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

This key is based on: Radchenko, A.G. & Elmes, G.W. 2010. Myrmica ants of the Old World. Fauna Mundi 3: 1-789. The first key is a key to workers.

1

 * Lateral portion of clypeus raised into sharp ridge in front of antennal insertions, so that antennal sockets are distinctly separated from clypeal surface (similar to that of Tetramorium ) . . . . . 2


 * Lateral portion of clypeus not raised into sharp ridge in front of antennal insertions, so that antennal sockets lay on the same level with clypeal surface . . . . . 3

2
return to couplet #1
 * Scape at the bend having the same width as at its mid-length (seen in profile); the foot of scape having a longitudinal groove and lateral ridges (seen anteriorly). Males: petiole and postpetiole with fine superficial microsculpture, appearing dull. - Southern part of Russian Far East, north-eastern China, Korean Peninsula, Japan . . . . . Myrmica excelsa


 * Scape at the bend is distinctly narrower than at its mid-length (seen in profile); the foot of scape without longitudinal groove and lateral ridges (seen anteriorly). Males: petiole and postpetiole smooth, appearing shiny. – South Siberia (including Altai Mts.), southern part of Russian Far East, north-eastern China, Korean Peninsula, Japan (Hokkaido) . . . . . Myrmica transsibirica

3
return to couplet #1
 * Frontal carinae curved outwards to merge with the rugae that surround the antennal sockets. Scape very smoothly curved at the base, not angled and without any trace of lobe or carina . . . . . 4


 * Frontal carinae merging with the rugae that extend to the occipital margin, they do not curve outwards and do not merge with rugae that surround the antennal sockets. Scape strongly curved at the base, with or without a lobe, ridge or carina . . . . . 7

4
return to couplet #3
 * First gastral tergite finely but distinctly longitudinally striated at the base. Much more hairy species; petiolar node with ca. 10 long and numerous shorter standing hairs. Frons with numerous, fine longitudinal rugulae, numbering ≥ 20 between the frontal carinae level with the eyes. Spurs on tibiae of middle and hind legs reduced, simple (not pectinate). Scape quite strongly curved at the base. Queens no bigger than the workers, their propodeum without spines, at most with bunt tubercles. Males: scape short, SI2 < 0.50. - Southern part of Russian Far East, north-eastern China, Korean Peninsula, Japan . . . . . Myrmica luteola


 * First gastral tergite completely smooth. Less hairy species, petiolar node with 6-8 long standing hairs. Frons with fewer relatively coarse, longitudinal rugae, numbering ≤ 15 between the frontal carinae level with the eyes. Spurs on tibiae of the middle and hind legs well developed and pectinate. Scape gently curved at the base. Queens distinctly larger than the workers, their propodeum with spines. Males: scape long, SI2 > 0.70 . . . . . 5

5
return to couplet #4
 * Petiolar node with rounded dorsum, completely without a dorsal plate, node of petiole and postpetiole smooth, at most very finely striated; propodeal spines short, mean ESLI 0.26. - Europe, Caucasus, West Siberia, northern Kazakhstan, Tien-Shan, Pamir, East Siberia, to the east till Transbaikal region . . . . . Myrmica rubra


 * Petiolar node with a dorsal plate developed to various extents, node of petiole and post petiole with coarser sculpture, rugulose or rugose; propodeal spines longer, species' means ESLI 0.41 . . . . . 6

6
return to couplet #5
 * Petiolar node with a distinct, sharp flattened dorsal plate and having quite coarse short sinuous longitudinal rugae on lateral parts. Males: clypeus usually smooth, at most with very fine superficial punctures. – Transpalaearctic species, distributed from Atlantic to Pacific Oceans, including Japan, Caucasus, absent in Tien-Shan . . . . . Myrmica ruginodis


 * Petiolar node dorsum slightly convex, with somewhat convex, not sharp dorsal plate, laterally with finer short longitudinal rugulae. Males: clypeus with fine longitudinal striation. - Southern part of Russian Far East, northeastern China, Korean Peninsula, Japan . . . . . Myrmica kotokui

7
return to couplet #3
 * Scape sharply angled at the base, with horizontal lobe. - Europe, Caucasus, Asia Minor, northern Kazakhstan, West Siberia; the easternmost confirmed localities - vicinity of Krasnoyarsk (ca. 93°E) and 100 km N of Kansk (ca. 96°E) . . . . . Myrmica scabrinodis


 * Scape of various shapes, but never with horizontal lobe . . . . . 8

8
return to couplet #7
 * Scape sharply angled at the base, with a vertical lobe (that can be inclined anteriorly) or with dent . . . . . 9


 * Scape gradually curved or angled at the base, but never with a vertical or inclined lobe or dent . . . . . 17

9
return to couplet #8
 * Propodeal spines thick and blunt at their apex, directed backwards and upwards, and strongly curved inward; petiole with very short peduncle, its anterior surface steep and meets the dorsal one at an acute angle, so that petiolar node appears sharply angled (seen in profile). - East and South Siberia, to the west WI Saiany Mts., northern Mongolia; in Russian Far East is absent . . . . . Myrmica forcipata


 * Propodeal spines thin and sharp at their apex, not curved inward; petiole of various shapes (seen in profile) but if it is sharply angled, the frons is narrower (FI < 0.32 vs > 0.35 in M. forcipata) . . . . . 10

10
return to couplet #9
 * Lobe at the base of scape forms shield-like plate along the surface of the foot of the scape. Males: scape short, S11 < 0.50 . . . . . 11


 * Lobe at the base of scape does not form shield-like plate along surface of the foot of the scape. Males: scape long, SI1 > 0.60 . . . . . 13

11
return to couplet #10
 * Frontal carinae feebly curved, frons wider, FI > 0.33 (mean 0.35), and importantly the frontal lobes are not extended, FLl < 1.25. Scape with a small vertical dent. - Japan . . . . . Myrmica onoyamai


 * Frontal carinae strongly curved, frons narrower, FI < 0.33 (species' means < 0.30), and the frontal lobes are distinctly extended, FLI ≥ 1.50. Scape with larger, more distinct, not dentiform, vertical lobe . . . . . 12

12
return to couplet #11
 * Frontal carinae strongly curved, frons quite narrow, FI 0.20-0.27, mean 0.23. Scape lobe quite large and metanotal groove deeper. - Europe, Caucasus, West Siberia, northern Kazakhstan, Tien-Shan, East Siberia, to the east till Enisei river . . . . . Myrmica schencki


 * Frontal carinae less curved, frons wider, FI 0.27-0.32, mean 0.29. Scape lobe smaller and metanotal groove shallower. - West Siberia, to the west till Irtysh river, Tarbagatai and Saur Mts., South and East Siberia, Mongolia, southern part of Russian Far East, northern China, Korean Peninsula . . . . . Myrmica koreana

13
return to couplet #10
 * Petiole with a short peduncle, its anterior surface (seen in profile) is steep, only slightly concave, meeting the dorsal one to form an acute or right angle; dorsal plate distinct, declined posteriorly. Frons narrower and frontal lobes more extended, mean FI 0.28, mean FLI 1.43. - Boreal species: Europe, Caucasus, Asia Minor, Siberia, northern Kazakhstan, to the east till Transbaikal region . . . . . Myrmica lobicornis


 * Petiole of other shapes. Frons wider and frontal lobes less extended, species' means FI ≥ 0.32, means FLI < 1.40 . . . . . 14

14
return to couplet #13
 * Anterior surface of petiole (seen in profile) weakly concave and meeting the dorsal one to form a slightly rounded obtuse angle, node dorsum slightly convex, quite long and gradually sloping posteriorly, forming regular low arch together with the posterior surface; propodeal spines not widened at the base, slightly curved down and directed mainly backward, subhorizontal. - South Siberia, Mongolia . . . . . Myrmica pisarskii


 * Anterior surface of petiole (seen in profile) distinctly concave, node dorsum with convex plate or widely rounded, posterior surface steep; propodeal spines widened at the base, straight, directed backward and upward, not subhorizontal . . . . . 15

15
return to couplet #14
 * Scape at the base with a large lobe that is inclined anteriorly. - Altai Mts. and Southern Ural . . . . . Myrmica zojae


 * Scape at the base with small, almost vertical, lobe or dent . . . . . 16

16
return to couplet #15
 * Frontal carinae strongly curved, frons narrower, and frontal lobes more extended: FI 0.31-0.34, mean 0.32, FLI 1.29-1.42, mean 1.35. - Korean Peninsula, Japan . . . . . Myrmica jessensis


 * Frontal carinae less curved, frons wider, and frontal lobes less extended: FI 0.32-0.39, mean 0.36, FLI 1.18-1.40, mean 1.29. - South Siberia (from Buryatia in the west), Mongolia, Russian Far East, northern China, Korean Peninsula . . . . . Myrmica eidmanni

17
return to couplet #8
 * Mesonotum and propodeum strongly constricted laterally (seen from above), their dorsal surface narrow and delineated laterally by sharp ridges, which merge with the outer bases of the propodeal spines. - South and East Siberia, Mongolia . . . . . Myrmica commarginata


 * Mesonotum and propodeum not constricted laterally, their dorsal surface not delineated by ridges (i.e. of "normal" shape) . . . . . 18

18
return to couplet #17
 * Petiole with a distinct lobe-like subtriangular ventral process, its peduncle very short, anterior surface almost straight and steep, node narrowly rounded so that in profile, the petiole appears to be subtriangular. Scape short, mean SI1 0.70. Spur on the tibiae of hind and middle legs fairly reduced, short, often not pectinate. Males: antennae with 12 segments, scape short SI1 < 0.40. - South Siberia from Tuva to Transbaikalia, Mongolia . . . . . Myrmica arnoldii


 * Petiole of various shapes, but never with lobe-like ventral process. Scape longer, species' means SI1 > 0.75. Spur on hind and middle tibiae well developed and pectinate. Males: antennae with 13 segments, antennal scape of various length . . . . . 19

19
return to couplet #18
 * Scape gradually curved at the base or at most very slightly angled, usually without a ridge on the inner margin of its foot; if in some specimens such a ridge is present then the alitrunk and waist have very coarse, straight (not sinuous) longitudinal rugae, the petiole has a relatively short peduncle and its anterior surface is almost straight, meeting the dorsal one at a right angle, also the dorsal plate is developed, flattened, not inclined posteriorly (see M. sulcinodis, below) . . . . . 20


 * Scape distinctly angled at the base, always with ridge on the inner margin of its foot; if in some specimens the scape is not distinctly angled then the petiole has a very short peduncle and its anterior surface meets the dorsal one at an acute angle, so that petiolar node appears sharply angled . . . . . 25

20
return to couplet #19
 * Alitrunk with very coarse, straight (not sinuous) longitudinal rugae; propodeal spines long, often longer than the length of the propodeal dorsum, species' means ESLI ≥ 0.40; petiole with a short peduncle, seen in profile its anterior surface is almost straight, meeting the dorsal one almost at a right or somewhat obtuse angle, dorsal plate well developed, flattened, not inclined posteriorly. Scape strongly curved at the base, occasionally slightly angled . . . . . 21


 * Alitrunk with less coarse sinuous longitudinal rugosity (except for M. kasczenkoi); propodeal spines shorter, species' means ESLI < 0.35; petiole of various shapes, but never with a well developed, flattened dorsal plate. Scape gradually, often smoothly, curved at the base, never angled . . . . . 22

21
return to couplet #20
 * Sides of petiolar node with coarse rugae that are very similar to those on the alitrunk; anterior surface of petiole very steep, meeting the dorsal one almost at a right angle; propodeal spines somewhat shorter than the length of the propodeal dorsum, mean ESLI 0.40. - Boreal species, distributed from Ireland to Kamchatka, absent in Japan . . . . . Myrmica sulcinodis


 * Sides of petiolar node with coarse punctures and short rugae, which are much less coarse than those on the alitrunk; anterior surface of petiole less steep, meeting the dorsal one at a somewhat obtuse angle; propodeal spines very long, equal or longer than the length of the propodeal dorsum, mean ESLI 0.44. – Southern part of Russian Far East, Korean Peninsula . . . . . Myrmica ademonia

22
return to couplet #20
 * Sides of alitrunk with quite coarse, almost straight longitudinal rugae, metanotal groove very weak or absent; petiole and post petiole with longitudinal rugosity only, not punctated; anterior surface of petiole weakly concave and meets with dorsal one at a slightly rounded obtuse angle, node dorsum slightly convex, quite long and gradually sloping posteriorly, forming with posterior surface regular low arch. - Altai Mts., South Siberia, southern and southeastern Transbaikalia, Mongolia . . . . . Myrmica kasczenkoi


 * Alitrunk with less coarse sinuous longitudinal rugosity, metanotal groove distinct, often deep (except for M. kurokii); petiole and postpetiole with fine, short rugulae or striae, surface between them punctated; anterior surface of petiole distinctly concave, node dorsum rounded, posterior surface steep . . . . . 23

23
return to couplet #22
 * Bigger species: HW > 1.15, AL > 1.90. Surface of head dorsum between rugae densely punctated, appearing dull. Propodeal spines longer, mean ESLI 0.36. - Southern part of Russian Far East, northern China, Korean Peninsula, Japan . . . . . Myrmica kurokii


 * Smaller species: HW < 1.10, AL < 1.80. Surface of head dorsum between rugae at most very finely superficially micropunctated, appearing shiny. Propodeal spines shorter, species' means ESLI < 0.30 . . . . . 24

24
return to couplet #23
 * Anterior clypeal margin simply convex, not-notched medially. Males: scape short, SI1 < 0.40. - South and East Siberia (to the west - until Altai Mts.), Mongolia . . . . . Myrmica divergens


 * Anterior clypeal margin shallowly notched medially. Males: scape long, SI1 > 0.70. - Kamchatka, Magadan Provo of Russia . . . . . Myrmica displicentia

25
return to couplet #19
 * Petiole with very short peduncle, mean PI1 1.03, its anterior surface steep, very weakly concave, meeting the dorsal one at a sharp acute angle, dorsal plate flat, well developed, strongly inclined backward; propodeal spines usually curved inward. - Siberia, to the west till Kuznetsky Alatau, Russian Far East, Mongolia, north-eastern China, Korean Peninsula . . . . . Myrmica angulinodis


 * Petiole longer, with well developed peduncle, species' means PI1 1.20 ... 1.21, its anterior surface not steep, distinctly concave, meeting the dorsal one to form a slightly rounded acute or obtuse angle, dorsal plate not developed, node dorsum rounded or somewhat convex and steeply sloping backward; propodeal spines straight, never curved inward . . . . . 26

26
return to couplet #25
 * Anterior surface of petiole meeting the dorsal one to form slightly rounded obtuse angle, node dorsum widely rounded. Males: antennae with 13 segments. - South and East Siberia, Mongolia, Russian Far East, North Korea . . . . . Myrmica kamtschatica


 * Anterior surface of petiole meeting the dorsal one to form a rounded acute angle, node dorsum somewhat convex and steeply sloping backwards. Males: antennae with 12 segments. - East Siberia . . . . . Myrmica tschekanovskii