The Ants of Africa
Genus Tetramorium species-groups - Part 2
Tetramorium Introduction

Species groups
Part 2 - former Xiphomyrmex

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Species in the T. weitzeckeri species group of Hita Garcia et al (2010c). Kindly sent to me by Francisco Hita Garcia (November 2010).
Garcia, F. H., Fischer, G. & Peters, M. K. 2010c. Taxonomy of the Tetramorium weitzeckeri species group (Hymenoptera: Formicidae) in the Afrotropical zoogeographical region. Zootaxa, 2704:, 1-90. source pdf (purchase only) * = new species in Garcia et al.

Tetramorium edouardi complex - petiole node always high nodiform

Tetramorium muralti complex - antennal scrobe well developed and deep with a distinct margin all round

Tetramorium weitzeckeri complex - well developed sculpturation on head, at least seven rugae between frontal carinae

Most with simple erect hairs, a few with bizarre pilosity or without erect hairs, none with multifid hairs Tetramorium s.s.
11-segmented antennae (Xiphomyrmex) {11-segmented antenna}
Otherwise next stage of key next primary division
weitzeckeri-group Petiole squamiform or at least a high narrow node in profile
Otherwise next stage of key next species group
. Scrobes no more than weakly developed next stage of key
Complex-A Mandibles unsculptured, well developed scrobes - muralti complex
03 Strongly bicoloured, head & gaster black, alitrunk & appendages clear pale yellow; TL 2.1-2.3 mm
{Tetramorium flavithorax}
. .
. {Tetramorium flavithorax} Tetramorium flavithorax West Africa
. Unicolourous . .
. Alitrunk dorsum with 3-7 well developed longitudinal rugae . .
NA Antennal scape short (SI 65–70); petiolar node squamiform, strongly transverse and thin, in dorsal view between 2.5 to 3 times wider than long (DPeI 257–300); dorsum of mesosoma usually with 3, rarely 4, strong longitudinal rugae medially
Tetramorium trirugosum
Tetramorium trirugosum Cameroun & Gabon
NA Antennal scape of moderate size (SI 74–81); petiolar node thickly squamiform, in dorsal view either less than twice as wide as long or only faintly more (DPeI 179–211); dorsum of mesosoma with 6 or more longitudinal rugae
{Tetramorium intermedium}
Tetramorium intermedium Ghana
. Alitrunk dorsum with no more than weak partial longitudinal rugae
. .
. Anterior margin of clypeus uninterrupted and convex . .
05 Head with three long frontal carinae, frontal carinae continuing right around to form a posterior margin to the antennal scrobe; TL 2.1-2.3 mm; uniform blackish-brown (the queen has a wider postpetiole than the worker)
Tetramorium muralti
Tetramorium muralti West Africa & Congo Basin
NA Head with only median frontal carina running to occiput; TL 2.3-3.3 mm; uniform dark brown to black . .
. {Tetramorium susannae} Tetramorium susannae West Africa & Congo Basin
. Anterior margin of clypeus with a distinct median impression . .
NA Metanotal groove impressed(Fig. 8A); postpetiole in lateral view strongly rounded dorsally and relatively low, only 1.25 times higher than long (LPpI 77–83), in dorsal view usually less than 1.5 times wider than long (DPpI 143– 151)
Tetramorium kakamega
Tetramorium kakamega Kenya
05 Petiolar node moderately squamiform, in dorsal view distinctly above twice as wide as long (DPeI 225- 268); in Akengi, X.1913, leg. H.O Lang (MCZ, USNM) Akengi, X.1913, leg. H.O Lang (MCZ, USNM) lateral view between 2.3 to 2.8 times higher than long (LPeI 36–44); colour uniformly very dark brown to black
{Tetramorium occidentale}
. .
. {Tetramorium occidentale} Tetramorium occidentale West Africa & Congo Basin
NA Petiolar node thickly squamiform, in dorsal view less than twice as wide as long (DPeI 188–196); in lateral view weakly above twice as high as long (LPeI 47–50); colour uniformly reddish brown to brown
Tetramorium akengense
Tetramorium akengense D.R. Congo

Complex-C Well developed sculpturation on head, at least seven rugae between frontal carinae - weitzeckeri complex
- No pilosity on first gastral tergite
16 Alitrunk with numerous erect hairs; TL 3.4-3.6 mm; uniform brown
Tetramorium sepultum
Tetramorium sepultum S. Africa & Swaziland
- Alitrunk dorsum with few or no erect hairs
NA Alitrunk dorsum with distinct reticulo-punctate ground sculpturation
. .
. {Tetramorium bendai} Tetramorium bendai Burundi
NA Most of alitrunk dorsum longitudinally rugose but lacking distinct ground sculpturation
Tetramorium tanaense
Tetramorium tanaense Kenya
16 Alitrunk dorsum with almost no sculpturation; TL 3.4-4.1 mm; light to dark brown
{Tetramorium humbloti}
. .
. {Tetramorium humbloti} Tetramorium humbloti East & southern Africa
- Pilosity on first gastral tergite
19 Dorsum of head with conspicuous reticulate-punctate groundsculpturation; propodealspines always long to very long (PSLI 28- 43)
Postpetiole profile rounded nodiform; TL 2.9-3.7 mm; head with reticulo-punctate ground sculpture between longitudinal rugae; deep reddish brown to brown, gaster darker
{Tetramorium guineense}
. .
. {Tetramorium guineense} Tetramorium guineense West Africa & Congo Basin
. Dorsum of head without conspicuous reticulo-punctate ground sculpturation. . .
NA Distinctly bicoloured; head and alitrunk orange to reddish-brown; pedicel and gaster very dark brown to black
{Tetramorium snellingi}
Tetramorium snellingi CAR, Kenya, Uganda
NA generally bicoloured with alitrunk and pedicel
 {Tetramorium renae}
Tetramorium renae So Tom & Principe
19 (part) Both segments of pedicel narrow squamate; TL 3.0-4.1 mm; head smooth and shiny between longitudinal rugae; brown to blackish-brown, gaster darker
{Tetramorium weitzeckeri}
Bolton determined specimen .
. {Tetramorium weitzeckeri} Tetramorium weitzeckeri Eastern & southern Africa
NA Smaller species (HW 0.644–0.744, HL 0.678–0.761, SL 0.467–0.539, WL 0.778–0.911); propodeal spines moderate to long, triangular-elongate to spinose, but never as long as above (PSLI 23- 29); rain forest species
Tetramorium boltoni
Tetramorium boltoni West Africa & Congo Basin (into East Africa forests)

Complex-B1 Antennal scrobe no more than weakly developed and shallow petiole node high and nodiform - edouardi complex
NA Alitrunk, petiole, postpetiole, and first gastral tergite without standing hairs
{Tetramorium mkomazi - copyright prevented}
Tetramorium mkomazi Tanzania
- All erect hairs simple
- Eyes relatively small (OI 21-22), bicoloured with gaster distinctly darker than rest
07 TL 3.7 mm; orange-brown, gaster much darker; mandibles smooth and shiny
{Tetramorium schoutedeni}
. .
. TL 3.7 mm; orange-brown, gaster much darker; mandibles smooth and shiny
{Tetramorium schoutedeni}
Tetramorium schoutedeni Zare
NA Mandibles with at least fine longitudinal striations
{Tetramorium philippwagneri}
Tetramorium philippwagneri Cameroun, Gabon & Zambia
- Eyes relatively large, uniformly coloured
NA Median area of clypeus unsculptured, smooth and shiny
{Tetramorium robertsoni}
Tetramorium robertsoni Tanzania
23 Clypeus with distinct median longitudinal ruga and 1 or 2 additional lateral rugae on each side
Antennal scapes shorter (SI 76–83); eyes larger (OI 26–30); head relatively shorter (CI 90–95); in profile metanotal groove distinctly impressed; usually of very dark brown to nearly black colour
{Tetramorium edouardi}
. .
. {Tetramorium edouardi} Tetramorium edouardi Burundi, D.R. Congo, Ethiopia, Kenya, Tanzania, Uganda
NA Clypeus with distinct median longitudinal ruga and 1 or 2 additional lateral rugae on each side; antennal scapes larger (SI 85–92); eyes smaller (OI 23–26); head relatively longer (CI 87–91); in profile metanotal groove not impressed; coloration reddish brown
{Tetramorium rubrum}
Tetramorium rubrum Ivory Coast, Ghana, Nigeria & Cameroun
Complex-B2 Striate mandibles, high narrow petiole node
- Pilosity variably bizarre (i.e. not simple and relatively slender)
17 Unique and bizarre pilosity: TL 3.4 mm; orange-brown, gaster blackish-brown
{Tetramorium pinniphilum}
. .
. {Tetramorium pinniphilum} Tetramorium pinnipilum Angola & Kenya
21 First gastral tergite with dorsoventrally flattened and reclinate hairs: TL 3.4-3.8 mm; medium to dark-brown
{Tetramorium zonacaciae}
. .
. .
{Tetramorium zonacaciae}
Tetramorium zonacaciae Cameroun across to East African forests
22 With distinctive clavate hairs; TL 3.6 mm; uniform mid-brown
{Tetramorium rogatum}
. .
. {Tetramorium rogatum} Tetramorium rogatum Angola
tortuosum-group Petiole strongly nodiform; dorsal or outer surface of hind tibiae with long projecting hairs
Otherwise next stage of key next species group
NA Antennal scapes relatively short (SI 73 - 77); petiolar node in profile clearly rectangular nodiform with anterodorsal and posterodorsal margins at about same height
{Tetramorium hecate}
Tetramorium hecate Cameroun & Gabon
20 SI 80-86; mandibles coarsely striate; eyes smaller 0.23 X HW; petiole long, it and postpetiole sculptured; TL 3.7-4.2 mm; generally black, head reddish
{Tetramorium capillosume}
. .
. {Tetramorium capillosume} Tetramorium capillosum Gabon
10 SI 80-86; mandibles unsculptured; eyes about 0.27 X HW; pedicel unsculptured; TL 2.8 mm; head and body bright orange-brown, gaster blackish-brown
{Tetramorium tabarum}
. .
. {Tetramorium tabarum} Tetramorium tabarum Zare & Cameroun
angulinode-group Petiole strongly nodiform; dorsal surface of hind tibiae only with fine pubescence; gaster with hairs in first tergite directed towards midline
09 Base of first gastral tergite densely sculptured; TL 3.1-3.3 mm; dark brown, gaster darker
Tetramorium legone
Tetramorium legone Ghana & Nigeria savannah
nests in sandy soil
- Base of first gastral tergite unsculptured
11 Alitrunk dorsum with dense coarse puncturate sculpture and a dull surface; TL 3.5-3.7 mm; dark brown, gaster black - note others matching the general features are orange brown with a darker gaster
{Tetramorium calinum}
. .
. {Tetramorium calinum} Tetramorium calinum Ghana & Nigeria
savannah/open forest
nests in sandy soil
- Alitrunk dorsum with rugulose sculpturation and a shiny surface
12 Propodeal spines short; promesonotum only lightly rugose; pedicel dorsum completely smooth and shiny; TL 2.1-2.3 mm; uniform blackish-brown to black
{Tetramorium minisculum}
. .
. {Tetramorium minisculum} Tetramorium minisculum West Africa & Congo Basin
- Propodeal spines long
14 Postpetiole node much shorter than that of petiole; postpetiole node smooth; TL 2.2-2.6 mm
{Tetramorium chloe}
. .
. {Tetramorium chloe} Tetramorium chloe Zimbabwe
- Petiole and postpetiole nodes about the same length
- TL no more than 2.4 mm
(14) Without any propodeal armature; postpetiole and petiole nodes about equal length; postpetiole node faintly sculptured; TL 2.4 mm; mid-brown, gaster blackish
Tetramorium nullispinum
Tetramorium nullispinum Nigeria
(14) TL 2.3 mm; propodeal spines long, acute and straight in profile; pedicel nodes reticulate-punctate; overall shiny, ferruginous, dorsum of head and gaster dull (apparently very similar to angulinode)
{Tetramorium sudanense}
Tetramorium sudanense South Sudan
- TL at least 2.4 mm
- NOTE - the diagnosis from here is confused due to an apparent mix up by Bolton (1980). Bolton described a new species T. zapyrum that appears to match the original Santschi (1910c) description of T. angulinode. As Bolton did not illustrate his zapyrum and made no explicit reference to Santschi's clear drawings of angulinode, this is difficult to unravel. it seems quite possible that zapyrum should be relegated to a junior synonym of the type angulinode. The form illustrated by Bolton appears better matched to what I separate as T. angulinode papyri.
14 (13 zapyrum) TL 2.3-2.9 mm, HL 0.75, HW 0.65, CI 87, SL 0.42, SI 65, PW 0.58; petiole node in profile cuboid with a (near) flat dorsum and vertical anterior and posterior faces, without any diagonal carina; postpetiole and petiole nodes about equal length; postpetiole node sculptured; with quite dense and very fine erect hairs; legs and antennae with decumbent quite strong pubescence; dark brown; savannah and cleared forest
{Tetramorium angulinode pedicel}
Santschi (1910c) type form (matched by Bolton description of Tetramorium zapyrum) .
. {Tetramorium angulinode type form} Tetramorium angulinode Panafrican
- Pedicel segments weakly sculptured with shining spaces
(14) TL 2.4 mm; both pedicel nodes with a shallowly convex dorsum in profile, the petiole with a distinct diagonal carina from upper anterior to lower posterior corners; postpetiole and petiole nodes quite weakly sculptured with smooth areas; hind tibiae quite short and broad; legs and antennae with minute pubescence; savannah and cleared forest
{Tetramorium angulinode Bolton form}
. .
. {Tetramorium angulinode papyri} Tetramorium angulinode papyri West Africa & Congo Basin
13 TL 2.7-3.2 mm, CI 100; petiole weakly sculptured but with clear longitudinal rugae; postpetiole slightly narrower then the petiole in profile but much wider when viewed from above, it also has distinctly angular lower corners; hind tibiae relatively short and broad dark brown, gaster blackish; forest species, nests in wood on the ground
{Tetramorium nsp Congo}
. .
. {Tetramorium zapyrum} Tetramorium rugosum Nigeria & Congo Basin - new species
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2007, 2008, 2011, 2013, 2014, 2016 - Brian Taylor CBiol FRSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.