Tetramorium grandinode

Specimens have been collected using pitfall traps and tuna, sugar, and cookie baits. One sample was taken from a nest deep in the soil of a flood plain.

Identification
Mbanyana et al (2018) - The remarkable lateral extensions of both petiolar and postpetiolar nodes distinguish T. grandinode from all other species in the T. solidum species group. This species has superficial similarities with Tetramorium duncani in that T. duncani also has a broader postpetiole, but to a much lesser extent (DPpI 104–123) compared to T. grandinode (DPpI 184–322). Moreover, T. grandinode has a much broader petiole node when viewed dorsally compared to T. duncani. Additionally, these two species can be separated on the basis of the mesosoma sculpture: in T. grandinode, the dorsal surface has fine longitudinal rugulae and a glossy appearance in between, whereas in T. duncani it has a reticulate ground sculpture overlain by short fine longitudinal striations.

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

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

Habitat
Known from Kalahari Xeric Savanna, Nama Karoo, Succulent Karoo, Namibian Savanna Woodlands and the Namib Desert.

Biology
Hawkes (2020) – Tetramorium grandinode was found in 2 of 200 pitfall traps sampling six habitats in a diamond mine concession in northern Richtersveld National Park (Namakwa district, Northern Cape, South Africa). The two pitfall traps with T. grandinode were in riverine fringe habitat with open, sparse vegetation. It was dominated by two indigenous tree species, Euclea pseudebenus E. Mey. ex A. DC (Black Ebony) and Tamarix usneoides E. Mey. ex Bunge (Wild Tamarisk). The type specimens of Tetramorium nama were also collected from this same habitat.

Nomenclature

 *  grandinode. Tetramorium grandinode Santschi, 1913c: 308 (w.) SOUTH AFRICA. Senior synonym of hopensis: Bolton, 1980: 247.
 * hopensis. Tetramorium grandinode var. hopensis Forel, 1914d: 223 (w.q.) SOUTH AFRICA. Junior synonym of grandinode: Bolton, 1980: 247.

Worker
TL 5.0—5.3, HL 1.24-1.32, HW 1.18-1.25, CI 95-97, SL 0.88-0.92, SI 72-75, PW 0.82-0.90, AL 1.30-1.40 (5 measured).

Mandibles lightly longitudinally rugose, only faint in some specimens. Anterior clypeal margin with a median shallow semicircular impression. Frontal carinae very short, fading out close behind the frontal lobes, scarcely reaching the level of the anterior margins of the eyes. Antennal scrobes absent. Maximum diameter of eye 0:32-0:34, about 0:26-0:27 x HW. Pronotum in dorsal view transversely marginate anteriorly. Dorsal outline of alitrunk unbroken in profile, the metanotal groove not impressed. Propodeal spines elongate and strong, metapleural lobes low and rounded. Petiole in profile with the body of the node high-rectangular but the more lateral portions antero-posteriorly compressed and extended, and the posteroventral portion of the tergum extended and downcurved. A carina is present which curves upwards from the base of this projection to the petiolar spiracle. In dorsal view the petiole node is much broader than long (maximum width c. 0-60—0-64), and is broader behind than in front. Postpetiole in dorsal view enormously expanded laterally by projecting thick alar extensions so that the maximum width (c. 0-76-0-84) is only slightly less than the PW, and is slightly greater than the basal width of the first gastral tergite. In anterior view the extensions of the postpetiole tergum are seen to project well beyond the sternal portion. Dorsum of head very finely and densely longitudinally costulate, the more lateral costulae diverging posteriorly and curving onto the occipital lobes where they curve round and down the sides of the head and straighten out below the eye. Ground-sculpture between the costulae vestigial, the surfaces glossy. Dorsal alitrunk predominantly longitudinally costulate or fine rugulose, but usually with a few transverse components on the anterior pronotum, behind which some costulae are commonly curved or whorled. Dorsal surfaces of petiole and postpetiole transversely costulate or rugulose. Base of first gastral tergite finely and densely superficially punctulate or shagreened. Hairs of any description absent on the dorsal surfaces of the head and body except on the clypeus and gastral segments behind the first. Dorsum of head typically with two pairs of erect hairs behind the level of the clypeus, one pair at about the level of the anterior margins of the eyes and the second on the occipital corners. Scapes and tibiae with appressed pubescence only. Colour very deep reddish brown to blackish brown.

Mbanyana et al (2018) - (N = 26) HL 1.003–1.229 (1.122); HW 0.962–1.229 (1.095); SL 0.757–0.885 (0.816); EL 0.248–0.354 (0.301); PH 0.462–0.679 (0.528); PW 0.669–0.856 (0.743); WL 0.915–1.377 (1.189); PSL 0.197–0.275 (0.240); PTH 0.374–0.521 (0.431); PTL 0.246–0.344 (0.297); PTW 0.384–0.659 (0.523); PPH 0.384–0.570 (0.450); PPL 0.207–0.315 (0.255); PPW 0.482–0.875 (0.652); OI 27–29 (27); CI 95–102 (98); SI 68– 180 (75); DMI 59–79 (63); LMI 39–54 (44); PSLI 19–24 (21); PeNI 56–83 (70); LPeI 58–85 (70); DPeI 130–212 (177); PpNI 68–110 (87); LPpI 45–73 (57); DPpI 184–322 (257); PPI 118–134 (124).

Type Material
Mbanyana et al (2018) - South Africa: syntype of Tetramorium grandinode Santschi, 1913: worker, Western Cape, Cape Colony (: CASENT0915017); syntype of Tetramorium grandinode var. hopensis Forel, 1914, worker, Northern Cape, Orange River, Hope Town (: CASENT0909135).

References based on Global Ant Biodiversity Informatics

 * Arnold G. 1917. A monograph of the Formicidae of South Africa. Part III. Myrmicinae. Annals of the South African Museum. 14: 271-402.
 * Forel A. 1914. Formicides d'Afrique et d'Amérique nouveaux ou peu connus. Bulletin de la Société Vaudoise des Sciences Naturelles 50: 211-288.
 * Koch F., and K. Vohland. 2004. Ants along a southern African transect - a basis for biodiversity change monitoring (Insecta, Hymenoptera, Formicidae). Zoosystematics and Evolution 80(2): 261-273.
 * Marsh A. C. 1985. Forager abundance and dietary relationships in a Namib Desert ant community. S. Afr. J. Zool. 20: 197-203.
 * Marsh A. C. 1986. Ant species richness along a climatic gradient in the Namib Desert. Journal of Arid Environments 11: 235-241.
 * 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.
 * Santschi F. 1913. Glanures de fourmis africaines. Annales de la Société Entomologique de Belgique 57: 302-314.
 * Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004