Tetramorium aisha

A species that favors xeric habitats, the types were found in the flood plain of a dry river bed with Salsola aphylla and Acacia karoo, in deep finely grained soils.

Identification
Mbanyana et al (2018) - Morphologically, T. aisha is similar to Tetramorium solidum in that these are the only species in the group with sparse simple erect hairs that are restricted to the mesosoma and petiole only. They can be separated on the basis of the length of the propodeal spines: in T. aisha, the propodeum is only armed with very short propodeal teeth (PSLI 5–9), which are shorter than their basal width, whereas in T. solidum the propodeum is armed with elongate and acute spines (PSL 0.157–0.197).

Distribution
Namibia and South Africa (Western and Northern Cape).

Distribution based on Regional Taxon Lists
Afrotropical Region: Namibia, South Africa.

Habitat
This species has been collected in Nama Karoo, Montane Fynbos, Renosterveld, Kalahari Xeric Savanna and Namib Desert.

Nomenclature

 *  aisha. Tetramorium aisha Mbanyana, Robertson & Hita Garcia, 2018: 10, figs. 4D, L, 5, 24 (w.) SOUTH AFRICA.

Worker
(N = 13) HL 0.993–1.082(1.037); HW 1.023–1.082 (1.060) SL 0.718–0.787 (0.764); EL 0.236–0.275 (0.262); PH 0.393–0.580 (0.474); PW 0.639–0.738 (0.673); WL 1.013–1.208 (1.102); PSL 0.049–0.089 (0.070); PTH 0.305–0.364 (0.335); PTL 0.246–0.328 (0.277); PTW 0.305–0.364 (0.338); PPH 0.375–0.384 (0.356); PPL 0.256–0.344 (0.284); PPW 0.393–0.482 (0.436); OI 22–26 (25); CI 100–108 (102); SI 68–74 (72); DMI 56–68 (61); LMI 33–53 (43); PSLI 5–9 (7); PeNI 47–52 (50); LPeI 75–93 (83) DPeI 108–132 (122); PpNI 61–70 (65); LPpI 64–100 (80); DPpI 131–180 (154); PPI 126–133 (129). Holotype Mandibles with fine longitudinal striations. Anterior clypeal margin with extensive, semicircular indentation. Frontal carinae extending back from frontal lobes as fine ridges ending approximately at level of anterior eye margin. Propodeum armed with pair of short triangular teeth (PSLI 5–9). Metapleural lobes low and rounded. Peduncle with prominent keel-shaped subpetiolar process. Petiolar node in profile nodiform, with posterior face slightly more steeply angled than anterior face; anterior face also rounding into dorsum but with slightly angled corners as seen in dorsal view. Postpetiolar node low and rounded. Dorsal surfaces of head and mesosoma with finely reticulate ground sculpture overlain by longitudinal striations. Petiolar and postpetiolar nodes with fine reticulate sculpture overlain by irregular transverse striations. First gastral tergite with fine, superficial reticulate pattern. Numerous long hairs on clypeus. Ventral surface of head with prominent psammophore. Erect hairs distributed as follows elsewhere: dorsum of head with four pairs; dorsum of mesosoma with three pairs (two on humeri and one on mesonotum); one pair on petiolar node; and numerous hairs on first gastral sternite. Colour uniformly black. Paratypes and other material examined similar to holotype, except for following differences: three to five pairs of long erect hairs on dorsum of mesosoma, arranged as follows; two to four pairs along anterior margin of pronotum and one pair on the mesonotum.

Type Material
Holotype. South Africa: worker, Western Cape, Abrahamskraal, 32.92560° S, 22.01319° E, 516 m a.s.l., flood plain of dry river bed with Salsola aphylla and Acacia karoo, in deep finely grained soils, 15 Apr. 2008, N. Mbanyana, A. Mayekiso and H.G. Robertson leg. (SAM-HYM-C020292). Paratypes. South Africa: 12 pinned workers, same collection data as for holotype (SAM-HYM-C020288 to SAM-HYM-C020292, SAM-HYM-C020316, SAM-HYM-C020329).

Etymology
Named after Aisha Mayekiso, one of the collectors, who is a Collections Manager (Entomology) in the Natural History Collections Department of the Iziko Museums of South Africa.

References based on Global Ant Biodiversity Informatics

 * Mbanyana N., F. Hita Garcia, H. G. Robertson, and J. J. Le Roux. 2018. A taxonomic revision of seed harvester ants of the Tetramorium solidum group (Hymenoptera: Formicidae) in southern Africa. European Journal of Taxonomy 454: 1-59.