Tetramorium robertsoni

AntWiki: The Ants --- Online
Tetramorium robertsoni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Tetramorium
Species: T. robertsoni
Binomial name
Tetramorium robertsoni
Hita Garcia, Fischer & Peters, 2010

Tetramorium robertsoni P zfmkhym20096090.jpg

Tetramorium robertsoni D zfmkhym20096090.jpg

Specimen Label

Other than showing a preference for open areas, little is known about the biology of Tetramorium robertsoni.


The following character combination distinguishes Tetramorium robertsoni from other members of the complex: CI 93 - 94; antennal scapes moderate (SI 78 - 81); eyes moderate to large (OI 25 - 28); metanotal groove in profile barely impressed; mandibles unsculptured, smooth and shiny; median area of clypeus unsculptured; all dorsal surfaces with simple long, erect to suberect hairs; colour uniformly brown. T. robertsoni has a median area of the clypeus that is unsculptured and its metanotal groove barely impressed in profile, while Tetramorium edouardi has a clypeus with longitudinal rugulation, strongly developed median ruga and a distinctly impressed metanotal groove. Another morphologically related species is Tetramorium rubrum although its possession of a noticeably longer antennal scape (SI 85 - 93) and head (CI 87 - 91) separate it from T. robertsoni (SI 78 - 83, CI 92 - 95). Also, both species occur far apart from each other since T. rubrum occurs only in West Africa while T. robertsoni is only known from Tanzania. Additionally, T. robertsoni can be easily discriminated from Tetramorium philippwagneri and Tetramorium schoutedeni since the latter two have relatively small eyes (OI 21 - 22) and are distinctly bicoloured, whereas T. robertsoni shows larger eyes (OI 25 -28) and an uniform coloration. Finally, the simple hairs of T. robertsoni distinguish it clearly from the species with bizarre pilosity (Tetramorium pinnipilum, Tetramorium rogatum, Tetramorium zonacaciae), or without any standing hairs on mesosoma, waist segments, and gaster (Tetramorium mkomazi).

A member of the Afrotropical edouardi species complex, which is part of the weitzeckeri species group.

Keys including this Species


Known only from a few localities in Tanzania.

Latitudinal Distribution Pattern

Latitudinal Range: -3.966666667° to -3.966666667°.

Tropical South

Distribution based on Regional Taxon Lists

Afrotropical Region: United Republic of Tanzania.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.




The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • robertsoni. Tetramorium robertsoni Hita Garcia, Fischer & Peters, 2010b: 33, figs. 23A, 37-39 (w.) TANZANIA.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



HL 0.800 - 0.906 (0.849); HW 0.744 - 0.844 (0.794 ); SL 0.589 - 0.700 (0.647); EL 0.189 - 0.222 (0.206); PW 0.589 - 0.689 (0.637); WL 0.967 - 1.222 (1.098); PSL 0.244 - 0.339 (0.301); PTL 0.211 - 0.289 (0.249); PTH 0.300 - 0.378 (0.334); PTW 0.267 - 0.367 (0.311); PPL 0.256 - 0.300 (0.276); PPH 0.311 - 0.389 (0.343); PPW 0.367 - 0.444 (0.395); CI 92 - 95 (94); SI 78 - 83 (81); OI 25 - 28 (26); PSLI 31 - 39 (35); PeNI 44 - 55 (49); LPeI 68 - 80 (74); DPeI 119 - 132 (125); PpNI 60 - 67 (62); LPpI 74 - 86 (81); DPpI 132 - 156 (143); PPI 121 - 138 (128) (8 measured).

Head slightly longer than wide (CI 92 - 95). Anterior clypeal margin with small but distinct median impression. Frontal carinae strongly developed, less strongly developed behind eye level, ending shortly before posterior margin of head. Antennal scrobe shallow, narrow, and without defined posterior and ventral margins, ending before posterior margin of head. Antennal scape of medium size, not reaching posterior margin of head (SI 78 - 83). Eyes moderate to relatively large (OI 25 - 28), with 10 to 12 ommatidia in longest row. In lateral view metanotal groove not or barely impressed. Propodeal spines long and spinose (PSLI 31 - 39). Propodeal lobes small, triangular and acute. Petiolar node high nodiform, in dorsal view slightly wider than long (DPeI 119 - 132), in profile around 1.2 to 1.4 times higher than long (LPeI 68 - 80). Postpetiole in dorsal view between 1.2 to 1.6 times wider than long (DPpI 132 - 156); in lateral view rounded, around 1.1 to 1.3 times higher than long (LPpI 74 - 86). Mandibles unsculptured, smooth and shiny. Clypeus few rugae laterally, median area unsculptured and shiny. Head mostly longitudinally rugose with 7 to 8 widely spaced longitudinal rugae between frontal carinae, running unbroken to posterior margin of head. Mesosoma with mostly longitudinal rugulation, propodeal declivity unsculptured. Ground sculpturation on head and mesosoma smooth and shiny. Petiole and postpetiole mostly longitudinally rugose; gaster completely unsculptured, smooth and shiny. All dorsal surfaces of head, mesosoma, petiole, postpetiole, and gaster with many long, simple, suberect to erect hairs. Fine pubescence on antennal scapes and tibiae decumbent to suberect. Coloration brown, appendages of lighter colour.

Holotype Specimen Labels

Type Material

Holotype worker, TANZANIA, Mkomazi Game Reserve, Ibaya, 03° 58' S, 37° 48' E, savanna, unburnt slope, ex pitfall trap, 14.XI.1994, leg. A. Russell-Smith (The Natural History Museum: ZFMK_HYM_2009_6090). Paratypes, 2 workers with same data as holotype (BMNH: ZFMK_HYM_2009_6089, ZFMK_HYM_2009_6091); 5 workers from TANZANIA, Amani, 850m, 9.XI.1957, leg. E.S. Ross & R.E. Leech (California Academy of Sciences: 4 workers CASENT0218274, CASENT0218276, CASENT0218277, CASENT0218278; ZFMK: 1 worker CASENT0218275).


This species is dedicated to Dr. Hamish G. Robertson from South Africa in honour of his work in Afrotropical myrmecology.


  • Hita Garcia, F.; Fischer, G.; Peters, M. K. 2010. Taxonomy of the Tetramorium weitzeckeri species group (Hymenoptera: Formicidae) in the Afrotropical zoogeographical region. Zootaxa 2704:1-90.