Seven species new to science and one newly recorded species of the ant genus Myrmica Latreille, 1804 from China, with proposal of a new synonym (Hymenoptera, Formicidae)

Abstract Seven new species of the genus Myrmica Latreille, 1804 are described from China: Myrmica dongi sp. n., Myrmica huaii sp. n., Myrmica liui sp. n., Myrmica mifui sp. n., Myrmica oui sp. n., Myrmica wangi sp. n. and Myrmica yani sp. n. Myrmica forcipata Karawaiew, 1931 is recorded from China for the first time, while Myrmica zhengi Ma & Xu, 2011 is synonymized with Myrmica luteola Kupyanskaya, 1990. Identification keys based on worker caste are provided to the Myrmica species of China and the pachei-group species of the Old World, respectively.


Introduction
Myrmica Latreille, 1804 is a large genus belonging to the family Formicidae, with 200 species and 12 subspecies known worldwide to date (Bolton 2014). Although there was confusion of the concept of the genus Myrmica before the start of the twentieth century (Nylander 1846a, 1846b, 1849, 1857, Curtis 1854, which led to the additions to the genus of numerous taxa that did not truly belong to Myrmica (Radchenko and Elmes 2010), the works by Finzi (1926), Santschi (1931) and Arnol'di (1934) clarified the genus definition. The first revision of the genus Myrmica was provided by Weber (1947Weber ( , 1948Weber ( , 1950, who paid most of his attention to the Nearctic species but presented a comprehensive synopsis of the Palearctic species as well. From then on, a series of revisions were devoted to the genus Myrmica in the subsequent decades (Sadil 1952, Yarrow 1955, Arnol'di 1970, 1976, Kutter 1970, 1973, Francoeur 1981, Kupyanskaya 1986a, 1986b, Bolton 1988, Seifert 1988, 2003, 2011, Czekes et al. 2013). Besides the efforts described above, a more extensive revisionary project was launched by Redchenko and his colleagues. Radchenko's interest was first focused on the Myrmica species of the central and eastern Palaearctic region (Radchenko 1994a−f, Radchenko et al. 1997), but soon extended to the Himalaya, south-east Asia and the whole Oriental region , 1999a, 1999b. With the cardinal revisions of more species groups (Radchenko and Elmes 2001a, 2003a, 2009a, 2009b, Radchenko et al. 2006) and regional faunistic investigations (Radchenko and Elmes 2001, 2002, 2003, 2009c, Radchenko et al. 2001, Elmes et al. 2001, Radchenko et al. 2006, Radchenko et al. 2008a, 2008b, Elmes and Radchenko 2009), many new species were described from the regions with poorly known Myrmica fauna (e.g. China, Korea, Vietnam, Turkey, Sicily etc.), and the taxonomy of Myrmica in the Old World culminated with the publication of the monograph by Radchenko and Elmes (2010), in which a total of 147 species were recognized, including five fossil species from the European late Eocene ambers. Stappen (2014) made a systemic evaluation on work of Radchenko and Elmes (2010) with some modifications, changes. On the basis of the work of Radchenko and Elmes (2010), further research was conducted in the Himalayan region (Bharti 2012a, 2012b, Bharti and Sharma 2011a, 2011b, 2011c, 2013, resulting in the discovery of nine new species in total. The first Chinese species of the genus Myrmica, i.e. M. tibetana Mayr, 1889, was described from Xizang. Ruzsky (1915) described eight species/subspecies and added M. smythiesii Forel, 1902 to the Xizang fauna. Further work was carried out on the Myrmica fauna of China by later authors (Viehmeyer 1922, Wheeler 1928, 1930a, Donisthorpe 1929, Santschi 1937, Eidmann 1941, Wu and Wang 1995, Tang et al. 1995, Xia and Zheng 1997, Collingwood and Heatwole 2000, Wei et al. 2001b, Chang and He 2001b, Zhou 2001, Zhou and Huang 2002, Xu 2002, Radchenko et al. 2001, Huang et al. 2004, Li et al. 2005, Tie and Xu 2004, Tie and Xu 2005, Zhou 2005, Zhou 2006, Radchenko et al. 2008, Wang et al. 2009, Radchenko and Elmes 2009a, Radchenko and Elmes 2010, Zhou and Qian 2010, Zhou 2013, and the sporadic results were summarized in several checklists (Wheeler 1930b, Wu 1941, Chou and Terayama 1991, Huang and Zhou 2007, Guenard and Dunn 2012. Meanwhile, nomenclatural changes were made in various revisionary works. In detail,  , M. sinica with M. excelsa (Radchenko et al. 2008), M. limanica with M. gallienii (Collingwood 1979), M. smythiesii exigua Ruzsky, 1915 was replaced with M. ruzskyana (Radchenko and Elmes 2010); the following four taxa were raised to species: M. smythiesii bactriana, M. margaritae serica, M. margaritae pulchella (Radchenko and Elmes 2010), M. rugosa arisana ; M. rubra khamensis (= M. ruginodis khamensis) was considered as incertae sedis in Myrmica (Radchenko and Elmes 2010); M. margaritae inornata Menozzi, 1941 was determined as nomen nudum (Bolton 1995); the records for China of M. gallienii (Wei et al. 2001b, Chang and, M. inezae , Wei et al. 2001b, M. jessensis (Wu andWang 1995, Wei et al. 2001b), M. lobicornis (Eidmann 1941, Wei et al. 2001b, M. margaritae (Eidmann 1941, Wu and Wang 1995, Zhou 2001, Wei et al. 2001b, M. smythiesi cachmiriensis (Eidmann 1941) and M. wesmaeli (Chang and He 2001b) were deemed misidentifications, so they were excluded from Chinese fauna (Radchenko and Elmes 2010). In terms of all taxonomic decisions above-mentioned, 46 Myrmica species are recognized from China so far and M. ruginodis khamensis was considered an unidentifiable taxon recently (Radchenko and Elmes 2010). However, there are at least 104 species found in the surrounding regions of China which may be recorded in China in the near future, indicating that the diversity of Myrmica in China is extremely high. The Myrmica fauna of China is still poorly known, and many more species certainly remain to be found.
In this paper, seven new and one newly recorded Myrmica species are described from China. Myrmica zhengi Ma & Xu, 2011 is considered as a junior synonym of M. luteola Kupyanskaya, 1990, leading to an increase of the known Chinese Myrmica species to 54.

Materials and methods
This study is based on the specimens deposited in the Insect Collection of Guangxi Normal University, Guilin, China. Digital images of the specimens were taken with a Nikon AZ100 microscope. All measurements are in millimeters. Standard measurements and indices are mostly defined by Radchenko and Elmes (2010):

Myrmica luteola
Differential diagnosis. As Radchenko and Elmes (2010) noted, this species is very easy to distinguish from all other Myrmica species due to its unique features, i.e. strongly reduced and simple non-pectinate spurs on the middle and hind tibiae, and somewhat developed ventral petiolar and postpetiolar processes. Moreover, the workers show another feature that very rarely occurs in Myrmica species: the base of the first gastral tergite is distinctly longitudinally striated. Ma and Xu (2011) described M. zhengi from Shaanxi perhaps without reading the papers by Kupyanskaya (1990) and Radchenko et al. (2003aRadchenko et al. ( , 2010. These three important references are also not cited by Ma & Xu, so that they missed the key features. After a careful comparison of the five workers paratype and one queen paratype of M. zhengi with the original morphological descriptions and the identified specimens of M. luteola by Prof. Alexander G. Radchenko (Museum and Institute of Zoology Polish Academy of Sciences, Poland), we found no differences between them; therefore, we propose M. zhengi as a junior synonym of M. luteola.  Kupyanskaya, 1990. worker (paratype) (G060078). 1 head in full-face view 2 body in profile view 3 spurs of hind tibiae 4 body in dorsal view.  39°00'25"N, 113°35'46"E, 1751m, 21.vi.2009. Differential diagnosis. This species is similar to M. angulinodis, but differs from the latter by the distinct, though not large, vertical lobe at the scape bend. This species was previously known only from south and east Siberia, Mongolia, but absent in the Russian far east. Herein this species is recorded from China for the first time. Type material. Holotype worker. Sejila Mountain, Linzhi County, Xizang Autonomous Region, 29°40'00"N, 94°23'08"E, 4200m, 14.vi.2009, leg. Shuang Zhao, No. G090156. Paratypes. 1 worker, 11.vi.20091 worker, 14.vi.2009, No. G090137;1 worker, 15.vi.2009, No. G090141;1 queen, 17.vi.2009, No. G090149; the locality and collector the same as holotype.

Myrmica forcipata
Measurements and descriptions. Holotype worker  Holotype worker. Head longer than broad, with very weakly convex sides, almost straight posterior margin and rounded posterior corners; anterior clypeal margin rounded, slightly prominent, not notched medially. Frontal carinae curved outwards to merge with the rugae that surround antennal sockets. Frons wide, frontal lobes not extended. Antennal scape relatively long (SI 2 = 0.92), slightly shorter than head width, gradually though distinctly curved at the base, without any trace of lobe or carina.
Mesosoma robust, promesonotum in profile view slightly convex, promesonotal suture in dorsal view indistinct. Metanotal groove distinct, wide, but shallow. Propodeal lobes rounded. Propodeal spines relatively short, straight, sharp, directly backwards at an angle of less than 45º. Petiole high, with very short peduncle; petiolar node in profile view cylindric, anterior surface concave, dorsum of node slightly convex, with a distinct broad dorsal plate, posterior surface steep. Postpetiole subglobular, with anterior and dorsal surfaces forming a regular arch. Spurs of middle and hind tibiae well-developed and pectinate. Frons with dense, fine, slightly sinuous, longitudinal rugae, number of rugae between frontal carinae level with the eyes ca. 20, posterior part of the head and its sides with fine reticulation, spaces between rugae sparsely superficially punctate, appearing more or less shiny and never dull. Clypeus with longitudinal rugae, spaces between them shiny. Frontal triangle smooth and shiny. Pronotal dorsum with reticulation, lateral sides longitudinally rugose-punctate. Mesonotal and propodeal dorsum with < 20 moderately coarse transverse sinuous rugae. Lower parts of mesopleura and lateral sides of propedeum with longitudinal rugae. Spaces between rugae on mesosoma with fine punctures, but appearing quite shiny. Petiole and postpetiole dull, densely punctate.
Head without subdecumbent pilosity at lateral margins, posterior margin with erect to suberect long hairs, genae with a few long hairs; dorsum of mesosoma with long hairs; petiole with 5−6 long hairs and a few short hairs. Antennal scapes and tibiae with subdecumbent hairs. Body colored blackish-brown, appendages somewhat lighter.
Paratype workers. With similar morphological characters as holotype, but in some individuals, color reddish-brown to yellowish-brown; petiole only with 3 long hairs.
Paratype queen. Queen generally similar to workers in the shape and sculpture of the head, frontal lobes, propodeal spines (which are more blunt at the apex), petiole and postpetiole. Mesosoma long and low, coarsely sculptured; anterior half of scutum with sinuous longitudinal rugae and reticulations; posterior half of scutum, scutellum and propodeal dorsum with coarse, slightly sinuous longitudinal rugae; pronotum with coarse irregular rugae and reticulations; mesopleura and lower part of propodeum with longitudinal rugose. Petiolar node and postpetiole dull, more coarsely rugose than in the worker, ground sculptures developed.
Habitat. Found foraging on the ground of alpine meadow at the altitudes of 3437m. Nesting site unknown. Etymology. The specific epithet is the last name of a famous Chinese artist in the Ming Dynasty, Qichang Dong. Differential diagnosis. This species belongs to the pachei group. The worker of this group is easily distinguished from other Myrmica species by a combination of the following characters: mesosoma dorsum at least partly with transverse rugosity; scape gradually though distinctly curved at the base, not angled, with no trace of lobe or carina. Anterior clypeal margin rounded or slightly prominent with no medial notch; petiole with a relatively short peduncle. Radchenko and Elmes (2001) once believed that this group was only found in Himalaya. However, following the recent examination of the Myrmica of China (Radchenko and Elmes 2009), they found out that the pachei group was much more diverse than previously expected. Before this study, this group contains 15 species. Radchenko and Elmes (2009) have made a good taxonomic revision and provided a key to the group based on workers. In this study, four new species of this group are described. Because the pachei-group is a sizeable species group and the sole function of a key is to allow taxa to be identified, a revised key is necessary for this group of species of the Old World. Accordingly, this key is given at the end of this paper, and distinguishing morphological characters between each species in the pachei group is obvious. It is easy to find that Myrmica dongi sp. n. is very similar to M. pleiorhytida Radchenko & Elmes, but differs from the latter by anterior surface of the petiole concave, dorsum of node with a distinct dorsal plate, slightly convex, posterior surface steep. Only the mesonotal dorsum with a fine transverse rugae, number of rugae on this area < 20, number of rugae between frontal carinae level the eyes ≤ 20.
This species is also closely related to M. dongi sp. n., but differs from the latter by petiole with a stronger triangular ventral process; propleuron with rugose; mesonotal and propodeal dorsum with about 20 moderately coarse transverse sinuous rugae. Holotype worker. Head longer than broad, with weakly convex sides and posterior margin, and broadly rounded posterior corners; anterior clypeal margin broadly rounded, shallowly notched medially. Frontal carinae very feebly curved, merging with the rugae that extend to the margin of the head. Frons wide, frontal lobes much extended. Antennal scape long (SI 2 0.94), slightly shorter than head width, gradually though distinctly curved at the base, with ridge on the inner margin.

Myrmica liui
Mesosoma in profile view weakly convex; promesonotal suture in dorsal view visible, metanotal groove very weak or absent. Propodeal lobes rounded. Propodeal spines short, blunt, directly backward and downward. Petiole with anterior surface concave, meeting the dorsal one to form a blunt angle, dorsum of node somewhat convex and steeply sloping backward, without dorsal plate. Postpetiole shorter than high, with convex dorsum. Spurs on middle and hind tibiae well-developed and pectinate.
Head with coarse longitudinal rugae on the whole dorsum, number of rugae between frontal carinae level with the eyes < 20. Posterior part and lateral sides of the head coarsely reticulated. Clypeus with coarse longitudinal rugae. Frontal triangle with a few longitudinal rugae, space between rugae shiny.
Dorsum and sides of mesosoma with less sinuous longitudinal rugae, space between rugae smooth and shiny. Petiole and postpetiole with short rugae, and densely punctate. Head with abundant, long, suberect hairs at lateral margins; dorsum of mesosoma with longer hairs, petiole with 6−8 long and some shorter hairs. Antennal scape and tibiae with subdecumbent hairs. Head and gaster colored dark brown, mesosoma reddish-brown, appendages lighter.
Paratype workers. As holotype. Queens and males. Unknown.
Habitat. This species nests in the soil in alpine meadow, at elevation 2573m. Etymology. The specific epithet is the Chinese name Gongquan Liu, who was a famous Chinese calligrapher in the Tang Dynasty.
Differential diagnosis. This species belongs to the lobicornis species group, which is one of the three most diverse species group of the Old World, containing 22 species (Radchenko and Elmes 2010). Radchenko and Elmes (2010) divided this group into five species complex, based on worker characters. This species shares features of kasczenkoi-complex of this group by mesosoma with less coarse sinuous longitudinal rugosity, propodeal spines shorter (ESLI ≤ 0.35), petiole of various shape, but never with well developed flattened dorsal plate. The kasczenkoi-complex includes 5 species: M. angulinodis, M. commarginata, M. displicentia, M. kamtschatica and M. kasczenkoi. M. liui sp. n. is similar to M. angulinodis, but the latter propodeal spines that curved inward when viwed from above. M. liui sp. n. is very similar to M. commarginata, but differs from the latter by dorsum of petiole somewhat convex and steeply sloping backward, without dorsal plate; on the other hand, the latter possesses unique morphological feature: mesonotum and propodeum are strongly conwtricted laterally, so that dorsal surface of them is narrow and form a sharp fidges, merging with the outer bases of propodeal spines. M. liui sp. n. also semblables to M. displicentia, but differs from the latter by dorsum of petiole without dorsal plate. This species is also similar to M. kasczenkoi Ruzsky, but differs from the latter by antennal scape with ridge at the base of the inner margin; propodeal spines thin, short, only 1/2 times longer than the distance between them, somewhat narrow at the base, backward and curved downward; petiole without dorsal plate. This species resembles to M. kamtschatica, but well differs from the latter by frontal carinae merges with the rugae that extend to the margin of the head, petiole without dorsal plate.
This species also is similar to M. sulcinodis Nylander of the sulcinodis-complex, but differs from the latter by sides of petiolar node with punctures and short rugae less coarse than those on the mesosoma. Metanotal groove very weak or absent. Anterior surface of petiole concave, meeting the dorsal one through a rounded angle, dorsum of node somewhat convex and steeply sloping backward. Holotype worker. Head longer than broad, with weakly convex sides and posterior margin, and narrowly rounded posterior corners; anterior clypeal margin relatively narrowly rounded, but not prominent and not notched medially. Frontal carinae very feebly curved, merging with the rugae that surround antennal sockets. Frons wide, frontal lobes not extended. Antennal scape relatively long (SI 2 = 1.00), equal to head width, gradually curved at the base, without any trace of lobe or carina.

Myrmica huaii
Mesosoma robust, promesonotum in profile view distinctly convex, promesonotal suture in dorsal view indistinct. Metanotal groove distinct, deep and abrupt. Propodeal lobes rounded. Propodeal spines straight, thin, acute, directly backward at an angle of approximately 30º. Petiole with distinct peduncle, anterior surface slightly concave, and dorsum of node broadly rounded, with a distinct dorsal plate. Postpetiole sub-globular, with anterior and dorsal surfaces forming a regular arch. Spurs of middle and hind tibiae well-developed and pectinate. Frons with dense, fine, slightly sinuous longitudinal rugae, number of rugae between frontal carinae level with the eyes > 25, posterior part and lateral sides of the head with fine reticulation, space between rugae dull, densely and coarsely punctate. Clypeus with longitudinal rugae, spaces between them shiny, frontal triangle smooth and shiny.
Pronotal dorsum reticulate, lateral sides reticulate-punctate. Mesonotal and propodeal dorsum each with more than ten moderately coarse sinuous transverse rugae. Lower parts of mesopleura and sides of propedeum with longitudinal rugae. Space between rugae on mesosoma with fine punctures, though appearing quite shiny. Petiole and postpetiole dull, densely punctate and reticulated. Anterior third of first gastral tergite with fine superficial hexagonal sculpture, the rest of the tergite smooth and shiny.
Head with short subdecumbent hairs at lateral margins above the eyes, posterior part of the head without additional long hairs, genae with a few long hairs; dorsum of mesosoma with long hairs; petiole with 4−6 long and a few short hairs. Antennal scape and tibiae with decumbent hairs. Gaster with short suberect hairs. Head and gaster blackish-brown, mesosoma yellowish-brown, appendages somewhat lighter.
Paratype workers. As holotype, but gaster with less short suberect hairs; petiole and postpetiole middle densely punctuate and the longitudinal rugae of frons more rough than holotype.
Queens and males. Unknown.
Habitat. Found foraging on the ground in coniferous forest at an altitude of 1927 m. Nesting site unknown.
Etymology. The specific epithet is the Chinese name Su Huai, who was a famous Chinese calligrapher in the Tang Dynasty.
Differential diagnosis. This species belongs to the pachei group. It is easy to find that this species is very similar to M. schulzi and M. phalacra, but differs from the latters two by basal third of first gastral tergite with fine superficial hexagonal sculpture; posterior margin without any erect to suberect long hairs; dorsum of petiolar node with a distinct broad dorsal plate. Main discriminative morphological characters with other species of the pachei-group is showed in the key of pachei-group species.  Holotype worker. Head longer than broad, with very weakly convex sides and almost straight posterior margin, and rounded posterior corners; anterior clypeal margin rounded, slightly prominent, not notched medially. Frontal carinae very feebly curved, merging with the rugae that extend to the posterior third dorsum of head. Frons wide, frontal lobes not extended. Antennal scape relatively long, gradually though distinctly curved at the base, without any trace of lobe or carina.

Myrmica mifui
Mesosoma relatively robust, promesonotum in profile view convex, promesonotal suture in dorsal view well-developed. Metanotal groove distinct, very deep. Propodeal lobes triangular apically. Propodeal spines moderately long, straight, sharp, directly backward at an angle of about 45º. Petiole high, with very short peduncle, its anterior surface slightly concave, dorsum of node with a distinct dorsal plate, slightly convex, posterior surface steep, so that petiolar node appears sharply cylindroid (seen in profile). Postpetiole subglobular, its anterior and dorsal surfaces forming a regular arch. Spurs of middle and hind tibiae well-developed and pectinate.
Head with very dense, fine, almost straight, slightly posteriorly diverging longitudinal rugae on the whole dorsum, number of rugae between frontal carinae level with the eyes < 25. Posterior part and lateral sides of the head with reticulation, surface between reticulation densely superficially punctate, appearing more or less shiny and not dull. Clypeus with longitudinal rugae, surface between them shiny. Frontal triangle smooth and shiny.
Pronotal dorsum reticulated, lateral sides reticulate-punctate; mesonotal dorsum with 8−10 coarse sinuous transverse rugae; dorsum of propodeum with several finer transverse rugae; lower parts of mesopleura and sides of propodeum with fine longitudinal rugae. Space between rugae on mesosoma smooth and shiny. Petiole high, and with a strongly triangular ventral process. Petiole and postpetiole with short irregular rugae, densely though not coarsely punctate, appearing dull.
Margins of head with long suberect hairs; dorsum of mesosoma with longer hairs, petiole with 6−8 long hairs. Antennal scape and tibiae with subdecumbent hairs. Body colored blackish-brown, appendages somewhat lighter.

Queens and males. Unknown.
Habitat. Found in mountain meadows at an altitude of 3020 m. Nesting site unknown.
Etymology. The specific epithet is the name of a famous calligrapher in the Northern Song Dynasty.
Differential diagnosis. This species belongs to the pachei group. It is easy to find that this species is very similar to M. pleiorhytida, but differs from the latter by number of rugae between frontal carinae level with the eyes ≤ 25; mesonotal and propodeal dorsum fine transverse rugae < 20. This species also very resemles to M. dongi sp. n., but differs from the latter by petiole with a finer triangular ventral process; propleuron only with densely punctuated; mesonotal and propodeal dorsum with 8−10 coarse sinuous transverse rugae. Main discriminative morphological characters with other species of the pachei-group is showed in the key of pachei-group species. Holotype worker. Head longer than broad, with very feebly convex sides, nearly straight posterior margin and broadly rounded posterior corners. Anterior clypeal mar-gin very feebly convex, notched medially. Frontal carinae curved, merging with the rugae that extend to the posterior third dorsum of head. Frons wide, frontal lobes not extended, but raised vertically (i.e. perpendicular to the surface of the head). Antennal scape relatively long (SI 2 1.21), longer than head width, gradually though distinctly curved at the base, without any trace of lobe or carina.
Mesosoma relatively short (compared to related species), promesonotal dorsum in profile view finely convex, promesonotal suture in dorsal view indistinct; mesonotum abruptly curved down to propodeum to form distinct, deep and wide metanotal groove. Propodeal lobes projecting to form short and blunt triangle. Propodeal spines relatively long, widened at the base, directly backward and downward. Petiole relatively long and narrow, with strongly concave of anterior surface, dorsum of node feebly convex, with distinct dorsal plate; postpetiole as shown in figures, slightly shorter than high.
Head with fine, almost straight, posteriorly diverging longitudinal rugae on the whole dorsum, eight rugae between frontal carinae level with the eyes. Posterior part and sides of the head without reticulations, spaces between rugae densely punctate, dull. Clypeus with longitudinal rugae, surface between rugae shiny. Frontal triangle smooth and shiny.
Dorsum of mesosoma with coarse reticulation, lateral sides with coarse sinuous longitudinal rugae. Lower part of mesopleuron and sides of propodeum with coarse longitudinal rugae. In dorsal view, dorsum of propodeal behind the metanotal groove with a distinct U-shaped coarse rugae (seen in Fig. 25). Petiole and postpetiole at most with very fine sculptures or short irregular rugae and dense, though not coarse, punctures and dull.
Head posterior margin with long suberect hairs; mesosoma dorsum with longer hairs, petiole with 6−8 long hairs. Antennal scape with suberect hairs. Tibiae with subdecumbent hairs. Head, gaster and petiole and postpetiole brownish-red, dorsum of head with some dark patches. Mesosoma black to blackish-brown.
Paratype workers. As holotype, but in one individual, petiole only with 4 long hairs.

Queens and males. Unknown.
Habitat. This species nests under litter layer and soil layer in the broadleaf forests, at elevation 1202m.
Etymology. The specific epithet is the last name of a famous Chinese artist in the Tang Dynasty, Yanxun Ou.
Differential diagnosis. This species belongs to the draco-complex of the ritae species group that includes M. draco, M. plodii, M. schoedli, M. yamanei. The workers of this species complex seems to be intermediate between the ritae-complex and boltonicomplex, but differs from the latter two by head dorsum and mesosoma rugose, petiole and postpetiole finely striated and punctuated, space of head dorsum between rugae punctuated. In terms of geography, M. oui sp. n. and M. draco may be occupying similar niches, but former differs from the latter by mesonotum abruptly curving down to the propodeum to form a distinct, deep and wide metanotal groove; in dorsal view, the dorsum of propodeum behind the metanotal groove bears a distinct U−shaped coarse ruga; first gastral tergite with clear superficial hexagonal microsculpture; body large (HW=1.38), dorsum of head with some dark patches. Given these obvious morphological differences, we are certain that M. oui sp. n. is not a variety of M. draco but an independent science species. Holotype worker. Head longer than broad, with very feebly convex sides, nearly straight posterior margin and broadly rounded posterior corners. Anterior clypeal margin very feebly convex, notched medially. Frontal carinae very feebly curved, merging with the rugae that extend to the posterior third dorsum of head. Frons wide, frontal lobes not extended, but raised vertically (i.e. perpendicular to the surface of the head). Antennal scape relatively long (SI 2 = 1.18), longer than head width, gradually though distinctly curved at the base, without any trace of lobe or carina.

Myrmica wangi
Promesonotal dorsum in profile view convex, promesonotal suture in dorsal view indistinct; mesonotum abruptly curved down to propodeum to form distinct, deep and wide metanotal groove. Propodeal lobes projecting to form short blunt triangle. Propodeal spines relatively long, widened at the base, directly backward and slightly downward. Petiole relatively short and wide, with anterior surface strongly concave, dorsum of node feebly convex; postpetiole somewhat shorter than high (Fig. 26).
Head with fine, almost straight, posteriorly diverging longitudinal rugae on the whole dorsum extending back to posterior margin, eight rugae between frontal carinae level with the eyes. Posterior part of the head with reticulations, space between rugae finely superficially micro−punctate. Clypeus with longitudinal rugae, space between them shiny. Frontal triangle smooth and shiny.
Dorsum of mesosoma with coarse reticulation, lateral sides with coarse sinuous longitudinal rugae. Petiole with coarse, short, sinuous longitudinal rugae, postpetiole with less coarse longitudinal, slightly sinuous rugae. Space on body between rugae smooth and shiny.
Posterior margin of head with up to two long suberect hairs; mesosoma dorsum with longer hairs, petiole with 1−6 long hairs. Antennal scape with suberect hairs. Tibiae with subdecumbent hairs. Head, gaster and petiole and postpetiole brownishred, mesosoma black to blackish-brown.
Paratype workers. As holotype. Queens and males. Unknown.
Habitat. This species nests inside decayed wood in the broadleaf and coniferous forests, at elevation 1667m.
Etymology. The specific epithet is the last name of a famous Chinese artist in the Eastern Jin Dynasty, Xizhi Wang. n.) of the ritae species group were found from Shaanxi Province, which is the highest latitude distribution areas of this species group in the Old world. We investigated the two paratypes workers of M. draco Radchenko, Zhou & Elmes found that two species are very similar to each other, but M. wangi sp. n. differs from the M. draco by the nearly straight posterior margin and broadly rounded posterior corners, frontal carinae extend back to posterior margin, posterior part of the head without reticulation; only posterior margins with 0−2 long suberect hairs; propodeal lobes projecting to form short and blunt triangle; petiole with coarse, short, sinuous longitudinal rugae, petiole and postpetiole with fewer punctures, appears shiny. On the other hand, This species is also similar to M. oui sp. n., but differs from the latter by the surface between rugae on the head with fewer punctures and appearing shiny. In dorsal view, dorsum of propodeum behind the metanotal groove with irregular coarse rugae. Petiole and postpetiole with coarse, short, sinuous longitudinal rugae, with fewer punctures, appearing shiny. We considered that these morphological differences is very obvious, which could be easily aparted from the other species of the genus Myrmica.   (Figs 29−31 Holotype worker. Head longer than broad, with weakly convex sides and posterior margin, and narrowly rounded posterior corners; anterior clypeal margin narrowly rounded, not notched medially. Frontal carinae very feebly curved, merging with the rugae that extend to the posterior half dorsum of head. Frons wide, frontal lobes not extended. Antennal scape relatively long (SI 2 1.27), gradually curved at the base, without any trace of lobe or carina.

Measurements and descriptions. Holotype worker
Promesonotum in profile view slightly convex, promesonotal suture in dorsal view indistinct. Metanotal groove distinct, deep and abrupt. Propodeal lobes rounded. Propodeal spines quite short, straight, thin, acute, directly backward at an angle of about 30º. Petiole with distinct, but short peduncle, anterior surface slightly convex, meeting the dorsal one to form a blunt, narrowly rounded angle, dorsal surface short, gradually sloping posteriorly, without dorsal plate. Postpetiole subglobular, anterior and dorsal surfaces forming a feeble arch. Spurs of middle and hind tibiae well-developed and pectinate. Frons with dense, fine, slightly sinuous longitudinal rugae, number of rugae between frontal carinae level with the eyes is >20; posterior third dorsum of head densely punctate; posterior part of the head densely micropunctate and dull. Clypeus almost smooth, at most with some fine longitudinal rugae, space between rugae shiny. Frontal triangle smooth and shiny.
Mesosoma with fine transverse rugae in the whole of dorsum, space between rugae with micropunctures and dull. Posterior of petiole with fine short rugae, the rest of petiole and postpetiole densely punctate, appearing dull.
Head with abundant long hairs at margins, genae with a few long hairs; dorsum of mesosoma with long hairs; petiole with 4−6 long hairs and a few short hairs. Antennal scape and tibiae with subdecumbent hairs. Body colored yellowish brown, appendages somewhat lighter.
Paratype workers. With similar morphological characters as holotype, but in one individual, dorsum of mesonotum and front part of pronotum of transverse rugae is abscure.
Paratype queen. Queen generally similar to workers by the shape and sculptures of head (except posterior dorsum of head with fine transverse rugae), frontal lobes, propodeal spines and petiole and postpetiole. Anterior half of scutum with sinuous longitudinal rugae and reticulation; scutum with coarse longitudinal rugae, scutellum concentrically rugulose, propodeal dorsum with transverse rugae; lateral of mesosoma with slightly less coarse longitudinal rugae. Petiolar node and postpetiole with some irregular rugae, space between rugae densely punctate, appearing dull.

Males. Unknown.
Habitat. This species nests inside decayed wood in the broadleaf and coniferous forests, at elevation 1667m.
Etymology. The specific epithet is the last name of a famous Chinese artist in the Tang Dynasty, Zhenqing Yan. Differential diagnosis. Myrmica yani sp. n. is a remarkable new species, belonging to the pachei group. So far, only three species (M. pachei, M. inezae and M. villosa) are recorded from the Himalayas which possess the key character of the whole mesosoma of dorsum bearing transverse rugae. Myrmica yani sp. n. differs from the M. pachei and M. inezae by having a distinctly elongated head, with narrowly rounded posterior corners; posterior third of head dorsally without longitudinal rugae and reticulation, but densely punctate; petiole with distinct, short peduncle, its anterior surface slightly convex, meeting the dorsal one to form a blunt, narrowly rounded angle; dorsal surface short, gradually sloping posteriorly; body colored yellowish brown. It differs from M. villosa by the distinctly elongated head, with narrowly rounded posterior corners; posterior third of head dorsally without longitudinal rugae, but densely punctate; propleuron with densely micropunctures and dull; dorsum of propodeum with fine transverse rugae; anterior surface of petiole slightly convex, meeting the dorsal one to form a blunt, narrowly rounded angle.

Key to Myrmica species found in China based on the worker caste
*The key is modified from Radchenko and Elmes (2010). Any doubtful species are excluded here; M. mixta is also excluded from the key because the worker caste is not well-known.

1
Lateral portion of clypeus raised into a sharp ridge in front of the antennal insertions, so that the antennal sockets are distinctly separated from the clypeal surface (similar to that of Tetramorium) (Radchenko and Elmes 2010: fig. 80, A) ....... 2 − Lateral portion of clypeus not raised into a sharp ridge in front of the antennal insertions, so that the antennal sockets lay on the same level with the clypeal surface (Radchenko and Elmes 2010: fig. 134, A) fig. 134, A). Antennal scape strongly curved or gradually curved at the base, with or without a lobe, ridge or carina (Radchenko and Elmes 2010: fig. 5, B;22, B;66, B;123, B;128, B;134, B-E;195, B;239, B-C;273, B-C;325, B-C