Tetramorium longicorne

Tetramorium longicorne is widely distributed in woodland, savannah and open grassland zones of the Ethiopian region but appears to be relatively uncommon (Bolton 1980).

Identification
Bolton (1980) - A very conspicuous species in this group, longicorne is easily identified by its lack of hair on the alitrunk, large eyes, broad clypeus, strong frontal carinae and mandibles which are not strongly longitudinally striate. It is not obviously closely related to any other member of the group and must be regarded as a distinct offshoot, occupying a complex of its own, as discussed under the species-group heading.

Distribution based on Regional Taxon Lists
Afrotropical Region: Burkina Faso, Cameroun, Kenya, Mozambique, Nigeria, South Africa, United Republic of Tanzania, Zimbabwe.

Biology
A soil nesting species. Field notes from Hamish Robertson:

SAM-HYM-C008695 - Field # 57. Nest entrance in open gravel surface at camp. Nest entrance c12mm in diameter, tunnel going down vertically. Superficial excavation.. Habitat: woodland:_open. Nest site: ground: underground.

SAM-HYM-C009307 - Open woodland. Nest in soil, entrance in open ground, 30x23 mm wide. Entrance surrounded by shallow crater of soil. Saw harvester termite walk over edge of crater and then get dragged by single worker until together they fell down hole. Is the wide entrance acting as a pitfall trap? Field # 99.. Method: saw nest/nest entrance. Habitat: woodland:_open. Nest site: g round: underground.

Also specimens found: Burnt slope, pitfall traps; Open woodland on slope, light trap; Lightly wooded on red laterite soil, pitfall traps. Dominant trees Acacia senegal & A. nilotica.

Nomenclature

 *  longicorne. Tetramorium longicorne Forel, 1907a: 13 (w.) KENYA. See also: Bolton, 1980: 328.

Worker
Bolton (1980) - TL 4.4-5.1, HL 0.98-1.14, HW 0.86-1.00, CI 85-89, SL 0.96-1.10, SI 110-120, PW 0.62-0.78, AL 1.28-1.42 (20 measured).

Mandibles usually densely punctulate-shagreened, sometimes also with some delicate longitudinal striation. Median portion of clypeus broad, sloping, transversely and longitudinally more or less flat in its anterior half. Anterior clypeal margin convex and entire, with an anterior apron which projects over the basal mandibular denticle. Median clypeal carina not developed, the broad expanse of the clypeus traversed by a few weak rugulae, all of which are about equally strongly developed. Frontal carinae running back to the level of the posterior margins of the eyes or just beyond it, strongly developed and distinctly raised above the surrounding areas so that the space between them forms a raised platform, especially anteriorly. Antennal scrobes absent. Scapes long, SI > 100 (SL usually approximately equal to HL). Eyes large, maximum diameter 0.27-0.32, about 0.30-0.33 x HW. Anterior pronotum with a strong but blunt transverse crest separating the dorsum from the anterior declivity. Propodeum armed with a pair of long, strong spines which are much longer than the low, bluntly triangular metapleural lobes. Petiole in profile with an elongate, fairly stout peduncle and a node which is roughly square, although the antero- and posterodorsal angles tend to be blunt. Postpetiole in profile with the sternite produced into a blunt ventral process. Petiole node in dorsal view usually broader than long, rarely about as broad as long. Dorsum of head longitudinally rugose between the frontal carinae, but occiput and sides of head between eye and frontal carinae reticulate-rugose. Ground-sculpture between the rugae everywhere of fine punctulation or dense shagreening so that the surfaces have a rough appearance. Dorsal alitrunk rugose, usually strongly so, the rugae predominantly longitudinal and strongest on the pronotum, but often irregular, meandering or with some cross-meshes. Ground-sculpture as on head. Dorsal surfaces of petiole and postpetiole finely, densely and generally irregularly rugulose, although on the postpetiole the rugulae may be mostly longitudinal. Spaces between rugulae packed with punctulate or granular ground-sculpture. Gastral sculpture variable in extent and intensity but at least the basal third of the first tergite (usually more) with dense longitudinal striae or costulate, the spaces between which are filled with fine punctulation. This sculpture always strongest basally, becoming fainter posteriorly on the sclerite. Pilosity very reduced, consisting only of a few scattered very short hairs on the dorsal head and first gastral tergite and sometimes a few similar hairs on the pedicel segments. Sparse longer hairs are present on the remaining gastral segments behind the first but hairs are completely absent from the dorsal alitrunk and the sides of the head. Scapes and tibiae have short appressed pubescence. Colour dull red, the gaster darker.

Type Material
Bolton (1980) - Holotype worker, Kenya: Mto-ya-kifaru (Katona) [examined].

References based on Global Ant Biodiversity Informatics

 * Bolton B. 1980. The ant tribe Tetramoriini (Hymenoptera: Formicidae). The genus Tetramorium Mayr in the Ethiopian zoogeographical region. Bulletin of the British Museum (Natural History). Entomology 40: 193-384.
 * Garcia F.H., Wiesel E. and Fischer G. 2013.The Ants of Kenya (Hymenoptera: Formicidae)Faunal Overview, First Species Checklist, Bibliography, Accounts for All Genera, and Discussion on Taxonomy and Zoogeography. Journal of East African Natural History, 101(2): 127-222
 * IZIKO South Africa Museum Collection