Myrmica angulinodis

A wood nesting boreal forest ant, it can also be found in high elevation clearings and glades.

Identification
Radchenko and Elmes (2010) - A member of the lobicornis species group. Female castes are characterised by i) a scape that is distinctly angled at its base (not gradually curved), without a vertical lobe or dent on the bend, ii) its sharply angled, subtriangular petiolar node. seen in profile, and iii) propodeal spines that curve inwards when viewed from above. By the last two features, M. angulinodis is similar to Myrmica forcipata, but the latter has at least a small vertical dent at the scape base. On the other hand, by the shape of scape M. angulinodis resembles Myrmica kamtschatica, but differs by its subtriangular petiolar node compared to the more rounded node of the latter.

Distribution
Siberia, from Kuznetsky Alatau until Pacific Ocean, Mongolia, N China, Korean Peninsula.

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

Biology
Radchenko and Elmes (2010) - A typical boreal species associated predominantly with different kinds of taiga forest (spruce, larch, fir, birch and mixed forests), preferring areas with a more open canopy and often living in clearings and glades; in some old forests it is one of the commonest ant species accounting for 60% of ant nests (see Berman et al. 2010 and references therein). In the north of its range M. angulinodis lives at lower altitudes, from about sea level to some hundred meters, preferring open south facing mesoxerophyous habitats that are relatively rare in the Kolyma region, where the largest colony excavated contained ca. 1700 workers and 30 queens (Berman et a\. 2010). In the Korean Peninsula it inhabits mountain forests and subalpine meadows at altitudes between 1100 and 2500 m a.s.l., where it builds nests in rotten wood and in soil, often under stones; on peat bogs it nests in moss mounds. A large series of > 80 nests were taken between 1999 and 2000 in northern Mongolia, at about 1000 m, by the Polish entomologist Michal Woyciechowski, who deposited representative nest series in the ELMES collection. About 80% ofthese series lived in mountain forest biotopes and ecotones between this forest and the herb-meadow biotopes found adjacent to rivers, and between forest and dry-steppe biotope at the other extreme (for description of these biotopes see Muehlenberg et al. 2000). In the first two habitats two thirds of nests were in rotten wood (usually tree stumps), and the remainder split between grass tussocks, soil and under stones; in the latter drier steppe-like ecotone only 15% of colonies nested in rotten wood, the majority nesting in soil or under stones. The remaining 20% of colonies were evenly split between the herb-meadow biotopes and riparian-woodland biotopes where they preferred to nest in rotten stumps or moss and grass tussocks. All these data show that M. angulinodis is principally a forest species that nests in rotten wood. Mating swarms were observed on a hilltop (c. 1050 m) on 10th and 12th August 1999, these swarms contained a mixture of M. angulinodis and Myrmica forcipata and a few Myrmica divergens.

Nomenclature

 *  angulinodis. Myrmica scabrinodis subsp. angulinodis Ruzsky, 1905b: 689 (w.q.) RUSSIA. Radchenko, 1994g: 84 (m.). Raised to species: Collingwood, 1962: 217; Collingwood, 1976: 302. Senior synonym of baikalensis: Radchenko, 1994g: 84; of incurvata: Radchenko, 2005b: 138. See also: Radchenko & Elmes, 2010: 89.
 * baikalensis. Myrmica saposhnikovi subsp. baikalensis Pisarski, 1969a: 228 (w.q.) RUSSIA. [First available use of Myrmica scabrinodis subsp. saposhnikovi var. baikalensis Karavaiev, 1931b: 28; unavailable name.] Junior synonym of angulinodis: Radchenko, 1994g: 84.
 * incurvata. Myrmica incurvata Collingwood, 1976: 301, figs. 1-3 (w.) NORTH KOREA. Junior synonym of angulinodis: Radchenko, 2005b: 138.

Etymology
Radchenko and Elmes (2010) - name from a combination of the Latin words angularis = angled and nodus = knot or lump, to describe its sharply angled petiolar node (seen in profile).