Lasius paralienus Seifert 1992

Seifert, Bernhard, 2020, A taxonomic revision of the Palaearctic members of the subgenus Lasius s. str. (Hymenoptera, Formicidae), Soil Organisms 92 (1), pp. 15-86 : 58

4.4.17 Lasius paralienus Seifert 1992

Lasius paralienus Seifert 1992 [type investigation]

Type material: Holotype plus 4 paratype workers labelled “ Germania: Kr. Bautzen, 2km S Weissenberg: N 066, 11. 7. 1991, leg Seifert; 15 paratype workers with same collecting data but nest sample numbers ”N 005“, ”N 038“, and ”N 221“; 5 paratype workers labelled ” Germania: Kr. Bautzen, 1 km S Niedergurig, 28. 7. 1991, N 086“; 10 Paratype workers with same collecting data but nest sample numbers ”N 223“ and ”N 240“; depository SMN Görlitz.

All material examined. A total of 74 nest samples with 188 workers were subject to NUMOBAT investigation. These originated from Austria (2 samples), Bosnia-Herzegovina (1), Bulgaria (1), Czechia (1), France (1), Germany (45), Greece (1), Italy (18), Slovakia (1), Sweden (2), and Switzerland (2). For details see supplementary information S1. Further 18 samples from Austria (2), Germany (7), Sweden (8), and Switzerland (1) were assessed by simple eye-inspection.

Geographic range. North meridional and temperate zones of Europe. Postglacial invasion of Central Europe and S Scandinavia most probably from a refuge in the Apennine. In the south ranging from S France (0.7°W) over entire Italy east to Bosnia-Herzegovina and Bulgaria (25°E). The main distribution in Central Europe reaches north to about 52.5°N. North of this line only isolated populations are known in Sweden: Södermanland (59.1°N), Öland (56.7°N) and Gotland (57.4°N). In Germany it ascends to 990 m (at 47.9°N), at the southern slope of the Alps to 1850 m. Sympatric with L. bombycina in the Balkans and with L. casevitzi in N Italy.

Diagnosis ( Tab. 4 , Figs. 33 –34; key; images in www. antWeb.org with specimen identifiers CASENT0906118, FOCOL0751):

Absolute size rather small (CS 861 µm). Scape, head and maxillary palp length indices medium (SL/CS 900 0.986, CL/CW 900 1.067, MP6/CS 900 0.183). Number of mandibular dents rather small (MaDe 900 8.04). Clypeal pubescence dense (sqPDCL 900 3.51). Pronotal setae relatively short (PnHL/CS 900 0.135) but significantly longer than the few gular setae (GuHL/CS 900 0.103, nGu 900 2.3). Dorsum of scape and extensor profile of hind tibia without or with only few semierect setae. It differs from L. bombycina by longer scape and terminal segment of maxillary palp as well as shorter pronotal setae; from L. casevitzi by much shorter terminal segment of maxillary palps, shorter pronotal setae and much fewer setae on genae and hind tibia (nGen 900 0.2 vs. 4.2, nHT 900 1.8 vs. 8.6). Coloration: Scape, tibiae, tarsae and mandibles light yellowish brown, all remaining body parts dark to medium brown.

Biology. See Seifert (2018).

Comments. L. paralienus shows no outstanding characters but its character combination is separable by NC-clustering from the three other species of the L. paralienus complex with an error rate of 0%. The population from the Apennine Penisula has a significantly larger body size and torulo-clypeal distance as well as shorter gular setae than the population from outside this area. It forms a separate cluster in NC-Ward ( Fig. 112 ) but I refrain here from giving it a taxonomic status as the other three EDAs do poorly support it. The status of a sample from Sardinia (exposed as outlier in NC-part.hclust and separately listed in Tab. 4 ) appears problematic.

Figures

Figs. 33 and 34: Lasius paralienus; CASENT0906118, photo E. Ortega.

Figs. 112: NC-clustering of 49 nest samples of Lasius paralienus(light grey bars), 20 nest samples of L. bombycina (black bars) and 15 samples of L. casevitzi (dark grey bars).