Lasius balearicus Talavera & al. 2014

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 : 69

4.4.37 Lasius balearicus Talavera & al. 2014

Lasius balearicus Talavera, Espadaler & Vila 2014

[type investigation]

Type material: 3 paratype workers from the holotype nest labelled ”Col des Prat, Escorca, Mallorca Spain 39°48‘29.86“N 2°51‘4.52“E 1194 m 13.x.2008 code 08R384 R. Vila & G. Talavera leg.“; depository: SMN Görlitz.

All material examined. Only the type sample was available.

Geographic range. Island endemic. Only known from the top summits of the island of Mallorca at elevations between 800 and 1400 m.

Diagnosis ( Tab. 7 , Figs. 71 –72; key):

A species related to L. cinereus and L. grandis . Absolute size small (CS 850 µm; according to Talavera et al. (2014) ranging from 0.69–0.93 mm). Head and scape length indices large (CL/CW 900 1.094, SL/CS 900 1.011); postocular distance and torulo-clypeal distance higher than in Iberian sister species (PoOc/CL 900 0.234, dClAn 900 5.43); eye size rather small (EYE/CS 900 0.236); terminal segment of maxillary palp rather short (MP6/CS 900 0.186). Number of mandibular dents large (MaDe 900 8.60). Pubescence on clypeus more dilute than in sister species (sqPDCL 900 5.00); frontal pubescence very short (PLF 900 23.0). All body parts with very numerous standing setae of medium length, number of genal setae in particular much larger than in Iberian sister species (PnHL/CS 900 0.135, GuHL/CS 900 0.133, nGen 900 14.5, nGu 900 17.8, nSc 900 22.6, nHT 900 20.1). As difference to L. cinereus , the surface within the meshes of the microreticulum on lateral pronotum is perfectly smooth and shining. In contrast, and resembling the situation in L. cinereus , fine punctures (ultrastructures) within these meshes are present on dorsum of pronotum – as result the surface appears completely matt. Meshes of microreticulum on dorsum of head without or with only occasionally these ultrastructures. Coloration: the entire body is yellowish brown, with head and gaster slightly darker and antennae and tarsae slightly paler.

Biology. According to Talavera et al. (2014), it is typically found on limestone ground with a lot of bare rock and sparse and shrubby vegetation, frequently associated with endemic plants Hypericum balearicum and Genista valdes-bermejoi . Nests were under stones. The ants tended aphids. Restriction of the distribution to the top summits of Mallorca induces a risk of extinction by global warming.

Comments. According to mtDNA data it is supposed to have diverged from its sister species L. grandis and L. cinereus about 1.5 Ma b.p. ( Talavera et al. 2014). The identification of L. balearicus should be clear by a combination of small size, very high setae numbers on basically all body parts, the shape characters reported above and the peculiar distribution.

Figures

Figs. 71 and 72: Lasius balearicus; paratype