Tetramorium metactum

Most commonly encountered in rainforest, T. metactum is also known from other wet forest habitats. Many collections have been from sweeping vegetation and litter sampling.

Identification
Bolton (1980) - Described from a short series intercepted at quarantine in New York, T. metactum is most closely related to Tetramorium youngi from Angola. Details of the separation of the two species are given under T. youngi.

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Central African Republic, Democratic Republic of Congo, Gabon, Kenya, Uganda.

Nomenclature

 *  metactum. Tetramorium metactum Bolton, 1980: 280, figs. 54, 57 (w.) KENYA.

Worker
Holotype: TL 4.0, HL 0.86, HW 0.70, CI 81, SL 0.78, SI 111, PW 0.59, AL 1.10. Paratypes (3 measured): TL 3.6-4.1, HL 0.82-0.84, HW 0.66-0.69, CI 80-83, SL 0.74-0.78, SI 111-113, PW 0.52-0.57, AL 1.02-1.08. Maximum diameter of eye 0.19-0.20, about 0.27-0.29 x HW.

Mandibles coarsely longitudinally striate. Anterior clypeal margin entire, without a median notch or impression. Median portion of clypeus with more than three longitudinal carinae or rugulae (5 in holotype, 4-5 in paratypes). Frontal carinae long, reaching back almost to occipital margin, slightly more strongly developed than other cephalic sculpture throughout their length. Antennal scrobes shallow and narrow, feebly developed. Antennal scapes with SI > 100. Maximum diameter of eye 0.20, about 0.28 x HW. Alitrunk in profile with metanotal groove impressed. Propodeal spines very long, narrow and acute apically, slightly downcurved along their length. Metapleural lobes short-triangular, blunted apically, not acute and upcurved. Petiole in profile with an elongate anterior peduncle, the antero- and posterodorsal angles of the node blunt and rounded, the latter more rounded than the former. Dorsal surface of node evenly but shallowly convex. Anterior and dorsal faces of postpetiole node confluent in a single smooth curve, rounding behind into a much more steeply sloping, almost vertical posterior face. In dorsal view the petiole node slightly longer than broad, the postpetiole about as long as broad, but much broader behind than in front. Dorsum of head with 7 (5-7 in paratypes) irregular longitudinal rugulae between the frontal carinae at the level of the eyes. Scattered cross-meshes are present between the rugulae; occipital region with a narrow rugoreticulum. Ground-sculpture of head a weak but fairly conspicuous granulation or punctulation. Dorsal alitrunk irregularly rugose but the rugae predominantly longitudinal on the pronotum. Dorsum and sides of petiole with faint rugular traces. Postpetiole smooth and shining, with the faintest vestige of punctulate sculpture low down on the sides. First gastral tergite smooth and shining. All dorsal surfaces of head and body with numerous standing hairs; the scapes and tibiae with short, fine, decumbent to appressed pubescence. Colour dark brown, the appendages yellow.

Paratypes: As holotype except for variation noted in the description.

Type Material
Holotype worker, Kenya: (no loc.) on orchids intercepted at New York quarantine, 1.vi.1961 (W. L. Brown). Paratypes. 3 workers with same data as holotype (MCZ; ).

References based on Global Ant Biodiversity Informatics

 * Ross S. R. P. J., F. Hita Garcia, G. Fischer, and M. K. Peters. 2018. Selective logging intensity in an East African rain forest predicts reductions in ant diversity. Biotropica 1-11.