Tetramorium pogonion

An arid habitat species that has been found in desert, savannah woodland, and arid areas adjacent to a river. Specimens have been collected from pitfall traps, a dead zebra, and a flowering tree.

Identification
Mbanyana et al. (2018) - Tetramorium pogonion is the only species in the T. solidum species group with the head broader in front of the eyes than behind.

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

Biology
Hawkes (2020) - A 2019 field study sampled 113 T. pogonion in 22 pitfall traps (from 10 transects of 20 traps 10m apart run for 6 days). Transects were placed in the major habitat types (riverine fringe, alluvial terrace gravels, alluvial fans, aeolian sands, Mispah soils and mountain slopes) of a diamond mine concession in northern Richtersveld National Park (Namakwa district, Northern Cape, South Africa). Tetramorium pogonion was found in five of the six habitats.

Nomenclature

 *  pogonion. Tetramorium pogonion Bolton, 1980: 249, fig. 21 (w.q.m.) NAMIBIA.

Worker
Holotype. TL 3.8, HL 1.02, HW 0.86, CI 84, SL 0.76, SI 88, PW 0.58, AL 0.96. Paratypes (6 measured): TL 3.8-4.1, HL 1.00-1.06, HW 0.86-0.92, CI 84-89, SL 0.74-0.77, SI 82-88, PW 0.58-0.62, AL 0.96-1.04. Maximum diameter of eye 0.26-0.28, about 0.29-0.31 x HW.

Mandibles longitudinally rugose. Anterior clypeal margin with a median impression. Frontal carinae short and feeble, the frontal lobes extended back by a weak ridge, which is no stronger than the remaining cephalic sculpture, to a point just behind the level of the anterior margins of the eyes. Antennal scrobes absent. Eyes quite large, maximum diameter 0-26, about 0-30 x HW. With the head in full-face view the occipital margin very shallowly concave, the occipital corners rounded and the sides of the head diverging slightly to the posterior margins of the eyes. Width of head continuing to increase in front of eyes so that the head is broader in front of the eyes than behind them. Propodeal spines elongate and narrow, acute apically. Metapleural lobes low and broadly rounded. Petiole in profile strongly nodiform; in dorsal view slightly broader than long and shaped like a triangle with bluntly rounded angles, much broader behind than in front. Postpetiole in dorsal view subglobular, broader than long and broader than the petiole. Dorsum of head with separated longitudinal costulae or fine rugulae, the spaces between them with superficial ground-sculpture which is somewhat more conspicuous occipitally. Dorsal alitrunk finely reticulate-punctulate with scattered fine longitudinal rugulae on the promesonotum. Petiole and postpetiole very finely and superficially reticulate-punctulate dorsally, appearing granular. Base of first gastral tergite shagreened. Erect hairs absent from dorsal surfaces of alitrunk, petiole, postpetiole and first gastral tergite; present on clypeus, gastral segments behind the first, first gastral sternite and dorsum of head where two pairs occur. Ventral surface of head with a strongly developed psammophore. Hind tibiae with appressed pubescence. Colour uniform blackish brown.

Paratypes: As holotype.

Mbanyana et al. (2018) - (N = 4) HL 0.924–0.954 (0.944); HW 0.875–0.895 (0.887); SL 0.688–0.767 (0.718); EL 0.266–0.285 (0.275); PH 0.452–0.492 (0.470); PW 0.580–0.610 (0.590); WL 0.964–0.983 (0.971); PSL 0.118–0.148 (0.135); PTH 0.275–0.295 (0.289); PTL 0.275–0.295 (0.288); PTW 0.275–0.295 (0.285); PPH 0.305–0.334 (0.325); PPL 0.256–0.275 (0.270); PPW 0.344–0.374 (0.356); OI 30–32 (31); CI 94–95 (94); SI 79–85 (81); DMI 59–63 (61); LMI 47–51 (48); PSLI 13–15 (14); PeNI 47–49 (48); LPeI 97–102 (100); DPeI 97–104 (99); PpNI 58–63 (60); LPpI 79–90 (83); DPpI 125–146 (132); PPI 120–131 (125).

Type Material
Holotype: South West Africa: 37 miles [60 km] W. of Aus. 500 m. 5.v.1958 (E. S. Ron & R. E. Leech). Paratypes. Six workers, 2 males, 3 females with same data as holotype (CASC; ; ).

Mbanyana et al. (2018) – Holotype. worker, Namibia, 37 miles (60 km) W of Aus, 500 m a.s.l., 5 May 1958, E.S. Ross and R.E. Leech leg. (: CASTYPE13390). Paratypes. 8 pinned specimens (5 workers, 1 male, 2 queens), same collection data as for holotype (CASC: CASENT0270793, CASENT0270794).

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.
 * Marsh A. C. 1986. Checklist, biological notes and distribution of ants in the central Namib Desert. Madoqua 14: 333-344.
 * Mbanyana N. 2013. Taxonomy, phylogeny and biogeography of seed-harvesting ants in the Tetramorium solidum-group (Hymenoptera: Formicidae). Masters of Science in the Department of Botany and Zoology at Stellenbosch University 115 pages.
 * 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.