Lasius nipponensis

Forel (1912) described L. fuliginosus var. nipponensis from workers and queen from Japan (vicinity .of Tokyo). The most important features, separating the workers of this form from those of L. fuliginosus, have been emphasized in the original description: “...lecaille de l'ouvriere est assez tranchante et non obtuse, la tete est plus retrecie devant .. :· [e.g.: ... ·the petiolar scale of the worker is rather sharp (thin) and not blunt, the head is narrower anteriorly ... ] (loc. cit., p. 339).

Identification
An eastern Asian species most readily distinguished by the aberrant pilosity and pubescence of the queen caste.

Radchenko (2005) - Workers: petiolar scale (seen in profile) thin, distinctly narrowing to the top and with flattened dorsal crest, symmetrical; seen in front or from behind, it is the widest at the level of the spiracles, clearly tapering to the top, its dorsal crest narrowly rounded, without notch; head in full face view distinctly narrowing anteriorly and with 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 numerous subdecumbent hairs; promesonotal dorsum and occipital margin with rather long standing hairs; body with sparse, short decumbent pubescence.

Queens: petiolar scale (seen in profile) thin, narrowing to the top; head in full face view distinctly narrowing anteriorly, with almost straight lateral margins in front of the eyes, and with hardly emarginate occipital margin; scape, mid and hind tibiae not flattened, elliptical in cross-section; ratio of min/max diameters of the scape > 0.7; legs and scape with dense decumbent pubescence and numerous subdecumbent hairs; head, alitrunk and gaster with very abundant, long, often curved standing hairs.

Distribution
Radchenko (2005) - Southern part of Russian Far East (Primorsky Region), Korean Peninsula, Japan (Hokkaido, Honshu, Shikoku), Taiwan.

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

Nomenclature

 *  nipponensis. Lasius fuliginosus var. nipponensis Forel, 1912l: 339 (w.q.) JAPAN. Junior synonym of fuliginosus: Wilson, 1955a: 138; Yamauchi, 1979: 171. Revived from synonymy and raised to species: Espadaler, Akino & Terayama, 2002: 340. Senior synonym of crispus Wilson: Radchenko, 2005a: 84.
 * crispus. Lasius (Dendrolasius) crispus Wilson, 1955a: 144 (w.q.m.) JAPAN. [Unresolved junior primary homonym of crispus Théobald, above.] Junior synonym of capitatus: Kupyanskaya, 1989: 785; of nipponensis: Radchenko, 2005a: 84. See also: Yamauchi, 1979: 174.

Worker
Radchenko (2005) - HL1 = 1.09-1.25, HL2 = 1.15-1.30, HW1 = 1.09-1.26, HW2= 0.67-0.76, SL = 1.01-1.18, OL = 0.23-0.25, AL = 1.26-1.51; CI = 1.00-1.01, CLI = 1.04-1.05, CWI = 1.63-1.67, SI1 = 0.92-0.94, SI2 = 0.92-0.94, OI = 0.20-0.21.

Wilson (1955) – description of synonym Lasius crispus: Two workers from Ueda, Honshu, and a small series from central Korea are tentatively and with great reservation placed in this species and used for the following diagnosis.

(1) The standing hairs of the second and third gastric tergites, anterior to the extreme posterior strips, as long as those of the pronotum or longer. In the Ueda series but not in the Korean series, femora with numerous outstanding decumbent to suberect hairs. Cephalic and gastric pilosity denser than in fuliginosus.

(2) Petiolar crest viewed from the side thinner and sharper than in fuliginosus, the anterior and posterior faces less convex (Pl. 2, Fig. 8).

PW of Ueda workers 0.64 and 0.72 mm., of Korean series 0.77-0.87 mm.

Queen
Wilson (1955) – description of synonym Lasius crispus: 1) Body and appendage hairs much finer than in fuliginosus, many curved at the tip or even sinuate. On the appendages, where the pilosity is predominantly decumbent to subdecumbent, the hairs are frequently wicket-shaped in addition, recurving to touch the cuticular surface with their tips.

(2) Body pubescence very sparse or absent, so that the entire cuticular surface is moderately to strongly shining. The appendages are densely covered with appressed hair, the legs somewhat more so than the scapes.

(3) Viewed from the side the crest of the petiole thin and acute; the entire posterior margin of the petiole feebly concave in each of the three specimens examined.

(4) Viewed in full face the genal margins nearly straight, curving inward only near the mandibular insertions. As a result the occipital region appears proportionately wider, and the entire head more sagittate, than in fuliginosus.

(5) The median clypeal keel, which is feebly developed in fuliginosus, is completely lacking in crispus.

HW of paratopotype 1.58 mm., of Ueda queen 1.55 mm., of Kochi City queen 1.52 mm.

Male
Wilson (1955) – description of synonym Lasius crispus: (1) In side view the anterior and posterior faces of the petiole taper equally to form a narrow, sharp crest. Otherwise very similar to fuliginosus.

(2) Terminal segments of maxillary palp highly variable in length as in other Dendrolasius, but showing no sign of ankylosis.

(3) Pygostyle and subgenital plate as in fuliginosus.

HW of paratopotype male 1.08 mm., of Ueda series 1.04-1.26 mm. Genitalia identical to that of fuliginosus.

References based on Global Ant Biodiversity Informatics

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