4.4.29 Lasius platythorax Seifert 1991

Lasius platythorax Seifert 1991 [type investigation]

Type material: Holotype worker labelled ”Oberlausitz, 1 km N Biesig bei Reichenbach 16.4.1988, leg. Seifert“; 5 paratype workers from the holotype nest on two separate pins labelled ” 1 km N Biesig Kr. Reichenbach, 1988, 16.4.“; SMN Görlitz.

All material examined. A total of 109 nest samples with 222 workers were subject to NUMOBAT investigation. These originated from Bulgaria (2 samples), Croatia (1), Czechia (6), England (4), France (5), Germany (53), Greece (2), Ireland (1), Italy (6), Poland (1), Romania (3), Russia (17), Slovakia (1), Sweden (6), Turkey (1). For details see supplementary information S1.

Geographic range. Eurosiberian, largely temperatesubboreal. From Ireland and Scotland across continental Europe and Asia Minor to Central Siberia (east to 105°E). In the Mediterranean (Apennine, Corsica) usually in the montane zone but at 40.8°N even in lowland floodplain forest. In Norway reaching 64.7°N and in Sweden and Finland 66.3°N. In Central Europe from the planar to montane zone, ascending in Vorarlberg to 1500 m.

Diagnosis (Tab. 6, Figs. 57 –58; key; images in www. AntWeb.org with specimen identifiers CASENT0172747, CASENT0172767, CASENT0179929, CASENT0179887, CASENT0179925, CASENT0913673, CASENT0915593):

Absolute size rather large (CS 970 µm). Head length index low (CL/CW 900 1.051), scape moderately long (SL/ CS 900 0.981), postocular distance rather large (PoOc/CL 900 0.248); eye size medium (EYE/CS 900 0.236); terminal segment of maxillary palp rather short (MP6/CS 900 0.176). Number of mandibular dents medium (MaDe 900 8.18). Pubescence on clypeus very sparse (sqPDCL 900 5.02). All body parts with long and numerous standing setae (PnHL/CS 900 0.162, GuHL/CS 900 0.135, nGu 900 11.6, nSc 900 20.0, nHT 900 20.1)). Coloration: whole body homogenously dark brown; scape, metatarsae and tarsae lighter with a yellowish tinge.

Biology. It is mainly a species of woodland habitats but may occur, in particular in regions with cool summer climate, also in open habitats. For details of its biology see Seifert (2018).

Comments. Being an unmistakable combination of low pubescence density, rather long frontal pubescence, long and profuse pilosity, broad head, rather short maxillary palps and moderately long scape, Lasius platythorax is separable by any variant of NC-clustering from the related species L. niger, L. vostochni sp. nov., L. chinensis sp. nov. and L. japonicus with an error of 0%. For separation from the endemic sister species Lasius cyperus sp. nov., see there.