Tetramorium sericeiventre species group

Hita Garcia and Fisher (2011. The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region – introduction, definition of species groups, and revision of the T. bicarinatum, T. obesum, T. sericeiventre and T. tosii species groups. Zootaxa. 3039: 1-72.) provide the following regardomg tje group:

Diagnosis - 12-segmented antennae; anterior clypeal margin entire and without any median impression; lateral clypeus characteristically modified, in full-face view distinctly raised in front of antennal condyle and projecting forward as a tooth or denticle; frontal carinae weakly developed to absent; anterior face of mesosoma weakly developed, margination between dorsal and lateral mesosoma weak to absent; propodeal spines medium-sized; propodeal lobes elongate-triangular and roughly of same length as propodeal spines; petiolar node rectangular nodiform, longer than high to as long as high and longer than wide to as long as wide; postpetiole roughly rounded; mandibles strongly sculptured; sculpturation of head, mesosoma, and waist segments highly variable, usually reticulate-rugose with reticulate-punctulate ground sculpture providing granular appearance, but in one species all possible reductions of this sculpturation observable; first gastral tergite usually sculptured but to variable extent; all dorsal surfaces with sparse to moderately abundant standing pilosity; sting appendage triangular.

Comments - This group is a primarily Afrotropical group with 13 valid species found in this region, all of which are adapted to arid or semiarid habitats. Bolton (1980) divided the group into two complexes on the basis of pilosity. The T. bequaerti complex contains four species that possess abundant standing hairs on the antennal scapes and meso- and metatibiae. The T. sericeiventre complex holds the remaining 9 species, all of which lack standing hairs on the antennal scapes and meso- and metatibiae. Instead, only short decumbent to appressed pubescence is present. Tetramorium sericeiventre clearly belongs to the T. sericeiventre species complex whereas the new species, T. mahafaly, is more difficult to place. Tetramorium mahafaly is a fairly hairy species and possesses pilosity on the antennal scapes and meso- and metatibiae which is appressed. At present, we place this species within the T. bequaerti complex since it shares the presence of distinct pilosity on the antennal scapes and tibiae with the rest of the species complex, even though the pilosity in T. mahafaly is not suberect or erect.

The T. sericeiventre species group does not seem to be morphologically related to the other species groups with 12-segmented antennae. The absence of a notched anterior clypeal margin separates it from the T. bicarinatum group, while the raised lateral portion of the clypeus is not developed in the T. simillimum or the T. tosii groups. The two species of the T. sericeiventre species group, Tetramorium sericeiventre and Tetramorium mahafaly, are relatively easy to differentiate since they differ strongly from one another in terms of body size, petiolar node shape, and especially pilosity.


 * Tetramorium mahafaly
 * Tetramorium sericeiventre