Formica tarimica

A Central Asian species, apparently restricted to the Tarim Basin and adjacent foothills of the Tian Shan Mountains at elevations between 850 and 1550 m. Perhaps due to rarity of competing Formica species it occupies a diversity of habitats including semi-desert, pastures, irrigated crop plantations, gardens, open alluvial sand banks, and poplar or tamarisk stands. As a rule, the habitats are found on water-influenced ground, frequently near the Tarim River. Nests in moderately dry sand, often with characteristic slant gateways leading to the underground. Change of nest sites after inundation once observed. Foraging on poplars, probably tending trophobionts. (Seifert and Schultz 2009)

Identification
Seifert and Schultz (2009) - Seeing this orange species walking on the ground of dry steppe or semidesert habitats, F. tarimica could be mistaken on the first glance for F. orangea but the former is easily distinguished by the much more numerous pronotal setae and longer head. The separation of F. tarimica from the other species with similarly large pronotal setae numbers, Formica rufibarbis and Formica anatolica, is figured and with the use of a discriminant analysis.

Distribution based on Regional Taxon Lists
Palaearctic Region: China.

Nomenclature

 *  tarimica. Formica tarimica Seifert & Schultz, 2009: 266, fig. 7 (w.) CHINA.

Worker
Small Serviformica species (CS 1.242 mm), head elongated (CL / CW1.4 1.158), scape moderately long (SL / CS1.4 1.070), has the smallest eyes and the narrowest petiole within the Formica rufibarbis group (EYE / CS1.4 0.281, PEW / CS1.4 0.395). Clypeus with sharp median keel and fine longitudinal microcarinulae. Frontal triangle finely transversely rippled and with 30 - 50 short pubescence hairs. Eyes with microsetae of 7 - 10 μm maximum length. Total mean of unilateral setae numbers on different body parts predicted for a specimen with CS = 1.4 mm: pronotum 12.8, mesonotum 3.2, propodeum plus dorsolateral metapleuron 0.4, petiole dorsal of the spiracle 1.2, flexor profile of hind tibia 0.8, underside of head 0.0. Dorsal mesonotum in lateral aspect broadly convex. Metanotal depression relatively deep. Propodeal dome in profile rounded or angulate-convex. Dorsal crest of petiole in frontal view convex or bluntly angled. Petiole scale in lateral aspect thicker than in other species of the F. rufibarbis group, except Formica orangea sp.n., with convex anterior and straight to slightly convex posterior profile. Gaster with transverse microripples of the largest average distance found in the F. rufibarbis (RipD 7.9 μm) and covered by dense silvery pubescence (sqPDG 3.2). Pubescence on head, mesosoma and petiole less dense. Whole head, mesosoma, coxae, all appendages, and petiole in typical cases reddish yellow, gaster always brown.

Type Material
Holotype worker plus 4 worker paratypes labelled “CHI:42.1251°N,84.4323°E Yengisar, 1515 m R.Schultz 2004.09.03-086” and “Holotype Formica tarimica Seifert & Schultz” / “Paratype Formica tarimica Seifert & Schultz”, SMN Görlitz; from the same nest series: 3 mounted paratype workers and 48 paratype workers in ethanol, coll. RS.

Etymology
From the distribution in the Tarim Basin.