Lasius nigrescens

This species is only known from the alate gynes of the type series.

Identification
Seifert (2020) - The type series of gynes is the only collection of L. nigrescens. Considering the correlations that usually exist between gyne and worker morphology in Lasius, the worker of this species is expected to have a long scape (SL/CS900 perhaps 1.06), an average head length index (CL/CW900 perhaps 1.07), and numerous setae on underside of head and hind tibiae.

Distribution based on Regional Taxon Lists
Palaearctic Region: Russian Federation.

Nomenclature

 *  nigrescens. Lasius emarginatus var. nigrescens Stitz, 1930: 240 (q.) RUSSIA. Junior synonym of niger: Wilson, 1955a: 60. Revived from synonymy and raised to species: Seifert, 1992b: 38.

Queen
Seifert (2020) - I present here the data of 5 type gynes: CS 1411 ± 17 [1392, 1432]; CL/ CW 0.883 ± 0.010 [0.872, 0.896]; SL/CS 0.870 ± 0.010 [0.856, 0.879]; nGu 32.0 ± 5.6 [27, 40], nOcc 29.1 ± 1.6 [27, 31]; nGen 15.2 ± 4.2 [12.5, 20.0]; GuHL/CS 0.112 ± 0.005 [0.107, 0.16]; PnHL/CS 0.147 ±0.005 [0.143, 0.152]; sqPDCL 4.68 ± 0.17 [4.49, 4.89]; ML/CS 2.168 ± 0.036 [2.130, 2.223]; MH/CS 1.146 ± 0.026 [1.122, 1.189]; MW/ CS 1.329 ± 0.006 [1.322, 1.333].

The abbreviated names of various quantitative data shown above are defined here: Seifert 2020 Lasius characters.

Type Material
Seifert (2020) - Lectotype (des. E.O. Wilson) and 4 paralectotype gynes labelled ”West-Pamir, VII-IX 28, leg. Reinig, Maz, 3800 m, 15.-19. VIII“; depository.