Tetramorium merina Hita Garcia & Fisher

Head longer than wide (CI 92–95); posterior head margin weakly concave. Anterior clypeal margin with distinct median impression. Frontal carinae usually weakly developed, only slightly raised, often not better developed than cephalic rugulae, and usually fading out halfway between posterior eye margin and posterior head margin. Antennal scrobes present but weak, shallow and without clear and distinct posterior and ventral margins. Antennal scapes short, not reaching posterior head margin (SI 72–75). Eyes relatively large (OI 26–28). Mesosomal outline in profile flat to weakly convex, comparatively low and elongate (LMI 36–38), weakly marginate from lateral to dorsal mesosoma; promesonotal suture absent; metanotal groove very weakly developed to absent. Propodeal spines reduced to very short, triangular, and acute or blunt teeth/denticles (PSLI 8–11), propodeal lobes short, triangular, and acute or blunt, always appearing more voluminous than propodeal teeth, spines and lobes not strongly inclined towards each other. Petiolar node in profile nodiform to high nodiform with well-rounded antero- and posterodorsal margins, around 1.6 to 1.8 times higher than long (LPeI 57–64), anterior and posterior faces approximately parallel, anterodorsal and posterodorsal margins situated at about same height, petiolar dorsum weakly to moderately convex; petiolar node in dorsal view around 1.2 times wider than long (DPeI 117–124), in dorsal view pronotum between 2.3 to 2.7 times wider than petiolar node (PeNI 36–43). Postpetiole in profile globular, approximately 1.3 to 1.4 times higher than long (LPpI 71–80); in dorsal view around 1.3 to 1.4 times wider than long (DPpI 128–136), pronotum between 1.8 to 2.0 times wider than postpetiole (PpNI 50–56). Postpetiole in profile appearing slightly lower or of same height but thicker than petiolar node, postpetiole in dorsal view around 1.3 to 1.4 times wider than petiolar node (PPI 125–142). Mandibles unsculptured, smooth, and shiny; clypeus weakly longitudinally rugulose with two to five lateral rugulae, median area usually completely unsculptured or only weakly sculptured, median ruga usually absent, at most traces present, lateral rugulae often interrupted or irregularly shaped, but at least one lateral rugula well developed on each side; cephalic dorsum between frontal carinae irregularly longitudinally rugulose with eight to ten rugulae; rugulae running from posterior clypeal margin to posterior head margin, often meandering, broken or with cross-meshes; scrobal area mostly unsculptured and laterally merging with surrounding reticulate-rugose sculpture present on lateral head; ground sculpture on head weakly to moderately punctate. Dorsum of mesosoma reticulate-rugose, especially anteriorly, to irregularly longitudinally rugose, lateral mesosoma mostly irregularly longitudinally rugose; ground sculpture on mesosoma weak to absent. Forecoxae mainly unsculptured, smooth, and shining. Waist segments and gaster unsculptured, smooth, and shining. Dorsum of head with numerous pairs of long, fine, standing hairs; dorsum of mesosoma with at least eleven or twelve pairs of long, standing hairs ranging from anterior pronotum to posterior mesonotum, propodeum without long, standing pilosity; petiole usually with two pairs and postpetiole with three to four pairs; first gastral tergite with short, scarce, appressed pubescence in combination with abundant, long, standing hairs. Anterior edges of antennal scapes and dorsal (outer) surfaces of hind tibiae with decumbent to suberect hairs. Body uniformly light brown to dark brown, gaster often of darker brown, appendages usually lighter.

Tetramorium merina is only known from the Central Highlands of Madagascar (Fig. 65). Its distribution ranges from the two southern-most localities Atsirakambiaty and Ankazomivady through Manjakatompo north to Andranomay, Ambohitantely and Sohisika. All localities are montane rainforests situated at elevations of 1410 to 1700 m, where Tetramorium merina appears to live in leaf litter.