Lasius capitatus

Identification
Radchenko (2005) - Workers: petiolar scale (seen in profile) relatively thin, though not flattened at the top, approximately inversely V-shaped; when seen in front or from behind, it is slightly narrowing, not tapering to the dorsal crest; head with convex sides, gradually and slightly narrowing anteriorly, with rather shallowly emarginate occipital margin; scape, mid and hind tibiae not flattened, elliptical in cross-section; ratio of min/max diameters of the scape > 0.7; scape and legs with decumbent pilosity only; promesonotal dorsum and occipital margin with short and sparse standing hairs; third joint of maxillary palps is the longest, each following joint is somewhat longer than the next one; The combination of these features distinctly separates this species both from Lasius nipponensis and Lasius fuji.

Lasius capitatus seems the most similar to Lasius morisitai by the shape of the petiolar scale and by the short standing hairs on alitrunk and head, but workers of the latter species have a somewhat transversal head, which is wider than long (CI ≤ 1.00 in type specimens of L. capitatus and ≥ 1.04 in L. morisitai); these species also differ by the presence of short but distinct subdecumbent hairs on the scape of L. capitatus, while scape of L. morisitai has dense decumbent pubescence only.

Distribution based on Regional Taxon Lists
Palaearctic Region: Japan, Republic of Korea, Russian Federation.

Castes
Known only from the worker caste.

Nomenclature

 *  capitatus. Acanthomyops fuliginosus subsp. capitatus Kuznetsov-Ugamsky, 1927e: 187 (w.) RUSSIA. [Also described as new by Kuznetsov-Ugamsky, 1928b: 18.] Combination in Lasius: Wilson, 1955a: 138. Junior synonym of fuliginosus: Wilson, 1955a: 138. Revived from synonymy and raised to species: Kupyanskaya, 1989: 785. See also: Radchenko, 2005a: 85.

Worker
Radchenko (2005) - Type specimens (data of the lectotype are in brackets): HL1 = 1.25-1.29 (1.29), HL2 = 1.32-1.36 (1.36), HW1 = 1.22-1.27 (1.27), HW2 = 0.78-0.85 (0.85), SL = 1.11-1.12 (1.12), OL = 0.24-0.27 (0.27), AL = 1.34-1.44 (1.44); CI = 0.97-1.00 (0.99), CLI = 1.05-1.07 (1.05), CWI = 1.49-1.59 (1.49), SI1 = 0.87-0.89 (0.87), SI2 = 0.89-0.92 (0.88), OI = 0.19-0.21 (0.21).

Type Material
Radchenko (2005) – Lectotype worker, “Okeanskaya nr. Vladivostok, Siberia, VIII-1926, N. Kusnetzov” (probably hand written by Wilson); “Lasius Juliginosus capitatus Kusnetzov LECTOTYPE” (hand written by Wilson); “M.C.Z. Type 30143” (MCZ, designated by Wilson, 1955); paralectotype worker, “Okeanskaya nr. Vladivostok, Siberia, VIII-1926, N. Kusnetzov” (hand written by Wilson); “Turkestan N. Kusnetzov” (Sic!) (printed original label from Kusnetzov's collection); “Lectotype nest series” (hand written by Wilson); “Cotype” (red printed label); “Lasius Juliginosus capitatus Kuzn.-Ugams. det. E. 0. Wilson” (hand written by Wilson); “M.C.Z. Type 30143”; paralectotype worker, “Acanthomyops fuliginosus orientalis (= capitatus m.) Far East Station Okeanskaya near Vladivostok”' (probably hand written by Kusnetzov); “Turkestan N. Kusnetzov” (Sic!) (original printed label from Kusnetzov's collection); “Lectotype nest series” (hand written by Wilson); “Cotype” (red printed label); “M.C.Z. Type 30143” (MCZ). Non-type material: 5 workers from the Russian Far East (IZK, BPI).

Labels of paralectotype specimens are misleading for the presence of the labels “Turkestan N. Kusnetzov” together with the locality “Far East Station Okeanskaya near Vladivostok”. Probably it is simply a labelling error in Kusnetzov's collection.