Lasius orientalis

Identification
Within the subgenus distinctive by its flattened antennal scape and the very thick, low petiolar scale (in profile), which is gradually widened to the apex when seen in front or from behind.

Distribution
Radchenko (2005) - Southern part of Russian Far East (Amursky and Primorsky Regions, Islands Shikotan and Kunashir), Korean Peninsula, Japan (Hokkaido, northern and central Honshu).

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

Nomenclature

 *  orientalis. Lasius fuliginosus var. orientalis Karavaiev, 1912b: 586 (w.) KOREA. Junior synonym of fuliginosus: Wilson, 1955a: 138; of nipponensis: Espadaler, Akino & Terayama, 2002: 340. Revived from synonymy, raised to species and senior synonym of ouchii, teranishii: Radchenko, 2005a: 87.
 * teranishii. Lasius (Chthonolasius) teranishii Wheeler, W.M. 1928d: 120 (q.) JAPAN. Yamauchi & Hayashida, 1968: 399 (w.m.). Combination in L. (Dendrolasius): Wilson, 1955a: 146. Senior synonym of ouchii: Wilson, 1955a: 146. Junior synonym of orientalis: Radchenko, 2005a: 87. See also: Yamauchi, 1979: 174; Kupyanskaya, 1989: 786.
 * ouchii. Lasius (Chthonolasius) ouchii Teranishi, 1940: 76 (q.) JAPAN. Junior synonym of teranishii: Morisita, 1945: 23; of orientalis: Radchenko: 2005: 87..

Worker
Radchenko (2005) - (neotype in brackets) workers from the nest of the neotype specimen (n = 16) [mean data are in square brackets]: HL1 = 1.06-1.26 (1.22) [1.17], HL2 = 1.12-1.33 (1.32) [1.25], HW1 = 1.04-1.23 (1.19) [1.15], HW2 = 0.70-0.80 (0.77) [0.75], SL = 1.01-1.12 (1.09) [1.06], OL = 0.18-0.27 (0.25) [0.23], AL = 1.18-1.44 (1.34) [1.32]; CI = 0.96-1.00 (0.98) [0.98], CLI = 1.05-1.09 (1.08) [1.07], CWI = 1.49-1.57 (1.55) [1.54], SI1 = 0.88-0.95 (0.90) [0.90], SI2 = 0.89-0.96 (0.92) [0.92], OI = 0.18-0.22 (0.21) [0.20].

Petiolar scale (seen in proflle) thick, low, not narrowing to the top; when seen in front or from behind, it gradually widens to the top; scape distinctly flattened, ratio of min/max diameters of the scape ≤ 0.5; head with convex sides, gradually and slightly narrowing anteriorly, with emarginate occipital margin; scape and legs with numerous short subdecumbent hairs; promesonotal dorsum and occipital margin with a few quite short standing hairs.

Queen
Radchenko (2005) - Petiolar scale (seen in profile) thick, low, not narrowing to the top; when seen in front or from behind it gradually widens to the top; scape and legs, including the first tarsal joint, remarkably flattened, ratio of min/max diameters of scape and hind tibiae ≤ 0.4; head with emarginate occipital margin, but not cordiform and at most slightly wider than long; legs and scape with very dense decumbent pubescence; head, alitrunk and gaster with very dense decumbent pubescence; alitrunk dorsum with sparse, short erect hairs.

Type Material
Radchenko (2005) -Neotype worker (designated here, see below), “Buhta Gaidamak, No. 3196, 2l.V.1900, leg. P. Shmidt”, “Lasius fuliginosus var. orientalis Karaw. Typus” (both labels hand written by Karawajew).