Myrmica koreana

M. koreana inhabits mainly steppes and steppe-like habitats both on planes and mountains up to 1700 m a.s.l., only rarely it has been found living in light deciduous and mixed forests. Nests are normally built in soil, with no obvious indication of the nest entrance other than small woven entrance funnels, these are very similar to, but perhaps somewhat shorter than those of M. schencki. Nuptial flights are in August-September. (Radchenko and Elmes 2010)

Identification
Radchenko and Elmes (2010) - A member of the schencki group. It most resembles Myrmica schencki. Female castes differ from the latter by their distinctly wider frons and much less extended frontal lobes; queens are considerably smaller than those of all other known queens of the schencki-group species. Males differ from those of M. schencki by their shorter and much less curved scape.

Key to Myrmica of species of East Siberia, Russian Far East, Mongolia, Korean Peninsula, northern China, and Japan

Distribution
South-eastern part of West Siberia, northeastern Kazakhstan (to the south until Saur Range), South Siberia, Mongolia, Russian Far East, northeast of China and Korea.

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

Nomenclature

 *  koreana. Myrmica koreana Elmes, Radchenko & Kim, 2001: 108, figs. 1a-d (w.) SOUTH KOREA. Radchenko, Elmes & Alicata, 2006: 521 (q.m.). See also: Seifert, 2003b: 153; Radchenko & Elmes, 2010: 169.

Worker
The head is slightly longer than broad (suboval), with strongly convex sides, a straight or slightly convex occipital margin, and very broadly rounded occipital corners; anterior clypeal margin is shallowly but distinctly notched medially. The frons is quite narrow (< 0.30 headwidth); frontal carinae are strongly curved and do not merge with the rugae which surrounded the antennal sockets, generally these rugae are reduced to a trace and are barely visible. The antennal scapes are relatively long and sharply bent at their bases (almost at right angles), with a small vertical lobe; the 3rd-5th funicular joints are about 1.5 times longer than broad.

In profile, the alitrunk dorsum forms a somewhat flattened arch; metapleural groove very shallow; promesonotal suture indistinct (seen from above); metapleural lobes angulate posterodorsally, but not pointed; propodeal spines are long, straight and sharp (they do not appear broadened at their bases) projecting backwards and upwards at just less than 45 degrees to the horizontal. The petiole is relatively low (height distinctly < length) with a short but distinct peduncle; seen in profile the anterior surface of petiole is distinctly concave, forming a rounded right angle where it meets the dorsal surface, while the posterio-dorsal surface forms a shallow, but somewhat angulate arch. The postpetiole is subglobular, relatively low and wide; in profile its ventral surface slopes backwards and appears almost straight, its posterio-dorsal surfaces form a slightly angulate arch with the apex close to the posterior. The hind and middle tibiae have large pectinate spurs.

The mandibles finely longitudinally rugulose; the frons and clypeus longitudinaly rugose, with the central part of clypeus having reduced rugosity; remainder of head dorsum coarsely reticulated; surfaces between the rugae are finely punctured but appear more or less shiny; frontal area and clypeus appear smooth and shiny. The alitrunk has coarse, sinuous rugosity on its dorsum and straight longitudinal rugae on its sides; petiole and postpetiole have coarse longitudinal rugae (some straight and some sinuous). The surfaces of the alitrunk and waist finely punctured but appear shiny (like head dorsum); gaster smooth and shiny. The whole body has abundant thin, straight or slightly curved, erect to suberect hairs; those of the occipital and lateral margins of head and scapes being suberect, those of the legs being subdecumbent. The overall colour is yellowish; alitrunk and waist testaceous yellow, and the head and gaster yellowish red.

Queen
Radchenko, Elmes and Alicata (2006) - Generally like workers in shape of head and scape, colour and pilosity of the body except they have coarser sculpture, especially on the alitrunk, petiole and postpetiole, and propodeal spines that are wider at their base and shorter. They are small (mean HW 1.02 mm) even relative to the workers, which are small for schencki-group species (mean HW 1.01 mm).

Male
Radchenko, Elmes and Alicata (2006) - Head slightly longer than broad, with convex sides and occipital margin, and gradually rounded occipital corners; anterior clypeal margin widely rounded and notched medially. Scape short but longer than 1st and 2nd funicular segments together, feebly curved though with distinctly angled dorsal plane. Antennae 13-segmented, with 5-segmented club.

Alitrunk quite long, scutum convex, scutellum does not projeet dorsally above scutum when seen in profile. Propodeum with blunt rounded tubercles. In profile, petiole relatively long and low, with narrowly rounded dorsum of node, its anterior surface almost straight but not steep; postpetiole higher than long, with weakly convex dorsum.

Head dorsum densely punctured and with very fine striation. Scutum and scutellum longitudinally rugulose, only anterior part of scutum finely striated. Propleura smooth and shiny, only with fine striation on their posterior parts; mesopleura and propodeum not coarsely rugose. Petiole finely striated, postpetiole smooth and shiny.

Head margins with very long curved standing hairs, alitrunk and waist with shorter hairs. Tibiae and tarsi with short subdecumbent to suberect hairs; scape and first 7 funicular segments with longer hairs, segments of antennal club with very short subdecumbent hairs. Body colour black, appendages somewhat lighter.

Type Material
Holotype, worker, [K-100 (9)], S. Korea, unknown location, in pitfall traps, leg. B.-J. Kim. Paratypes: 13 workers [K-100 (1-8, 9-14)] same series as holotype; 1 worker [K-99 (1)] S. Korea, Gechon-ri, nr. Pyongchang, Pyong chang-gun. In pitfall traps c.1970, leg. B.-J. Kim; 4 workers (1 no gaster) [K-115 1{no gaster], 4, 5, 7)] S. Korea, mountains, locality not known, leg. B.-J. Kim; 1 worker [K-122 (1)], S. Korea, mountains, locality not known, leg. B.-J. Kim; 7 workers [K-118 (2, 5, 7-11)], S. Korea, Sunchon City, 300 m. in soil. 2.vii.1959, leg. B. Pisarski & J. Proszyski, Inst. Zool. P.A.N. Warszawa 58/59. (, BMNH, KIM,, MILZ).

Etymology
Radchenko and Elmes (2010) - named for Korea where we believed it to be endemic when we first described it, however since then it has bee1n shown to be widespread in Siberia and the Far East.