Camponotus robustus

Camponotus robustus occurs in the rainforests of eastern Madagascar, from Binara in the north to Ivohibe Forest in the south. The species is both terrestrial and arboreal. Its workers forage individually on the forest floor, on lower vegetation, and in the canopy and nest in rotten logs, rotting tree stumps, or in dead branches above the ground.

Identification
Rakotonirina et al. (2016) - A member of the Camponotus edmondi species group. Larger species (CS: 1.882–3.725; ML: 3.098–4.666) with uniformly black to dark brown body color; in profile anterior margin of petiolar node convex and posterior margin straight; level of propodeal dorsum not abruptly lower than level of promesonotal dorsum; pronotum covered with numerous erect hairs and pubescence.

Camponotus robustus is similar to Camponotus ethicus, but the latter has no erect hairs on the dorsum of the mesosoma and has a propodeal dorsum lower than the promesonotum. The remainder of the edmondi group can be distinguished from this species by their smaller size and yellow to brown legs.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 * . Camponotus robustus Roger, 1863a: 135 (w.) MADAGASCAR.
 * Forel, 1891b: 54 (s.).
 * Combination in C. (Myrmentoma): Forel, 1912i: 92;
 * combination in C. (Orthonotomyrmex): Forel, 1914a: 273;
 * combination in C. (Myrmisolepis): Santschi, 1921f: 310;
 * combination in C. (Myrmepinotus): Emery, 1925b: 127.
 * Status as species: Roger, 1863b: 2; Mayr, 1863: 459; André, 1882a: 148 (in key); Forel, 1886f: 187; Forel, 1891b: 54 (redescription); Dalla Torre, 1893: 250; Emery, 1896d: 377 (in list); Wasmann, 1897: 250; Wheeler, W.M. 1922a: 1049; Emery, 1925b: 127; Bolton, 1995b: 120; Rakotonirina, et al. 2016: 135 (redescription).

Worker
Rakotonirina et al. (2016) - Minor. In full-face view head rectangular and longer than broad (CWb/CL: 0.91–0.98); lateral margins nearly straight and slightly diverging posteriorly; posterior margin broadly convex. Eyes not breaking lateral outline of head, posterior level located at posterior fourth portion of head (PoOc/CL: 0.21–0.27). Anterior clypeal margin broadly triangular. Mandible triangular, apical margin armed with six teeth. More than apical third portion of antennal scape surpassing posterior cephalic margin. Anterodorsal corner of pronotum projecting anteriorly into narrow ridge; anterior margination strong near corner and weak towards the center; pronotal dorsum rounding to lateral portion. In dorsal view, mesonotum broader than long. In lateral view, mesonotal dorsum slightly inclined posteriorly as is the propodeal dorsum, which joins the declivity at a blunt angle; mesopleuron and propodeal surface together distinctly longer than lateral portion of pronotum; propodeal spiracle located on lateral portion of propodeum anterior to posterolateral margin. Maximum width of procoxa larger than width of mesometapleuron. In profile anterior margin of petiolar node convex and posterior margin more or less straight. Constriction between abdominal segments III and IV absent.

Dorsum of head, mesosoma, and gaster finely and densely reticulate rugose. Lateral portion of head finely and densely reticulate punctate. Mandible imbricate superimposed with punctures. Whitish yellow erect hairs numerous on head, mesosoma, and gaster. Petiole with erect hairs from lateral margins to posterodorsal angle. Pubescence abundant. Head, mesosoma, antennal scape, and distal portion of flagellum, femur, tibia, and basitarsus black; trochanter and metatarsi as well as basal portion of flagellum brown.

Major. With characteristics of minor worker, except: head broader than long (CWb/CL: 0.98–1.02); sides slightly convex and strongly converging towards base of mandibles. Eyes located more anteriorly, their posterior level on posterior third of head (PoOc/CL: 0.26–0.3). Antennal scape barely extending beyond posterior cephalic margin. Anteromedian portion of pronotum without margination. Lateral portion of head smooth and shining with scattered small punctures from which short hairs arise. Mandible with longitudinal striation near apical margin apart from fine imbrication and piligerous punctures.

Type Material


Paralectotypes of 5 workers: 2 in the same pin as lectotype; 2 workers with the same data but specimen coded as CASENT0104621 and CASENT0104622.

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. 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.
 * Forel A. 1886. Études myrmécologiques en 1886.. Annales de la Société Entomologique de Belgique. 30: 131-215.
 * Forel A. 1887. Fourmis récoltées à Madagascar par le Dr. Conrad Keller. Mitteilungen der Schweizerischen Entomologischen Gesellschaft 7: 381-389.
 * Forel A. 1897. Ameisen aus Nossi-Bé, Majunga, Juan de Nova (Madagaskar), den Aldabra-Inseln und Sansibar, gesammelt von Herrn Dr. A. Voeltzkow aus Berlin. Mit einem Anhang über die von Herrn Privatdocenten Dr. A. Brauer in Marburg auf den Seychellen und von Herrn Perrot auf Ste. Marie (Madagaskar) gesammelten Ameisen. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft 21: 185-208.
 * 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