The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region — taxonomy of the T. bessonii, T. bonibony, T. dysalum, T. marginatum, T. tsingy, and T. weitzeckeri species groups Author Garcia, Francisco Hita Author Fisher, Brian L. text Zootaxa 2012 2012-07-04 3365 1 123 journal article 20762 10.11646/zootaxa.3365.1.1 1db9bc74-46dd-4263-9784-88a59bd05d59 1175­5334 6038900 Tetramorium weitzeckeri species group Diagnosis Eleven-segmented antennae; anterior clypeal margin medially impressed; frontal carinae well-developed, almost reaching posterior head margin; anterior face of mesosoma not well-developed and no distinct anterodorsal margin present; no distinct margination between lateral and dorsal mesosoma, sides of mesosoma smoothly rounding onto the dorsum; mesosoma comparatively high (LMI 45–48); propodeal spines long and spinose; propodeal lobes triangular and short; petiolar and postpetiolar nodes strongly squamiform and anteroposteriorly compressed, in profile much higher than long, in dorsal view much wider than long and transverse, anterior and posterior faces parallel, antero- and posterodorsal margins at about same height; mandibles longitudinally rugose; cephalic sculpture well-developed, mostly reticulate-rugose with reticulate-punctate ground sculpture; mesosoma very weakly sculptured to unsculptured; waist segments and gaster unsculptured, smooth, and shiny; dorsal surfaces of head, mesosoma, and waist segments with erect hairs, much scarcer on mesosoma and waist segments; first gastral tergite without standing hairs, with short, appressed pubescence only; sting appendage spatulate. Comments The T. weitzeckeri group is of primarily Afrotropical distribution with 27 known species ( Hita Garcia et al., 2010 ). Only one member of the group, T. humbloti , is present in the Malagasy region, and seems very likely to have been transferred from the Afrotropical region. This species has a wide distribution range in East and South Africa , and has established itself on many islands of the South West Indian Ocean ( Bolton, 1979 ; Hita Garcia & Fisher, 2011 ). In the Malagasy region, T. humbloti is not likely to be confused with any other Tetramorium due to its strongly squamiform petiole and postpetiole. No other genus member in the region possesses this squamiform condition of both waist segments, whereas it is present in several African species of the T. weitzeckeri group. This also supports the African origin of T. humbloti .