Key to Europe and Asia Minor Lasius alienus group species

This worker key is based on: [[Media:Seifert, B., Galkowski, C. 2016. The Westpalaearctic Lasius paralienus complex contains three species.pdf|Seifert, B., Galkowski, C. 2016. The Westpalaearctic Lasius paralienus complex (Hymenoptera: Formicidae) contains three species. Zootaxa 4132: 44-58 (DOI:10.11646/zootaxa.4132.1.4).]]

The Lasius alienus group within the European species of the subgenus Lasius s.str. is characterized by no or very few setae on dorsal plane of the scape (differing from the Lasius niger and Lasius emarginatus species groups) and by the masticatory margin of mandibles showing ≥ 8 teeth (differing from the Lasius brunneus group). The data in the key refer to nest sample means.

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Lasius

1

 * Sparsely haired: nSt 0–1.3, nOcc < 8.0, nGu 0–2.5, nHT 0–1. Propodeal dome in medium-sized specimens more conic. Scape shorter: SL/CL 0.921 ±0.019. Body concolorous dark brown . . . . . Lasius alienus


 * Less sparsely haired: nSt 1.8–8.0, nOcc 5.2–18.0, nGu 0.9–4.8, nHT 0–8. Propodeal dome in medium-sized specimens more hemispheric . . . . . 2

2
return to couplet #1
 * Pubescence on head and mesosoma more dilute, nest means of sqPDCL > 3.82. Terminal (6th) segment of maxillary palps shorter: MP6 < 0.140 mm. With CW and MP6 given in mm and PDCL in μm, discriminant 6.164 CW +1.758 sqPDCL –62.482 MP6 –3.718 > 0 [error in 145 samples 0%] . . . . . 3


 * Pubescence on head and mesosoma rather dense: nest means of sqPDCL < 3.82. Terminal (6th) segment of maxillary palps lon-ger: MP6 > 0.140 mm. With CW and MP6 given in mm and PDCL in μm, discriminant 6.164 CW +1.758 sqPDCL –62.482 MP6 –3.718 < 0 [error in 145 samples 0%] . . . . . 4

3
return to couplet #2
 * With all measurements given in mm, discriminant 24.577 CW –125.645 EYE –7.836 SL +0.477 nGen +31.866 GuHL +7.476 > 0 [error in 12 samples 0%]. Iberia, sympatric with psammophilus in S France . . . . . Lasius piliferus


 * With all measurements given in mm, discriminant 24.577 CW –125.645 EYE –7.836 SL +0.477 nGen +31.866 GuHL +7.476 < 0 [error in 58 samples 0%]. Asia Minor and Europe except Iberia . . . . . Lasius psammophilus

4
return to couplet #2
 * Corsica only. Terminal (6th) segment of maxillary palps very long, genae with more numerous setae: MP6/CS >0.200, nGen >2.8 . . . . . Lasius casevitzi


 * European Mainland. Terminal (6th) segment of maxillary palps shorter, genae with less numerous setae: MP6/CS <0.200, nGen <2.8 . . . . . 5

5
return to couplet #4
 * Terminal (6th) segment of maxillary palps longer and longest hair on pronotum shorter. With the metric data of PnHL and MP6 given in mm, discriminant 77.625 PnHL – 107.575 MP6 + 5.916 <0 [error 0% in 49 nest samples]. Europe west to S France and north to S Sweden . . . . . Lasius paralienus


 * Terminal segment of maxillary palps shorter and longest hair on pronotum longer. With the metric data of PnHL and MP6 given in mm, discriminant 77.625 PnHL – 107.575 MP6 + 5.916 >0 [error 0% in 20 nest samples]. Asia Minor, Balkans northwest to east Austria and south Slovakia . . . . . Lasius bombycina