Tetramorium zonacaciae

Tetramorium zonacaciae seems to be widely distributed in East Africa but is also known from one collection event from Cameroon. Nonetheless, it appears to be relatively rare considering that only few specimens are known from each locality.

Identification
The unique bizarre pilosity of Tetramorium zonacaciae isolates it clearly from all other species in the group. It differs conspicuously from all other species of the complex in having thick, blunt, and dorso-ventrally flattened hairs that are usually appressed to decumbent. Not considering this key feature it can be set morphologically relatively near Tetramorium edouardi.

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

Key to weitzeckeri-group species.

Distribution
Known from Cameroun, Kenya, Rwanda, Sudan, Tanzania, and Uganda.

Distribution based on Regional Taxon Lists
Afrotropical Region: Kenya, Sudan.

Nomenclature

 *  zonacaciae. Xiphomyrmex zonacaciae Weber, 1943c: 376, pl. 16, fig. 34 (w.) SUDAN. Combination in Tetramorium: Bolton, 1980: 234. See also: Hita Garcia, Fischer & Peters, 2010b: 41.

Worker
Hita Garcia et al. (2010) - HL 0.789 - 0.878 (0.835); HW 0.767 - 0.867 (0.822); SL 0.611 - 0.667 (0.641); EL 0.167 - 0.200 (0.186); PW 0.528 - 0.622 (0.584); WL 0.889 - 1.122 (1.007); PSL 0.222 - 0.267 (0.245); PTL 0.194 - 0.244 (0.216); PTH 0.317 - 0.400 (0.361); PTW 0.228 - 0.289 (0.260); PPL 0.222 - 0.289 (0.251); PPH 0.300 - 0.378 (0.333); PPW 0.289 - 0.378 (0.334); CI 96 - 100 (98); SI 75 - 81 (78); OI 22 - 25 (23); PSLI 27 - 32 (29); PeNI 37 - 47 (45); LPeI 53 - 67 (60); DPeI 114 - 128 (121); PpNI 54 - 61 (57); LPpI 69 - 83 (75); DPpI 120 - 142 (133); PPI 118 - 141 (129) (15 measured).

Head slightly longer than wide to as long as wide (CI 96 - 100). Anterior clypeal margin with distinct median impression. Frontal carinae well developed, less strongly behind eye level, not reaching posterior margin of head. Antennal scrobe shallow, narrow, and without sharply defined posterior and ventral margins, ending before posterior margin of head. Antennal scape moderate, not reaching posterior margin of head (SI 75 - 81). Eyes of medium size (OI 22 - 25), with 8 to 11 ommatidia in longest row. In profile metanotal groove impressed. Propodeal spines long and spinose (PSLI 27 - 32). Propodeal lobes small, triangular and acute. Petiolar node high nodiform, in dorsal view only slightly wider than long (DPeI 114 - 128), in profile around 1.5 to 1.8 times higher than long (LPeI 49 - 67). Postpetiole in dorsal view between 1.2 to 1.5 times wider than long (DPpI 120 - 142); in lateral view rounded, around 1.2 to 1.4 times higher than long (LPpI 69 - 83). Mandibles longitudinally rugose. Clypeus usually irregularly rugose, sometimes longitudinally, median ruga rarely unbroken and strong. Head mostly longitudinally rugose with 9 to 12 widely spaced longitudinal rugae between frontal carinae, most running unbroken to posterior margin of head. Mesosoma generally with longitudinal rugulation, often irregularly, leaving unsculptured areas, especially on pronotal dorsum. Spaces between rugae and propodeal declivity smooth and shiny. Petiole and postpetiole generally smooth and shiny, sometimes weakly rugose; gaster completely unsculptured, smooth and shiny. All dorsal surfaces with abundant hairs, generally appressed to decumbent except for several pairs on cephalic dorsum and gastral apex; hairs on cephalic and mesosomal dorsum directed towards the midline; hairs on mesosoma and especially on first gastral tergite thick, blunt, and dorso-ventrally flattened. Pubescence on antennal scapes and tibiae appressed. Colour medium to dark brown.

Etymology
Hita Garcia et al. (2010) - Syntype workers, SUDAN, Imatong Mts, 7100 ft (2160m), 25.VII.1939, no. 1315, leg. N.A. Weber [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.