Myrmica dongi, Chen, Zhilin, Zhou, Shanyi & Huang, Jianhua, 2016

Chen, Zhilin, Zhou, Shanyi & Huang, Jianhua, 2016, 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), ZooKeys 551, pp. 85-128 : 95-96

Taxon classification Animalia ORDO FAMILIA

Myrmica dongi sp. n. Figures 8-13

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.2009, No. G090156 ; 1 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.

Measurements and descriptions.

Holotype worker (Figs 8-10). HL 1.40, HW 1.25, FW 0.50, FLW 0.53, SL 1.15, PW 0.87, ML 1.75, PL 0.50, PH 0.45, ESL 0.40, CI 1.12, FI 0.40, FLI 1.06, SI1 0.82, SI2 0.92, ESLI 0.32. Paratype workers (n = 3). HL 1.30−1.41, HW 1.10−1.25, FW 0.48−0.50 FLW 0.50−0.53, SL 1.10−1.12, PW 0.82−0.90, ML 1.70−1.79, PL 0.42−0.51, PH 0.42−0.58, ESL 0.37−0.45, CI 1.13−1.17, FI 0.35−0.36, FLI 1.04−1.06, SI1 0.80−0.87, SI2 0.89−0.94, ESLI 0.27−0.34.

Paratype queen (Figs 11-13). HL1.25, HW 1.18, FW 0.53, FLW 0.55, SL 1.17, PW 0.95, ML 1.88, PL 0.5, PH 0.20, ESL 0.20, CI 1.06, FI 0.45, FLI 1.04, SI1 0.93, SI2 0.99, ESLI 0.17.

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 (SI2 = 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 45 º. 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.

Males. Unknown.

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 Myrmica 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 Myrmica 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.