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 tsingy species group Diagnosis Eleven-segmented antennae; anterior clypeal margin medially impressed; frontal carinae moderately developed, ending between posterior eye margin and posterior head margin, behind posterior eye margin weaker developed; anterior face of mesosoma not well-developed and no distinct anterodorsal margin present; margination between lateral and dorsal mesosoma moderate; mesosoma comparatively high (LMI 40–45); propodeal spines / teeth short to very short, and triangular; propodeal lobes triangular, and in profile of approximately same height and more voluminous than propodeal spines; petiolar node rectangular nodiform, in profile moderately higher than long, in dorsal view longer than wide, anterior and posterior faces approximately parallel, anterodorsal and posterodorsal angles of approximately same height; postpetiole approximately rounded; mandibles weakly sculptured to unsculptured; sculpture on head, mesosoma, and waist segments almost completely reduced; gaster unsculptured, smooth, and shiny; pilosity on dorsal surfaces of head, mesosoma, and waist segments consisting of abundant, comparatively short, fine, standing hairs; first gastral tergite either without any standing hairs at all, only with moderately long, appressed pubescence, or with comparatively short, fine erect pilosity; sting appendage spatulate. Comments This species groups consists of two newly discovered species, whose distribution seems to be endemic to a comparatively small area in Western Madagascar . Both type localities are located either within or in close proximity to Tsingy de Bemaraha National Park. The unique character combination of the T. tsingy group makes it very difficult to confuse with any other Malagasy species group. The most distinctive of these characters is the highly reduced sculpture on head, mesosoma, and waist segments. Of the 19 species groups in the Malagasy region, only the T. bessonii groups and the majority of species from the T. marginatum group display a similar reduction of surface sculpture, but these three groups are unlikely to be misidentified with each other. All the members of the T. bessonii and T. marginatum groups possess long to very long propodeal spines and weakly developed short propodeal lobes, and in profile the propodeal spines are several times longer than the propodeal lobes. In the species of the T. tsingy group one can observe an almost opposite pattern since the propodeal spines/teeth are short to very short and the propodeal lobes are well developed and of approximately the same height as the propodeal spines/teeth. Key to the species of the T. tsingy group (workers) 1. Propodeum with minute teeth; first gastral tergite with short, fine erect pilosity ( Fig. 156 )...................... T. tyrion - Propodeum with moderately short spines; first gastral tergite with short and strongly appressed pubescence ( Fig. 157 )..................................................................................................... T. tsingy