Tetraponera grandidieri

Colonies usually occupy dead twigs or branches on the ground, less commonly in the lower canopy. During field work in Madagascar I collected thirteen nest series of this species, of which nine were in dead wood and four were located in cavities of live plants: three in stems of tree saplings (Ixora sp., Leea sp. and an unidentified plant), and one in a cavity in a live root of a tree in the genus Rhus. There were no scale insects (Coccoidea) in any of these live cavity nests, however, and there is no indication that T. grandidieri is closely associated with any particular plant species. It seems clear that it and other members of the T. grandidieri group occupy moister nest sites than most Tetraponera species. The nests of T. grandidieri apparently contain no more than one dealate queen, and colony sizes are small (5-40 workers). Alate queens and males have been collected from February to May. Workers commonly forage on low vegetation, and they appear to be mimicked by members of the Camponotus putatus complex whose workers forage in similar microhabitats. T. grandidieri is generally absent from disturbed rainforest edge and other high light environments. (Ward 2009)

Identification
Ward (2009) - A member of the Tetraponera grandidieri group. This species is typically bicolored with a black or dark brown head and the remainder of the body a contrasting orange-brown. This allows it to be distinguished from the other two species, Tetraponera inermis and Tetraponera merita, with which it is widely sympatric-both of these usually have the head more or less concolorous with the mesosoma. Some northern populations of T. grandidieri have workers that are unicolorous orange-brown, however, and these superficially resemble the other two species. They can be recognized because they lack a tooth on the basal margin of the mandible (present in T. merita) and the metanotal spiracle protrudes from the rnesosoma dorsum in profile (not protruding in T. inermis). The degree of prominence of the metanotal spiracle varies, however, so it is also useful to examine head shape, which is more elongate in T. grandidieri (worker CI 0.77-0.88 versus 0.88-0.97 in T. inermis; see also additional discussion under T. inermis). T. grandidieri also overlaps in distribution with Tetraponera hespera in northern Madagascar. Where these two species co-occur T. grandidieri has a bicolored body, while T. hespera has a unicolored body and contrasting dark bands on the femora.

At Betampona (17°53'S 49°12'E) Brian Fisher collected three nest series of T. grandidieri: one (BLF13292) with unicolored workers, a second (BLF13298) with bicolored workers, and a third (BLF13349) with both unicolored and bicolored workers, in approximately equal proportions. The Betampona workers with light and dark heads show no obvious differences other than color. The occurrence of both forms in the same nest is consistent with the view that they are conspecific. In addition, genetic data (> 10 kb of sequence data from several nuclear genes and one mitochondrial gene) from populations sampled throughout the range of the species show the two color forms to be phylogenetically comingled (Ward unpubl.).

Distribution
Ward (2009) - Tetraponera grandidieri is widespread in eastern Madagascar, with a distribution that spans the length of the island. Populations are restricted to rainforest, at elevations ranging from sea level to 1375 m. As a result of habitat destruction in the lowlands most populations are found at intermediate or higher elevations.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  grandidieri. Sima grandidieri Forel, 1891b: 203, pl. 5, fig. 3 (w.) MADAGASCAR. Forel, 1891b: 229 (q.m.). Combination in Tetraponera: Wheeler, W.M. 1922a: 1014. Senior synonym of hildebrandti: Ward, 2009: 289.
 * hildebrandti. Sima grandidieri var. hildebrandti Forel, 1891b: 204 (w.) MADAGASCAR. Combination in Tetraponera: Wheeler, W.M. 1922a: 1014. Raised to species: Dalla Torre, 1893: 54. Subspecies of grandidieri: Wheeler, W.M. 1922a: 1014. Junior synonym of grandidieri: Ward, 2009: 289.

Worker
Ward (2009) - n = 13. HW 1.01-1.44, HL 1.20-1.65, LHT 1.07-1.56, CI 0.77-0.88, FCI 0.15-0.17, REL 0.28-0.36, REL2 0.34-0.43, 51 0.74-0.81, FI 0.29-0.36, PLI 0.50-0.59, PWI 0.40-0.53.

With characteristics of the T. grandidieri group; basal margin of mandible edentate; anterior clypeal margin broadly convex and crenulate, directed forward, not anteroventrally; head relatively elongate (CI 0.77-0.88); metanotal spiracle more or less visible in lateral view of mesosoma, protruding dorsally in the mesopropodeal impression; dorsal face of propodeum broadly convex in lateral and posterior views; standing pilosity generally sparse; long paired setae (0.2-0.4 mm in length) distributed as follows: 1 pair between the frontal carinae, 1 pair on upper half of head, 1 pair on the pronotum, 0-2 pairs on the petiole; 1-2 pairs on the postpetiole; standing pilosity scattered on successive abdominal segments (gastric segments 1-4); short appressed to subdecumbent hairs absent or inconspicuous on most of body; integument mostly sublucid, with fine coriarious/puncticulate sculpture; body orange-brown, appendages lighter; head usually dark brown to brownish-black, but concolorous with rest of body in some northern populations (see discussion below); legs uniformly light orange-brown.

Type Material
Ward (2009) - Syntypes, 4 workers, Central Madagascar (Hildebrandt) [examined] [Two of three MHNG syntypes imaged on AntWeb: CASENT0101652, CASENT0102029]. One syntype (CASENT0101652) here designated lectotype.

There are nine specimens of T. grandidieri in the Forel collection in MHNG (Geneva) labeled as “Typus” or “Cotypus” but most are not true types, because the label data exclude this possibility. These non-types include three males (from Andrangoloaka), one dealate queen (from Andrangoloaka) and one worker (from “Nosibe, Village de l'Imerina”), all with a red “Typus” label, and an alate queen (Madagascar /Sikora) labeled “Cotypus.” Only three workers in MHNG are apparently part of the actual type series of T. grandidieri (there is also a syntype worker in MCSN). To avoid confusion I have designated one of the MHNG syntype workers as lectotype.

References based on Global Ant Biodiversity Informatics

 * Fisher B. L. 1997. Biogeography and ecology of the ant fauna of Madagascar (Hymenoptera: Formicidae). Journal of Natural History 31: 269-302.
 * Fisher B. L. 1998. Ant diversity patterns along an elevational gradient in the Réserve Spéciale d'Anjanaharibe-Sud and on the western Masoala Peninsula, Madagascar. Fieldiana Zoology (n.s.)90: 39-67.
 * Fisher B. L. 1999. Ant diversity patterns along an elevational gradient in the Réserve Naturelle Intégrale d'Andohahela, Madagascar. Fieldiana Zoology (n.s.)94: 129-147
 * Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.
 * Ward P. S. 2009. The Ant Genus Tetraponera in the Afrotropical region: the T. grandidieri group (Hymenoptera: Formicidae). Journal of Hymenoptera Research: Festschrift Honoring Roy Snelling, 18: 385-304
 * Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. IX. A synonymic list of the ants of the Malagasy region. Bulletin of the American Museum of Natural History 45: 1005-1055