Genus Messor (Forel, 1890a)

With members previously placed in Cratomyrmex Emery.

In Tribe PHEIDOLINI.

Diagnostic Features - Granivorous ants, most strongly polymorphic. Ventral surface of head with a psammaphore (a basket-like array of long, curved hairs beneath the head, used to carry sand). Mandibles strongly curved, usually dentate in smaller workers. Propodeum armed with a pair of blunt teeth. Node of petiole emarginate above in large workers.

The original genus definition, as a subgenus of Aphaenogaster, Forel (1890a: lxviii) - is at . Emery's (1892d) definition of Cratomyrmex - is at .

Described by Bolton (1973a) as restricted to the savannah regions of West Africa and also in the coastal plains. Their nests are built directly into the ground with a crater-like entrance. See also Bolton (1982) but note that he gave only HW (= head width) measurements on the grounds that other measurements have little use in diagnosis because of the often great polymorphism. The full text of Bolton's revision can be seen at - .
Messor ferreri Collingwood (1993) post-dates that review. I also have included aegyptiacus and barbarus as recorded from Sudan, Ethiopia and Somalia but extralimital to Bolton (1982)

Jean-michel Kersaudy of Nice, France, drew my attention to my mistake in citing the dimensions (from Bolton, 1982) as TL instead of HW (July 2001 email). This I have now corrected and given the approximate TL ranges from his own observations and those of Bernard, Bolton, etc. Jean-michel also kindly sent me the photograph of Messor cephalotes taken in Kenya (by Jane BURTON near Lake Nakuru, copyright Bruce Coleman Agency).

Species from Egypt, Israel, Turkey, Italy and Iran can be seen on Messor concolor, Messor ebeninus, Messor foreli, Messor meridionalis, Messor nahali, Messor niloticus, Messor rugosus, Messor structor and Messor wasmanni

Key to workers of species from sub-Saharan Africa (developed and expanded from Bolton, 1982)

¤	Questionable occurrence in sub-Saharan Africa as all early records and may be aegyptiacus - i.e. with propodeal teeth or spines; if true barbarus would lack a distinct psammophore	Ethiopia, Somalia & Sudan - barbarus
¤	Queen only - nomen nudum	Namibia - incisus
1	First gastral tergite without hairs or no more than a single posterior transverse row	2
--	First gastral tergite with hairs more or less evenly distributed over whole surface	8
2	Dorsum of propodeum with one or more pairs of standing hairs	3
--	Dorsum of propodeum without standing hairs (M. ferreri seems inconsistent)	7
3	Propodeum without any sign of teeth (note some large specimens of galla have triangular flanges at the junction of the propodeum dorsum and declivity)	4
--	Propodeum always with teeth	6
4	Petiole without a tooth at posteroventral corner; dorsum of head entirely smooth other than a rugulose mid-dorsal strip; TL 4-12 mm; red-headed, alitrunk often darker (varieties with overall darker shading)	Sahel zone and NE Africa - galla
--	Petiole with distinct tooth at posteroventral corner; scapes of major reaching to slightly exceeding occipital margin	5
5	TL 7-9 mm; head wider than long with parallel sides; petiole with distinct rugose sculpturation; dark reddish to blackish-brown, funiculi & tarsi light brown. Stitz drawing is a media worker.	.
.	Major not reported before TL ca 13 mm	Congo & Sudan - ruginodis
--	Holotype worker TL 11.2 mm; major entirely black, media (?) with reddish-head; petiole weakly sculptured, with a narrow node profile; propodeum obtusely angled	.
.	Media (?)	Kenya & Ethiopia - ferreri
--	Propodeum always with teeth	--
6	Dorsum of head with coarse dense reticulo-punctate sculpturation all over; uniform very dark blackish-brown	.
.		Niger, Mali - collingwoodi
--	TL 4-8 mm; generally ferruginous, gaster piceus; overall matt; probably without hairs on the propodeum; well developed psammophore; propodeal teeth variable but always present	Sudan & Egypt, North Africa - aegyptiacus
--	Dorsum of propodeum without standing hairs	--
7	Head wholly covered with dense longitudinal rugulae, with reticulo-punctate ground sculpturation; TL 5-8 mm; red, posterior of gaster dark brown	Southern Africa - luebberti
--	Head entirely smooth, sometimes with a short central rugulose area; TL 5-7 mm (major unknown); more generally dark	.
.		Kenya & Sudan - angularis
	First gastral tergite with hairs more or less evenly distributed over whole surface	--
8	Basal third of first gastral tergite strongly and conspicuously sculptured with rugulae, costulae, coarse reticulopuncturation, or a combination	9
--	Basal third of first gastral tergite unsculptured except for hair pits and very faint patterning	10
9	In full-face view head with lateral projecting hairs; petiole and postpetiole coarsely rugose; TL 6-12 mm; generally dark red, head lighter with anterior angles blackish; appendages and gaster dark red-brown	.
.		West Africa & Congo Basin - regalis
--	In full-face view head without lateral projecting hairs; petiole and postpetiole finely sculptured; TL 6.5-13 mm (largest major workers to 18 mm); red to reddish dark-brown, often with gaster darker than head and alitrunk	East Africa - cephalotes
10	Posterior half of clypeus with a distinct raised central step or welt	11
--	Posterior half of clypeus without a distinct raised central step or welt, usually flat or slightly concave	12
11	TL 7-11 mm; all red except gaster	Angola & Namibia - tropicorum
--	Eyes relatively large, ca 0.25 HW, in HW range 2.50 to > 4.00; TL 5.5-11 mm; slender with relatively small head; base of scape with a small tooth; more or less uniform dark brown or brownish-red, appendages lighter to yellowish; pilosity reddish	.
.	.	Southern Africa - denticornis
12	In HW range 2.80 to > 4.00 sides of head conspicuously evenly convex; propodeal profile relatively long & low	.
.	Thumbnail may be a media worker	Southern Africa - striatifrons
--	In HW range 2.80 to > 4.00 sides of head approxinmately straight; propodeal profile relatively short & high	13
13	Body pilosity very dark, deep red-brown to blackish thumbnail of probable media worker	Southern Africa - piceus
--	Body pilosity pale, white or silvery to yellowish	14
14	Head of major workers red, alitrunk and gaster much darker; TL 4.5-9 mm; head of majors one-sixth wider than long	.
.		Southeast Africa - decipiens
--	Head of major workers brown to black, more or less concolourous with alitrunk and gaster; TL 6-11 mm	.
.		Southern Africa - capensis