Formica glabridorsis Santschi, 1925

Seifert, B. & Schultz, R., 2009, A taxonomic revision of the Formica rufibarbis Fabricius, 1793 group (Hymenoptera: Formicidae)., Myrmecologische Nachrichten 12, pp. 255-272 : 269-271

Formica glabridorsis Santschi, 1925

Formica rufibarbis var. glabridorsis Santschi, 1925 ; China: Beijing .

Type material examined: One syntype worker labelled " Type ", " Pechino S. Folchini 1905", " B. Finzi Coll purch. 1950", " Formia (Servif.) rufibarbis Nyl. glabribarbis Sah Santschi det. 1951", " M. C. Z. CoType 28817"; a second syntype worker without scapes labelled " Pechino S. Fol-chini 1905", " B. Finzi Coll purch.1950", " M. C. Z. CoType 28817", " Jan. - Jun. 2001 MCZ Image Database "; both syn-types MCZ Cambridge.

Material examined: 6 samples with 21 workers from China were subject to a numeric analysis of 18 characters (Fig. 21). For details, see Appendix, as digital supplementary material to this article, at the journal's web pages.

6 samples with 21 workers from China were subject to a numeric analysis of 18 characters. China: Peking (type), 1905 [39.93° N, 116.39° E, coordinates estimated] ; Peking , Summer Palace , 22.VIII.2004 [39.998° N, 116.273° E] ; Shaanxi, Lintong , 25.VIII.1995 [34.333° N, 109.267° E] ; Shaanxi, Wei He River , 22.VIII.1995 [34.400° N, 108.917° E] ; Shaanxi, Zhouzhi , 24.VIII.1995 [34.150° N, 108.283° E] ; Yunnan , Mekong , 05.VI.2006 [27.048° N, 99.157° E] .

Description of worker (Tab. 1, Fig. 11): large Servi-formica species (CS 1.425 mm), head very much elongated (CL / CW1.4 1.164), has the longest scape of the F. rufibarbis group (SL / CS1.4 1.184), distance between ocelli rather low (OceD / CS1.4 0.152), eye relatively large (EYE / CS1.4 0.301). Petiole relatively narrow (PEW / CS1.4 0.430). Clypeus with sharp median keel and fine longitudinal mi-crocarinulae. Frontal triangle finely transversely rippled and with 55 - 75 short pubescence hairs. Eyes with micro-setae of 6 - 9 μ m maximum length. Pronotum, mesonotum, petiole, flexor profile of hind tibia, posterior margin of head, propodeum and dorsolateral metapleuron normally without setae. Ventral coxae and gaster tergites with long setae. Dorsal mesonotum in lateral aspect flatly convex. Meta-notal depression moderately deep. Propodeal dome relatively flat. Dorsal crest of petiole in frontal view convex, sometimes (especially in larger specimens) trapezoidal. Petiole scale in lateral aspect slender, with convex anterior and more straight posterior profile. Gaster with transverse microripples of small [test] distance (RipD 4.2 μ m) and covered by very dense silvery pubescence (sqPDG 2.9). Pubescence on head, mesosoma and petiole dense, producing a rather matt surface appearance. Posterior vertex, often dorsal pro-mesonotum, coxae and all appendages brown, gaster always dark brown. Other body parts reddish brown.

Comments on taxonomy: The character combination of F. glabridorsis is unmistakable at least within the East Asian ant fauna. A full separation from the next similar sympatric species F. tianshanica sp. n. is given alone by the non-overlapping SL / CS1.4 and RipD1.4 data (Tab. 1). The most similar Palaearctic species is the disjunct F. persica sp. n. which is separated by 4200 kilometres. A two-class DA considering the characters CS, CL / CW1.4, SL / CS1.4, OceD / CS1.4, EYE / CS1.4, PEW / CS1.4, RipD1.4, and sqPDG1.4 separated each of the 26 nest samples of these two species with p = 1.000 and the error prediction by a LOOCV-DA was 0%. In addition, we ran a PCA (as an unsupervised method) using the same character set and found the first factor (explaining 28.7% of total variance) to offer a very strong separation of both species: F. persica sp. n. factor 1: -0.503 ± 0.323 [0.02, 1.05] n = 20 F. glabridorsis factor 1: -1.675 ± 0.475 [-2.26, -0.97] n = 6 Distribution and biology: The known distribution is coincident with the southwest, central and northeast Chinese floristic provinces of Meusel & Jäger (1992) and ranges from 27° to 40° N, 99° to 116° E and from 50 metres (in the north) to 1700 metres (in the south). Available habitat information: found in a city park in Beijing and on river banks of Wei Hei and Mekong River.