Tetramorium sepultum

Tetramorium sepultum seems is a rare Southern African species known from but a few collections.

Identification
Tetramorium sepultum can be best distinguished from the rest of the species complex by the following characters: propodeal spines medium sized and thick (PSLI 22 - 23); relatively small eyes (OI 21 -22); dorsum of mesosoma longitudinally rugose without distinct ground sculpturation; first gastral tergite without standing hairs.

A member of the Afrotropical weitzeckeri species complex, which is part of the weitzeckeri species group.

Key to weitzeckeri-group species.

Distribution
Known from South Africa, Mozambique and Swaziland.

Distribution based on Regional Taxon Lists
Afrotropical Region: Mozambique, Swaziland.

Nomenclature

 *  sepultum. Tetramorium sepultum Bolton, 1980: 232 (w.) SWAZILAND. See also: Hita Garcia, Fischer & Peters, 2010b: 78.

Hita Garcia et al. (2010) - In terms of morphological similarities Tetramorium sepultum can be set together with Tetramorium bendai, Tetramorium humbloti, and Tetramorium tanaense. All four share the absence of standing hairs on the first gastral tergite that separates them from Tetramorium boltoni, Tetramorium guineense, Tetramorium renae, Tetramorium snellingi, and Tetramorium weitzeckeri. However, T. bendai with its conspicuous and dense reticulate-punctate ground sculpturation on the mesosoma differs strongly from T. sepultum which shows no distinct ground sculpturation there. The latter also possesses a less transverse postpetiole (DPpI 194 - 200) than T. bendai (DPpI 206 - 239). Additionally, T. humbloti can be well separated from T. sepultum since the mesosomal, especially the pronotal, dorsum in the first is generally smooth and shiny whereas it is longitudinally rugose in the latter. The mesosomal dorsum of T. tanaense is longitudinally rugulose, but the eyes of this species are larger (OI 26 - 29) and the propodeal spines longer (PSLI 34 - 37) than in T. sepultum (OI 21 - 22, PSLI 22 - 23). In addition, the latter possesses much more standing hairs on the dorsum of mesosoma (usually 14 or more) than T. tanaense (8 at most).

Description
Hita Garcia et al. (2010) - HL 0.789 - 0.811; HW 0.767 - 0.789; SL 0.622 - 0.644; EL 0.167 - 0.172; PW 0.578 - 0.589; WL 0.933 - 0.989; PSL 0.178; PTL 0.122 - 0.128; PTH 0.356 - 0.361; PTW 0.317 - 0.344; PPL 0.200 - 0.206; PPH 0.378 - 0.383; PPW 0.389 - 0.411; CI 97; SI 81 - 82; OI 21 -22; PSLI 22 - 23; PeNI 55 - 58; LPeI 34 -36; DPeI 259 - 270; PpNI 67 - 70; LPpI 52- 54; DPpI 194 - 200; PPI 119 - 122 (2 measured).

Head slightly longer than wide (CI 97). Anterior clypeal margin with weak but distinct median impression. Frontal carinae strongly developed, ending distinctly before posterior margin of head. Antennal scrobe narrow, shallow, without differentiated ventral margin, not reaching posterior margin of head. Antennal scape of medium length, not reaching posterior margin of head (SI 81 - 82). Eyes relatively small (OI 21 - 22), with 8 to 9 ommatidia in longest row. Metanotal groove weakly impressed. Propodeal spines of medium size and relatively thick (PSLI 22 - 23). Propodeal lobes small, triangular and acute. Node of petiole squamiform, in dorsal view transverse, more than 2.5 times wider than long (DPeI 259 - 270), in lateral view around 2.8 to 3 times higher than long (LPeI 34 - 36). Postpetiole thickly squamiform, in dorsal view around 2 times wider than long (DPpI 194 - 200); in lateral view thicker than petiolar node, around 1.8 to 1.9 times higher than long (LPpI 52 - 54). Mandibles finely longitudinally striate. Clypeus with mostly longitudinal rugae, stronger median carina present. Head with mostly longitudinal rugulation, dorsum of head with 8 to 10 widely spaced rugae between frontal carinae, often running to posterior margin of head. Spaces between dorsal rugae and scrobal area moderately reticulate-punctate. Mesosoma dorsally and laterally distinctly rugose, mostly longitudinally, spaces between rugae and propodeal declivity smooth and shiny. Both waist segments and gaster completely unsculptured, smooth and shiny. Head and mesosoma with numerous fine, long, erect hairs (14 to 16 on dorsum of mesosoma); petiole and postpetiole usually with 1 or 2 pairs each. First gastral tergite always without standing hairs. Pubescence on antennal scapes and tibiae appressed to decumbent. Coloration uniformly brown.

Type Material
Hita Garcia et al. (2010) - Holotype worker, SWAZILAND, 2-3 miles S of Mbabane, 2.-4.II.1962, leg. R.L. Ghent [examined]. Paratypes, 3 workers with same data as holotype (MCZ, ) [examined].

Additional References

 * Hita Garcia, F.; Fischer, G.; Peters, M. K. 2010. Taxonomy of the Tetramorium weitzeckeri species group (Hymenoptera: Formicidae) in the Afrotropical zoogeographical region. Zootaxa 2704:1-90.