egypt across South Asia

extralimital
. Antennae 12-segmented
. Petiole node in profile a high narrow conenext stage of key
. Petiole node in profile a low cone
. {short description of image}Clypeal carinae sharp and close together, eyes round or near round; scapes relatively long SI 95-110 - schultzei-complex - next stage of key
. {short description of image}Like schultzei-complex but eyes more elongate and scapes relatively short, failing to reach the occiput (just reach in binatu) - rhopalocerum-complex - next stage of key
. {short description of image}Sharp but well-separated clypeal carinae, without anterior teeth; scapes surpass occiput - strangulatum-complex - next stage of key
. {short description of image}Eyes smaller and set well forward; petiole subconical - leopoldinum-complex [Note - leopoldinum itself is a junior synonym of madecassum according to Hetterick (2002) - next stage of key
Petiole node in profile a high narrow cone
. Large size, small eyes, short scapes & very dense pilosity - iyenasu-complex (single species) - next stage of key
. {short description of image}Distinctive high petiole node; scapes not reaching occipitum; clypeus with sharp carinae set close together and projecting at the anterior clypeal margin - altinode-complex - next stage of key
. {short description of image}Large eyes at least 0.30 X HW and set well forward; petiole subconical in profile - katir-complex - next stage of key
. {short description of image}Petiole node high, narrow or cuneate in profile, petiole with pronounced antero-ventral process - malatu-complex - next stage of key
. Residual "convenience" lumping of 15 species - boerorum-complex - next stage of key
. . {short description of image} monomorium - with thick erect hairs all over; TL 1.5-1.7 mm; piceous, very shiny, smooth - extra-limital and included for comparison not in key
.
.
Monomorium monomoriummonomorium
.
altinode-complex 9 Distinctive high petiole node; scapes not reaching occipitum
. . {short description of image} mirandum - strikingly bicoloured, clear yellow except for alitrunk, petiole and postpetiole which are black or blackish-brown; TL 1.8-1.9 mm - Kenya 99
. . Various colours but not strikingly bicoloured .
. . Propodeal spiracle a conspicuous circle .
. . Monomorium occidentale occidentale - anterior clypeal margin with a carinae extended to form a pair of elongate teeth; TL 1.8-2.1 mm; dark brown, gaster often darker - West Africa 114
. . Monomorium captatorcaptator - anterior clypeal margin with carinae forming no more than denticles; TL 1.8-1.9 mm; glossy dull yellow, head slightly darker than alitrunk - Congo Basin 117
. . Propodeum spiracle a small to minute circular opening .
. . {Monomorium vonatu}vonatu - both petiole and postpetiole with a sharp margin around sides and dorsum; TL 2.0 mm; glossy black - Ghana & Gambia 119
. . Petiole and postpetiole not sharp edged .
. . {short description of image}angustinode - propodeum with spiracle almost at top of sides (each visible from above as at the apex of a tubercle); prodeum dorsum and declivity with the transition a smoothly curve; TL 1.9-2.0 mm; light brownish yellow, head and gaster slightly darker than alitrunk - Zare 129
. . {Monomorium angustinode}angustinode .
. . Propodeum with spiracles set lower and not on tubercles; transition from dorsum to declivity a rounded angle .
. . {short description of image} fugelanum - with large eyes, 0.26-0.28 x HW, and a minute propodeal spiracle; yellow; TL 1.8 mm - Botswana 130
. . Monomorium fugelanum .
. . Eyes smaller, maximum 0.24 X HW, and propodeal spiracle small but a distinct circle .
. {short description of image} arnoldi - with relatively long scapes, SI 95-98, and small eyes, 0.20-0.22 X HW; petiole narrowly crested; glossy yellow to light brownish-yellow; TL 2.0-2.1 mm - Zimbabwe 131
. . Monomorium arnoldi .
. . Scapes relatively short, SI 87-95, and eyes 0.22-0.24 X HW .
. . {Monomorium altinode pedicel} altinode - promesonotum with 5 pairs of erect hairs; TL 1.7 mm; yellow - Congo Basin
132
. . {Monomorium altinode}altinode .
. . {short description of image} tynsorum - promesonotum with 7-8 pairs of erect hairs; TL 2.1-2.3 mm; yellow - Angola & Gabon
132
. . {Monomorium tynsorum}tynsorum .
katir-complex 4 Large eyes at least 0.30 X HW set well forward; petiole subconical in profile
. . Uniform dark brown to blackish .
. . Monomorium balathirbalathir - anterior alitrunk with 8-10 erect hairs; longest hairs on first gastral tergite longer than maximum diameter of the eye; TL 2.3 mm; glossy dark brown appendages yellow - Burkina Faso & Senegal
Senegal workers smaller than type description.
122
. . Monomorium manirmanir - anterior alitrunk with 3-4 pairs of erect hairs; longest hairs on first gastral tergite shorter than maximum diameter of the eye; TL 1.8 mm; glossy dark brown appendages lighter - Kenya & Sudan 122
. . Uniform yellow to light brownish yellow .
. . Monomorium holothirholothir - alitrunk with more than 3 pairs of erect hairs; TL 1.8-1.9 mm - Kenya 123
. . {short description of image} katir - alitrunk with one pair of erect hairs on each segment; TL 1.7-1.9 mm - Namibia 123
. . Monomorium katir .
leopoldinum-complex 6 Eyes smaller and set well forward; petiole subconical
. . Propodeal spiracle a conspicuously large circle ..
. . {short description of image} lene - head and body yellow; dorsal alitrunk with numerous erect hairs; TL 1.8-2.1 mm - Tanzania, Botswana, Zimbabwe 117
. . Monomorium lene .
. . {short description of image} borlei - head and body brown; dorsal alitrunk with only 4 pairs of erect hairs, 3 pairs being on the promesonotum; TL 1.9-2.4 mm - Congo & Angola 118
. . {Monomorium borlei}borlei .
. . {Monomorium madecassum leopoldinum} madecassum [j.syn. leopoldinum] - head and body brown; whole of head and body with many erect hairs; TL 1.9-2.4 mm - Sudan, Kenya, Zare; Madagascar 118
. . {Monomorium madecassum}madecassum .
. . Propodeal spiracle a small pinhole .
. . Anterior clypeal margin concave with projecting lateral denticles .
. . rastractum - promesonotal dorsum with 6-7 pairs of erect hairs; eye diameter max 0.27 X HW; TL 1.9 mm; yellow - KenyaMonomorium rastractum 128
. . {Monomorium springvalense}springvalense - promesonotal dorsum with 3-4 pairs of erect hairs; eye diameter max 0.21-0.23 X HW; TL 2.0-2.1 mm; alitrunk yellow, head and gaster brownish - Zimbabwe 128
. . Anterior clypeal margin near straight without projecting denticles .
. . {Monomorium pallidipes} pallidipes - TL 1.5 mm; promesonotum with 5 pairs of erect hairs; uniform brown (Bolton) plus paler appendages (Forel) - Eritrea & Tanzania 142
. . {short description of image}pallidipes .
schultzei-complex 10 Clypeal carinae sharp and close together, eyes round or near round
. . Scapes reaching or slightly surpassing occiput .
. . {Monomorium fasciatum} fasciatum - TL 1.8 mm; clear reddish yellow, gaster ochraceous with a transverse dark band - Kenya & Tanzania -status confirmed o
not in key
. . {short description of image}fasciatum .
. . {short description of image} speluncarum - scapes slightly surpass occipitum, SI 106-107; TL 1.6-1.7 mm; uniform pale yellow - Kenya & Tanzania 103
. . {Monomorium speluncarum}speluncarum
. . Scapes not reaching occiput .
. . In profile alitrunk with a very narrow metanotal suture that has only inconspicuous cross ribbing; propodeal spiracle minute .
. . {Monomorium bevisi} bevisi - promesonotum with 8 + pairs of erect hairs; dingy light brown; TL 2.4-2.6 mm - Lesotho 107
. . {short description of image} excensurae - promesonotum with 4-6 pairs of erect hairs; yellow; eyes smallish 0.20-0.23 X HW; SI 104-110; TL 1.9-2.2 mm - South Africa 108
. . Monomorium excensurae .
. . Monomorium schultzeischultzei - promesonotum with 4-6 pairs of erect hairs; yellow; eyes larger 0.24-0.27 X HW and scapes shorter SI 97-102; TL 2.0-2.2 mm - southern Africa 108
. . In profile alitrunk with a broad metanotal suture that has conspicuous cross ribbing; propodeal spiracle large and conspicuous .
. . {short description of image} kineti - propodeum with a flat to slightly concave dorsum with weakly flanged edges; TL 2.2-2.4 mm; dull yellow to brownish-yellow (dark brown, Weber) - South Sudan 109
. . {short description of image} .
. . Propodeum dorsum transversely convex or if flat without flanged borders .
. . Promesonotal dorsum with 4-6 pairs of erect hairs .
. . {short description of image} arboreum - metanotal suture shallowly impressed and only moderately broad; propodeum profile with flat area; TL 2.1-2.3 mm; dull yellow, occiput and posterior gaster darker - South Sudan & Kenya (no type photographs available)
111
. . {short description of image} crawleyi - metanotal suture unusually wide and prodeum dorsum uniformly convex; TL 2.3-2.4 mm; yellow with occiput and posterior gaster darker - Ethiopia and Congo
111
. . {Monomorium crawleyi}crawleyi .
. . Promesonotal dorsum with 8 or more pairs of erect hairs .
. . {short description of image} firmum - petiole with a conspicous anterior ventral lobe; sides of head with all hairs decumbent to appressed; TL 2.6-2.8 mm; yellow - Zimbabwe 112
. . Monomorium firmum 112
. . {short description of image} vecte - petiole with anterior ventral process a low ridge; sides of head with hairs semi-erect; TL 2.0-2.4 mm; yellow with a darker band apically on first gastral tergite - Zimbabwe & Rwanda 112
. . Monomorium vecte .
rhopalocerum-complex 5 Like schultzei-complex but eyes more elongate and scapes relatively short
. . {short description of image} termitobium binatu - scapes just surpassing the occiput, SI 100-105; TL 1.9-2.0 mm; yellow, gaster slightly darker - Zimbabwe 101
. . Scapes not reaching the occiput .
. . pacis - nomen dubum - TL1.9 mm; dull pale yellow, gaster with brown bands (close to rhopalocerum) - South Africa --
. . {short description of image} rhopalocerum - with relatively small eyes, maximum diameter 0.18-0.20 X HW; TL 2.0-2.2 mm; dull yellow, gaster may be brownish - South Africa 137
. . {Monomorium rhopalocerum} .
. . Eyes larger 0.20-0.25 X HW .
. . {Monomorium tablense} tablense - petiole with high narrow node; TL 2.1-2.2 mm; brownish-yellow to light brown - South Africa 138
. . {Monomorium tablense} .
. . {short description of image} termitobium exchao - petiole node a lower dome but still relatively narrow apically; promesonotal dorsum with 4 + pairs of erect hairs; TL 1.9-2.0 mm; uniform yellow - South Africa 140
. . {Monomorium exchao} .
. . {short description of image} symmotu - petiole with a low rounded node; promesonotal dorsum with 3 pairs of erect hairs; TL 1.8-1.9 mm; yellow - Zimbabwe 140
. . Monomorium symmotu .
strangulatum-complex 5 Sharp but well-separated clypeal carinae, without anterior teeth; scapes surpass occiput; petiole with long narrow pedicel (note M. strangulatum has 11-segmented antennae)
. . {Monomorium egens} egens - head with weakly concave occiput; promesonotum with flat dorsum and angled margins; TL 2.0-2.5 mm; brown to blackish brown - West Africa & Congo Basin 98
. . {Monomorium egens}egens .
. . Promesonotum convex and without angled margins .
. . {Monomorium gabrielense}gabrielense - West Africa & Congo Basin - pale yellow with a brownish gaster; TL 1.5-1.6 mm 103
. . {Monomorium gabrielense}gabrielense .
. . {Monomorium draxocum} draxocum - head with convex occipitum, in profile both dorsum and ventral head convex; mesopleuron with distinct reticulo-puncturation; dark brown with very pale legs; TL1.7-1.9 mm; - Cameroun to Angola
Note: Bolton (1987) felt that draxocum and noxitum might well be synonymous.
105
. . Monomorium noxitumnoxitum - legs contrast with brown body but are yellowish, gaster blackish; TL 2.0-2.1 mm - Cameroun 105
malatu-complex 5 Petiole node high, narrow or cuneate in profile, petiole with pronounced antero-ventral process - that is according to Bolton. However, the visual evidence is of a postero-ventral bulge below the petiole node.
. . {Monomorium dolatu ?} dolatu - unique to complex as having 11-segmented antennae; TL 1.4-1.5 mm; yellow, posterior of head darker and transverse dark band on first gastral tergite - West Africa - note the image is representative of specimens from Cameroun all of which have 12-segmented antennae 148
. . 12-segmented antennae .
. . Dorsum of propodeum sculptured; dark brown to blackish brown .
. . {Monomorium affabile} affabile - smaller, TL 1.5 mm; with a narrower head and proportionally longer scapes SI 88; clypeal carinae sharper - Zare 84
. . {short description of image} malatu - larger, TL 1.9-2.1 mm; with a wider head and relatively shorter scapes, SI 80-85; propodeum reticulo-punctate - Congo Basin into Uganda forests 84
. . Monomorium malatu malatu .
. . Dorsum of propodeum unsculptured; all over smooth and shiny .
. . {short description of image} disoriente - maximum diameter of eye 0.24 X HW, SI 92; TL 1.8 mm; glossy pale brown, gaster slightly darker - Tanzania 125
. . Monomorium disoriente .5
. . {Monomorium tanysum}tanysum - maximum diameter of eye 0.17-0.18 X HW, SI 86-88; TL 1.5-1.6 mm; brown with gaster darker almost blackish brown - Ghana 125
iyenasu-complex 1 Large size, small eyes, short scapes & very dense pilosity
. . Monomorium iyenasuiyenasu - TL ca 3.5 mm; yellowish-brown, occiput and apical gaster darker - Tanzania 97
boerorum-complex 15 Convenience lumping of remaining species with 12-segmented antennae
sub-complex B 6 Antennae 12-segmented; eyes reduced with a ring of ommatidia enclosing a single longitudinal row of 2-4 ommatidia; propodeal profile may be quite domed
. . Monomorium sryetumsryetum - promesonotal dorsum with only one pair of erect hairs; propodeum without erect hairs; TL 1.5 mm; vary pale yellow, gaster whitish yellow - Botswana 92
. . Promesonotal dorsum with more than one pair of erect hairs; propodeum with at least one pair of erect hairs .
. . Dorsum of head medium to blackish brown .
. . {Monomorium floricola} floricola - bicoloured, head dark brown, alitrunk lighter, usually yellow; anterior margin of clypeus with prominent median section; TL 1.7-2.0 mm - pantropical tramp 94
.
{Monomorium floricola}floricola .
. . Monomorium inquietum inquietum - head and alitrunk the same shade of brown; anterior margin of clypeus evenly convex; TL 1.7-1.8 mm - Zare 94
. . Dorsum of head pale yellow to dingy yellow .
. . Monomorium shilohenseshilohense - first gastral tergite evenly yellow; eye max diameter 0.23-0.24 X HW; TL 1.5-1.6 mm - Zimbabwe 95
. . First gastral tergite with basal half yellow, apex brown .
. . {Monomorium trake}trake - small species, TL 1.6 mm; with relatively short scapes SI 73 - Ghana 96
. . {short description of image} rotundatum - larger species, TL 1.7-2.0 mm; with relatively longer scapes SI 79-83 - Kenya, South Africa 96
.
.
Monomorium rotundatumrotundatum
.
sub-complex C 9 Antennae 12-segmented; eye with two or more median longitudinal rows; propodeal profile essentially domed; petiole quite short and in most with a narrow, blade-like subpetiolar process
. . Monomorium kelaprekelapre - propodeal spiracle with a large conspicuous circular opening; TL 1.9 mm; glossy light brown - South Africa 115
. . Propodeal spiracle with a minute circular opening .
. . {Monomorium lubricum} lubricum - anterior ventral process of petiole a large keel-like translucent lamina; TL 2.3-2.5 mm; glossy dark brown- South Africa 133
. . Subpetiolar process much less prominent .
. . Relatively large species, TL at least 1.8 mm .
. . {short description of image} boerorum - clypeus with vestigial or no carinae, anterior margin evenly and broadly convex, TL 1.9-2.0 mm; eyes 0.19-0.21 X HW; glossy dark brown - South Africa 135
. . Monomorium boerorum .
. . {short description of image} paternum - clypeus with well developed carinae and projecting centre to anterior margin; TL 2.3 mm; eyes 0.18 X HW; glossy medium to dark brown - South Africa 137
. . {Monomorium paternum} .
. . Monomorium nuptialisnuptialis - clypeus with well developed carinae and projecting centre to anterior margin; TL 1.8 mm; eyes 0.22 X HW; glossy light brown to yellowish brown - Zimbabwe 139
. . Small species TL < 1.7 mm .
. . Monomorium braunsibraunsi - promesonotum with a single pair of erect hairs at humeral angles; petiole node very low and rounded; TL 1.6 mm; uniformly yellow - South Africa 141
. . Promesonotum with 3-5 pairs of erect hairs; petiole node subconical .
. . Monomorium mavidemavide - minute with small eyes; TL 1.4-1.5 mm, eyes 0.19 x HW; head and gaster brown, alitrunk light brownish-yellow - South Africa 143
. . Monomorium torvictetorvicte - uniformly dark brown, TL 1.5-1.6 mm; SI 76-80, eye 0.20-0.21 X HW - South Africa 144
. . Monomorium musicummusicum - uniformly yellow, TL 1.6-1.7 mm; SI 81-84, eye 0.22-0.24 X HW - South Africa 144
Contents MYRMICINAE Introduction
2007, 2008, 2009, 2010, 2011, 2013, 2014, 2015 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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