Tetramorium camerunense species group

Based on Bolton 1980.

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Diagnosis
Bolton (1980) Antennae with 12 segments. Sting appendage triangular. dentiform or pennant-shaped. Mandibles generally smooth and shining, less commonly delicately striate. Anterior clypeal margin with a median notch or impression. usually inconspicuous or shallow but absent in only one species (amissum). Frontal carinae long and fine. reaching beyond level of posterior margins of eyes. sometimes approaching occipital margin. Antennal scapes relatively short, Sl < 90. Scrobes very poorly developed, at most a shallow impression in the sides below the frontal carinae: commonly vcstigial. With head in full-face view the sides convex. The head not roughly rectangular in outline. Propodeum with a pair of spines which though narrow and short in some species, are always longer than the metapleural lobes. Clypeus with three carinae (median and a flanking pair), generally without other sculpture. Dorsum of head finely longitudinally rugulose, without cross-meshes and never having an occipital rugoreticulum. Pedicel segments unsculptured or only with faint sculpture in camerunense-complex; one or both segments strongly sculptured inlucayanum-complex. All dorsal surfaces of head and body with numerous standing hairs but dorsal (outer) surfaces of hind tibia with decumbent to appressed pubescence only, except in amissum and tychadion where predominantly suberect pubescence is present.

The 12 species currently known in this group fall into two dissimilar-sized complexes which may have had independent origins and come to resemble one another by convergence. The first of these. the lucayanum-complex contains four species (amissum, lucayanum, tycchadion, and versiculum) characterized by having the pedicel segments sculptured, usually strongly so, and by having the mandibles striate. Of these four amissum and tycchadion have the dorsal (outer) surface of the hind tibiae with standing pubescence, and amissum is unique in the group in that it does not have a notched anterior clypeal margin.

The remaining eight species are placed in the camerunense-complex, containing browni, camerunense, gegaimi, hapale, ictidum, luteipes, miserabile and ubangense. and are characterized by having the pedicel segments unsculptured or nearly so, and by having the mandibles smooth and shining (except in ''lutipes'). For convenience the complex can be further divided by colour, as camerunense, hapale, ictidum and ubangense. are uniformly dark brown or black everywhere, whereas the other four are partially (head plus alitrunk) or entirely yellowish or light yellow-brown. All members of the group are fairly uncommon and colleclions if them usually consist of only one or two workers in each series. Several are known only from a single series and some from only a single worker. Despite this paucity of material the group is known to be very widespread in Africa and it is possible that the species described here represent a remnant of a once more successful group which has now been pushed into the background by newly developed groups.

Hita-Garcia et al. 2010 repeated Bolton's (1980) diagnosis in a bulleted form:

1. antennae 12-segmented

2. antennal scape relatively small to moderate (SI < 90)

3. anterior clypeal margin generally with small median impression (absent in one species)

4. frontal carinae long and fine, generally reaching posterior eye margin, sometimes running to occipital margin

5. antennal scrobe weakly developed

6. propodeal spines of varying length, but always longer than propodeal lobes

7. mandibles generally smooth and shining, rarely finely striate

8. clypeus with three longitudinal rugae

9. cephalic dorsum usually finely longitudinally rugulose, without cross-meshes; occipital rugoreticulum never developed

10. all dorsal body surfaces with numerous standing hairs

11. dorsal surfaces of hind tibiae generally with decumbent to appressed pubescence only, in two species suberect

12. sting appendage triangular, dentiform or pennant-shaped Prior to this study, the T. camerunense species group contained 12 species that were subdivided into two species complexes based on differences in sculpturation (Bolton 1980). The T. lucayanum complex, containing four species, can be characterized by the presence of sculptured mandibles, petiole and postpetiole. One or both of the waist segments are generally strongly sculptured. The other and larger complex, the T. camerunense complex with eight species, possesses typically unsculptured waist segments and mandibles.