The Ants of Africa
Genus Tetramorium species-groups -

Part 1
Tetramorium Introduction

Species groups
Part 1 - former Triglyphothrix

Some or all erect hairs of dorsum of head or body branched (bifid, trifid or quadrifid)
Otherwise next stage of key next primary division
grebennikovi-group Small species, TL ca 2.0, without elongate simple hairs in a row on the anterior edges of the scapes or along the upper borders of the scrobes
Otherwise next stage of key next species-group
-- Head rectangular with width much less than length, CI 84; very strongly reticulo-rugose; mandibles smooth; clypeus without a raised tranverse carina; gaster with distinctive minute hair pits; TL ca 2.0 mm; dark brown, appendages golden-brown
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Tetramorium grebennikovi Tanzania - new species
ericae-group Very small to minute species (TL < 2.4 mm), all with elongate simple hairs in a row on the anterior edges of the scapes and along the upper borders of the scrobes
Otherwise next stage of key next species-group
11-segmented antennae, palp formula 3,3
02* Much reduced sculpture; TL 1.8 mm; black, tibiae yellowish-white
{Tetramorium antrema}
Tetramorium antrema Cameroun & Congo
03* Distinctly reticulo-rugose; clypeus with a raised tranverse carina; eyes with a distinctive anterior point; TL 1.6-1.9 mm; yellow-brown
{Tetramorium muscorum}
Tetramorium muscorum Pan-African forests
03* Distinctly reticulo-rugose; clypeus without a raised transverse carina; TL 1.9-2.1 mm; head with long simple hairs; gaster and postpetiole smooth & shining; black, appendages yellow-brown (Cameroun specimen shown is somewhat lighter)
Tetramorium crypticum
Tetramorium crypticum Ghana & Cameroun
12-segmented antennae, palp formula normal 4,3
12* Strongly bicoloured, head and gaster black, rest clear yellow; TL 1.7-1.9 mm
Tetramorium distinctum
Tetramorium distinctum Ghana
- Unicolourous or at most with darker gaster
10* Dorsal surfaces of head and alitrunk unsculptured other than median carina on head; TL 2.3-2.4 mm; dark blackish-brown
{Tetramorium menkaura}
. .
. . {Tetramorium menkaura} Tetramorium menkaura Ghana
13* Clypeus with a raised tranverse carina; TL 1.7-2.0 mm; dark brown, appendages lighter
{Tetramorium minimum}
. .
. {Tetramorium minimum} Tetramorium minimum West African & Congo Basin forests
15* (as paupera) Clypeus without a raised tranverse carina; TL 1.8-2.0 mm; yellow to mid-brown, gaster may be darker
Tetramorium ericae
Tetramorium ericae Zimbabwe
osiris-group Larger and gaster with dense mat of quadrifid hairs; both upper scrobe margins and leading edges of scapes with a row of elongate simple hairs
Otherwise next stage of key next species group
23* With very strong antennal scrobes and few erect long hairs; propodeum with short stout spines; petiole profile high (apex 0.65 x height); TL 3.4 mm; light yellowish-brown
{Tetramorium reptana}
Tetramorium reptana Uganda
Upper scrobe margins with obvious sngle hairs; first gastral tergite smooth but with small hair pits; petiole profile relatively low (apex 0.88 x height); TL 3.8 mm, head rectangular, CI 84; yellow-brown with slightly darker gaster
3.8{Tetramorium n sp Cameroun fk 20}
Tetramorium  nsp Cameroun fk 20 Cameroun
14* Anterior of first gastral tergite with coarse punctate sculpture; TL 3.4 mm; uniform dark brown
{Tetramorium yarthiellum}
Tetramorium yarthiellum Zambia
16* First gastral tergite smooth; distinctive narrow down-curved propodeal spines; TL 2.8-2.9 mm; brown with much darker gaster
{Tetramorium osiris}
. .
. {Tetramorium osiris} Tetramorium osiris Ghana
NA Basal segment of gaster smooth and shining; propodeal spines quite long and distinctly upturned; TL 2.2-3.0 mm; petiole node evenly but shallowly domed; variable yellowish-brown to dark brown, gaster often darker (Egypt specimen)
{Tetramorium reptana}
Tetramorium lanuginosum for comparison - sub-tropical tramp species (includes Egypt)
rothschildi-group Large species, lacking antennal scrobes; anterior clypeal margin with deep median impression
Otherwise next stage of key next species group
06* TL 3.8-4.7 mm; red-brown
{Tetramorium rothschildi}
. ./td>
. {Tetramorium rothschildi} Tetramorium rothschildi Dry southern Sahel
Ethiopia, Kenya & Ghana
inezulae-group Without long simple hairs on scapes but with a row on the upper scrobe margin; most with compressed petiole node
Otherwise next stage of key next species group
07* Uniquely, without branched hairs; alitrunk dorsum densely reticulo-punctate; TL 2.4-2.9 mm; yellow-brown
{Tetramorium arnoldi}
Tetramorium arnoldi Zimbabwe
10* Without propodeal spines; TL 2.4 mm; dorsum of head and alitrunk rugulose; clear ferruginous brown
{Tetramorium imbelle}
. .
. {Tetramorium imbelle} Tetramorium imbelle Ethiopia
TL max 3.3 mm . . .
22* Yellow or light yellow-brown; TL 1.8-2.1 mm; CI 89-95; dorsal alitrunk finely rugo-reticulate;
{Tetramorium gestroi}
. .
. {Tetramorium gestroi} Tetramorium gestroi Southern area of wet forests
Angola, Gabon and Uganda
Dark brown to black . . .
22* TL 2.2-2.5 mm; CI 90-96; base of gaster smooth; eyes small; antennal scrobe with strong longitudinal median carina; dorsal alitrunk longitudinally rugose; black to blackish-brown
{Tetramorium furtivum}
. .
. {Tetramorium furtivum} Tetramorium furtivum Wet western forests
Angola to Ghana
20* Base of gaster densely punctate; antennal scrobe with weak median longitudinal carina, lower portion of scrobe sculptured above the eye; mandibles striate; TL 2.2-2.3 mm, CI 86-92; dark brown
Tetramorium trimeni
Tetramorium trimeni South Africa
20* Base of gaster densely punctate; antennal scrobe with strong longitudinal median carina; TL 2.5-3.3 mm, CI 90-97; medium to dark brown
{Tetramorium inezulae}
. .
. {Tetramorium inezulae} Tetramorium inezulae East Africa
includes eastern Zare
(17*) Worker not known - may be sexuals of inezulae Tetramorium desertorum Botswana
TL at least 3.4 mm . . .
17* Eyes minute, diameter less than width of scape; TL 3.4-3.7 mm; mandibles striate; sculpturation rugulose and weakly longitudinal; yellow to yellow-brown
{Tetramorium microps}
. .
. {Tetramorium microps} Tetramorium microps Southern Africa
19* First gastral tergite with only simple hairs; TL 3.6-3.8 mm; pale yellow-brown
{Tetramorium talpa}
Tetramorium talpa Eastern Zare
21* Large species TL 3.6-3.8 mm; brown, gaster usually darker
{Tetramorium tenebrosa}
. .
. {Tetramorium tenebrosa} Tetramorium tenebrosum Mozambique & Kenya
gabonense-group Stocky with overall covering of branched trifid or quadrifid hairs
- Without antennal scrobes
05* Propodeum unarmed; TL 3.5 mm; brown
{Tetramorium agnum}
. .
. {Tetramorium agnum} Tetramorium agnum Zare & Congo
06* Propodeum with short teeth; TL 2.7-3.6 mm; dark brown
{Tetramorium eminii}
. .
. {Tetramorium eminii} Tetramorium eminii Pan-African
- With well developed antennal scrobes
23* Propodeum unarmed; minute TL 2.3 mm; uniform light brown
{Tetramorium dedefra}
. .
. {Tetramorium dedefra} Tetramorium dedefra Angola & Uganda
- Propodeum with spines or acute teeth
24* Bicoloured, head bright golden-yellow, rest blackish-brown; TL 2.7 mm
{Tetramorium pulcherrimum}
. .
, {Tetramorium pulcherrimum} Tetramorium pulcherrimum Forests of western Uganda & eastern Zare
- Unicolourous; head and/or gaster may be darker than alitrunk
- Branched hairs on dorsal surfaces all appressed, lying flat . .
26* {Tetramorium sericeum}TL 2.3-2.8 mm, CI 93-97; gaster with basal band of punctate sculpture; originally described as piceous, almost black, legs, antennae and mandibles dark ochreous Tetramorium sericeum Zimbabwe
new {Tetramorium n sp Congo 2008}TL 2.4 mm, CI 91; head slightly squarer; branched hairs coarser and, particularly on the gaster, distinctly bifid, arranged in distinctive angled lines;  gaster without obvious sculpturation; uniform dark brown; Tetramorium (Trig.) n. sp. Congo 2008 Congo
- Branched hairs on dorsal surfaces at least sub-erect . .
30* TL 2.4 mm; mandibles smooth & shining; mid-brown, legs lighter, yellow brown
Tetramorium thoth
Tetramorium thoth South Africa
TL > 3.0 mm . . .
With long propodeal spines . . .
27* Petiole from above strongly crescent shaped; TL 4.0 mm; dark brown
{Tetramorium monardi}
. {Tetramorium monardi} Tetramorium monardi Cameroun & Angola
32* Clypeus with weak or incomplete median carina; postpetiole with little or no sculpturation; TL 3.8-4.6 mm
{Tetramorium gabonense}
. .
. {Tetramorium gabonense} Tetramorium gabonense Wet forests of Cameroun east to Central Africa
32* Clypeus with strong median carina; postpetiole strongly sculptured; TL 3.0-3.6 mm; uniform mid-brown
{Tetramorium constanciae}
. .
. {Tetramorium constanciae} Tetramorium constanciae East Africa
With reduced propodeal spines . . .
29* Head convex in front view; lower portion of antennal scrobe densely reticulo-rugose; TL 3.4 mm
{Tetramorium baufra}
. .
. {Tetramorium baufra} Tetramorium baufra Zimbabwe
31* Petiole node from above with convex anterior face; TL 3.2-3.9 mm; variable brown
{Tetramorium brevispinosum}
. .
. {Tetramorium brevispinosum} Tetramorium brevispinosum Wet forests of West & Central Africa
(as silvestrii)
Petiole node from above with flat anterior face; smaller TL 3.1 mm
{Tetramorium surrogatum}
. .
. {Tetramorium surrogatum} Tetramorium surrogatum Ethiopia
return to start of key stage
2007, 2008, 2009, 2010, 2011, 2013 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.