Lasius capitatus

There is a record of a L. capitatus queen being found in a nest of Lasius productus (Sonobe, 1984), suggesting that this species is a temporary social parasite of L. productus. The nuptial flights take place in Gifu Prefecture, Japan, during September (Yamauchi et al., 1986) (Japanese Ant Image Database).

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.

References based on Global Ant Biodiversity Informatics

 * Choi B.M., K. Ogata, and M. Terayama. 1993. Comparative studies of ant faunas of Korea and Japan. 1. Faunal comparison  among islands of Southern Korean and northern Kyushu, Japan. Bull. Biogeogr. Soc. Japan 48(1): 37-49.
 * Choi B.M., Kim, C.H., Bang, J.R. 1993. Studies on the distribution of ants (Formicidae) in Korea (13). A checklist of ants from each province (Do), with taxonomic notes. Cheongju Sabom Taehakkyo Nonmunjip (Journal of Cheongju National University of Education) 30: 331-380.
 * Maruyama M., F. M. Steiner, C. Stauffer, T. Akino, R. H. Crozier, and B. C. Schlick-Steiner. 2008. A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture. BMC Evolutionary Biology 8:Article 237 (doi:10.1186/1471-2148-8-237).
 * Ran H., and S. Y. Zhou. 2012. Checklist of chinese ants: formicomorph subfamilies (Hymenoptera: Formicidae) II. Journal of Guangxi Normal University: Natural Science Edition 30(4): 81-91.
 * Terayama M. 1992. Structure of ant communities in East Asia. A. Regional differences and species richness. Bulletin of the Bio-geographical Society of Japan 47: 1-31.
 * Terayama M., K. Ogata, and B.M. Choi. 1994. Distribution records of ants in 47 prefectures of Japan. Ari (report of the Myrmecologists Society of Japan) 18: 5-17.
 * Terayama. M. and Y. Watanabe. 1994. Ant fauna of the Zhongyang Mountains in Taiwan. Abstracts of papers presented at 33th Annual Meeting of the Myrmecological Society of Japan held on September 1st and 2nd, 1990, at the Faculty of Arts and Sciences, University of Tokyo. ARI Reports of the Myrmecologists Society (Japan) 18: 32