Myrmica elbrusi

A mountain species, found on subalpine meadows, on floodplains of rivers, on edges of mixed forests (pine, birch) at altitudes 2070–2130 m. Nests were built in the soil, often under stones. It is currently only known from type material.

Identification
The main diagnostic features of workers and queens of M. elbrusi are: the scape smoothly curved at the base, with no trace of the lobe or carina; the frontal carinae very feebly curved, merging with the rugae that extend to the posterior margin, not curved outwards and not merged with the quite coarse rugae that surround antennal sockets; the anterior clypeal margin distinctly prominent, narrowly rounded and not-notched medially; the frontal carinae feebly curved, frons wide, and the frontal lobes not extended.

By the combination of these features, M. elbrusi does not fit to any species-groups of Myrmica (sensu Radchenko and Elmes 2010), known to occur in the Euro-Caucasian region, and it clearly differs from any Myrmica species from this region that have curved scapes.

Distribution based on Regional Taxon Lists
Palaearctic Region: Russian Federation.

Nomenclature

 *  elbrusi. Myrmica elbrusi Radchenko & Yusupov, 2012: 594, figs. 1-9 (w.q.) RUSSIA.

Worker
Measurements (in mm): (n = 18), ordered as: holotype (min-max) [mean ± SD]: HL = 1.18 (1.08–1.27) [1.17 ± 0.058], HW = 1.00 (0.88–1.07) [0.98 ± 0.057], FW = 0.48 (0.41–0.49) [0.46 ± 0.026], FLW = 0.50 (0.43–0.53) [0.49 ± 0.033], SL = 0.90 (0.81–0.94) [0.88 ± 0.043], AL = 1.65 (1.46–1.81) [1.62 ± 0.109], PNW = 0.73 (0.62–0.77) [0.70 ± 0.044], HTL = 0.90 (0.78–0.95) [0.87 ± 0.053], PL = 0.50 (0.42–0.52) [0.47 ± 0.035], PW = 0.32 (0.27–0.34) [0.31 ± 0.022], PH = 0.40 (0.34–0.40) [0.38 ± 0.025], PPL = 0.34 (0.31–0.38) [0.34 ± 0.020], PPW = 0.47 (38–0.47) [0.44 ± 0.035], PPH = 0.43 (0. 38–0.46) [0.42 ± 0.027], ESL = 0.28 (0.17–0.30) [0.25 ± 0.039], ESD = 0.44 (0.36–0.47) [0.42 ± 0.032].

Indices: CI = 1.18 (1.18–1.25) [1.20 ± 0.020], FI = 0.48 (0.45–0.49) [0.47 ± 0.011], FLI = 1.03 (1.03–1.10) [1.07 ± 0.017], SI1 = 0.77 (0.73–0.78) [0.75 ± 0.013], SI2 = 0.90 (0.88–0.92) [0.90 ± 0.012], PI1 = 1.25 (1.02–1.33) [1.26 ± 0.038], PI2 = 0.49 (0.44–0.51) [0.48 ± 0.016], PPI1 = 0.78 (0.77–0.86) [0.82 ± 0.032], PPI2 = 0.93 (0.92–1.00) [0.95 ± 0.026], PPI3 = 1.44 (1.33–1.48) [1.42 ± 0.045], PPI4 = 0.47 (0.42–0.47) [0.45 ± 0.018], ESLI = 0.27 (0.18–0.29) [0.25 ± 0.029], ESDI = 1.60 (1.50–2.15) [1.75 ± 0.198], HTI = 0.90 (0.85–0.97) [0.89 ± 0.025].

Head somewhat longer than broad, with distinctly convex sides, slightly convex occipital margin, and broadly rounded occipital corners; anterior clypeal margin distinctly prominent, narrowly rounded, not notched medially. Upper lateroventral corners of head rounded, not pointed (seen in profile). Eyes situate somewhat in front of the midlength of sides of head. Mandibles with 6–7 teeth. Frontal carinae very feebly curved, merged with rugae that extend to posterior margin, not curved outwards and not merged with the rugae that surround antennal sockets; frons wide, frontal lobes not extended. Scape relatively short, shorter than head width, smoothly curved at the base with no trace of lobe or carina.

Mesosoma with slightly convex promesonotal dorsum (seen in profile), promesonotal suture indistinct (seen from above). Metanotal groove distinct. Propodeal lobes rounded apically. Propodeal spines of moderate length, very feebly widened at the base, straight, thin and sharply pointed at the tips. Petiole with distinct peduncle, longer than high, its anterior surface strongly concave and quite steep; node dorsum sharply truncated, with distinct, slightly declined posteriorly dorsal plate; postpetiole distinctly higher than long. Spurs on middle and hind tibiae well developed and pectinate.

Frons with not numerous, quite coarse and somewhat sinuous longitudinal rugae, their number between frontal carinae level with the eyes less than 20; remaining parts of head dorsum with coarse sinuous rugosity and reticulation, clypeus with quite coarse longitudinal rugae. Surface of head between rugae appearing shiny; frontal triangle smooth and shiny; mandibles longitudinally rugulose.

Pronotal dorsum with longitudinal sinuous rugae and reticulation; mesonotal and propodeal dorsum with almost straight longitudinal rugae; sides of pronotum, mesopleura and sides of propodeum with almost straight longitudinal rugae. Surface between rugae appears shiny. Petiolar node dorsum with short sinuous rugae and reticulation, dorsum of postpetiole with longitudinal rugosity, surface between rugae appears shiny. Gaster smooth and shiny. Occipital and lateral margins of head with suberect hairs of moderate length. Mesosoma and waist with long erect and suberect hairs. Scape and tibiae with subdecumbent pilosity.

Mesosoma and waist brownish-red, head dorsum brown, gaster dark brown; appendages reddish.

Queen
Measurements (in mm): (n = 1): HL = 1.26, HW = 1.05, FW = 0.49, FLW = 0.53, SL = 0.91, AL = 2.13, AH = 1.04, SCW = 0.92, SCL = 1.34, HTL = 0.94, PL = 0.61, PW = 0.36, PH = 0.46, PPL = 0.42, PPW = 0.57, PPH = 0.53, ESL = 0.21, ESD =0.55; CI = 1.20, FI = 0.47, FLI = 1.07, SI1 = 0.72, SI2 = 0.86, PI1 = 1.34, PI2 = 0.58, PPI1 = 0.78, PPI2 = 0.93, PPI3 = 1.58, PPI4 0.54, ESLI = 0.20, ESDI = 2.63, AI =2.05, SCI = 1.45.

Generally like worker, except for its larger size (ca. 20%), structure of the alitrunk, presence of ocelli and much shorter propodeal spines.

Type Material
Holotype worker, North Caucasus, Russia, Kabardino-Balkaria, basin of river Chegem, gorge of river Bashil’ – Auzusu, right bank of river Basil’, 43°20’N, 42°98’E, alt. 2070 m a.s.l., No. 29, 22.06.2009, leg. Z. Yusupov, on ground (ZMMU); paratypes: 9 workers, 1 queen, same label as holotype; 3 workers, North Caucasus, Russia, Kabardino-Balkaria, basin of river Chegem, gorge of river Bashil’ – Auzusu, flood-lands, pitfall traps, 43°21’N, 42°98’E, alt. 2103 m a.s.l., No. 36, 22.06.2009, leg. A. Ayidov; 7 workers, North Caucasus, Russia, Kabardino-Balkaria, basin of river Chegem, gorge of river Bashil’ – Auzusu, right bank of river Basil’, 43°20’N, 42°98’E, alt. 2080 m a.s.l., No. 37, 22.06.2009, leg. Z. Yusupov, under stone; 1 worker, North Caucasus, Russia, Kabardino-Balkaria, gorge Adylsu, No. 34, 05.07.2003, subalpine meadow, leg. Z. Yusupov (IEMT, ZMMU, SIZK).

Etymology
Name derived from the mountain region of Elbrus, where the species was found.

References based on Global Ant Biodiversity Informatics

 * Borowiec L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
 * Dubovikoff D. A., and Z. M. Yusupov. 2018. Family Formicidae - Ants. In Belokobylskij S. A. and A. S. Lelej: Annotated catalogue of the Hymenoptera of Russia. Proceedingss of the Zoological Institute of the Russian Academy of Sciences 6: 197-210.