Lasius schaeferi

According to the geographic data of the type locality, it is possible that L. schaeferi lives under the harshest climatic conditions of all Lasius s. str. species worldwide.

Identification
The most similar species among the Himalayan-Tibetan species is Lasius obscuratus. Lasius schaeferi differs from the latter in particular by much more numerous setae on hind tibia (nHT900 12.7 vs. 2.8) which also occur on the distal half of extensor profile. The best separation from the Himalayan species Lasius lawarai and Lasius wittmeri, which show similar shape and setae data, is given by the shorter frontal pubescence (PLF900 29.6 µm; in L. lawarai and L. wittmeri 36.1 and 38.8 µm respectively) and the presence of very distinct erect to suberect setae on hind tibia, the morphology of which differs clearly from the neighboring appressed pubescence hairs. This clear differentiation between setae and pubescence is lost in L. lawarai and L. wittmeri where we observe unclear thickness differences between elongated semierect pubescence hairs and semierect setae. Coloration: Head and mesosoma yellowish-brown, gaster in three specimens yellow, in one specimen yellowish brown.

Presumed to belong to the Lasius obscuratus species complex.

Distribution based on Regional Taxon Lists
Oriental Region: Tibet. Palaearctic Region: China.

Nomenclature

 *  schaeferi. Lasius (Lasius) schaeferi Seifert, 1992b: 40, fig. 30 (w.q.m.) TIBET.

Description
Seifert (2020) - The most similar species among the Himalayan-Tibetan species is Lasius obscuratus. Lasius schaeferi differs from the latter in particular by much more numerous setae on hind tibia (nHT900 12.7 vs. 2.8) which also occur on the distal half of extensor profile. The best separation from the Himalayan species Lasius lawarai and Lasius wittmeri, which show similar shape and setae data, is given by the shorter frontal pubescence (PLF900 29.6 µm; in L. lawarai and L. wittmeri 36.1 and 38.8 µm respectively) and the presence of very distinct erect to suberect setae on hind tibia, the morphology of which differs clearly from the neighboring appressed pubescence hairs. This clear differentiation between setae and pubescence is lost in L. lawarai and L. wittmeri where we observe unclear thickness differences between elongated semierect pubescence hairs and semierect setae. Coloration: Head and mesosoma yellowish-brown, gaster in three specimens yellow, in one specimen yellowish brown.

See table 9 in Seifert 2020 for additional morphometrics. The abbreviated names of various quantitative data shown above are defined here: Seifert 2020 Lasius characters.

Type Material
Seifert (2020) - Holotype plus 4 paratype workers labelled ”II. Dolan Expedition Westchina/Tibet leg. E. Schäfer, 1934/36“, ”131“; depository: Basel.

The label ”131“ refers to station 131 of Ernst Schäfer‘s expedition route which is situated at approximately 33.60°N, 96.58°E and 3900 m and was reached 4 August 1935.