Leptothorax muscorum

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Leptothorax muscorum
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Leptothorax
Species: L. muscorum
Binomial name
Leptothorax muscorum
(Nylander, 1846)

MCZ-ENT 001 Leptothorax muscorum hal.jpg

MCZ-ENT 001 Leptothorax muscorum had.jpg

Specimen Label


This species shows a preference for drier and warmer habitats (it does not inhabit bogs). In the mountains, it lives in meadows. Nests are built under small stones, under bark, in rotten wood, sometimes in litter. (Radchenko 2004)

At a Glance • Polygynous  



This is apparently a species complex and is in need of clarification. The clypeus of the worker is depressed in the middle and is without a medial carina, although several lateral carinae are present. The propodeal spines are well developed. The anterior face of the petiole is weakly concave, and meets the dorsum in an angle, the posterior face is convex and rounded. The dorsum and sides of the mesosoma, petiole and postpetiole are completely covered with punctate-granulose sculpture. There are numerous short (0.01mm), blunt-tipped hairs. (Mackay and Mackay 2002)

Pale brown to brown with antennal clubs and head often slightly darker. Propodeal spines short but distinct. General appearance more slender than Leptothorax acervorum. Head striate, mesosoma rugose and gaster smooth. Appendage hairs few and adpressed. Clypeus in some Scandinavian series have a distinct median concavity as described for Leptothorax gredleri Mayr (Buschinger, 1966) but they are not otherwise different from the typical species. Length: 2.4-3.2 mm (Collingwood 1979).


Appenines to Central Scandinavia and Pyrenees to Urals, not found in British Isles but common in continental Europe (Collingwood 1979). Northern North America.

Distribution based on Regional Taxon Lists

Nearctic Region: Canada, United States.
Neotropical Region: Mexico.
Palaearctic Region: Andorra, Armenia, Austria, Belarus, Belgium, Bulgaria, China, Croatia, Czech Republic, Denmark, Estonia, Finland (type locality), France, Georgia, Germany, Greece, Hungary, Iberian Peninsula, Kyrgyzstan, Latvia, Liechtenstein, Lithuania, Luxembourg, Mongolia, Montenegro, Netherlands, Norway, Poland, Republic of Moldova, Romania, Russian Federation, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


In Scandinavia, this species is restricted to sheltered valleys in woodland areas where it nests in stony banks, tree stumps or under bark. Its habits are similar to those of L. acervorum with small colonies having one or occasionally two queens. Males and alate queens are found in July and August.

Colonies of this species are found in dead Beargrass stems in Montana.

Wheeler and Wheeler (1986) - This small ant "is one of the very few truly boreal-alpine members of its family. It is known from a very wide area in the northern Palearctic" (Brown, 1955:43). "Of all ants occurring in North America, Leptothorax muscorum is the species best able to survive in extreme Arctic-alpine conditions. Throughout boreal and alpine North America within the limits of the timbered areas, L. muscorum is found in company with Camponotus herculeanus (Linnaeus) and Formica neorufibarbis Emery, the two dominant ants of the region" (Brown, 1955:47). Brown (p. 49) reported L. muscorum from an island at the mouth of the Mackenzie River, lat. 69°32'N, long. 133°47'W, which "seems to be the northernmost record for ants in the Western Hemisphere."

Colorado - Gregg (1963) reported this ant in Colorado from dry tundra and a variety of forest types; 5,345-12,000 ft.

New Mexico - This is one of the most common Leptothorax spp. in northern New Mexico. It nests in rotten logs (usually ponderosa pine) throughout the area. Logs may range from 15 cm to 1 m in diameter. Nests may also be located below stones. Brood and reproductives were found in the nests in July and August and nests may contain more than one queen. It shares nests with Myrmica fracticornis, Myrmica emeryana (=Myrmica latifrons) and Tapinoma sessile. (Mackay and Mackay 2002)

Nevada, Wheeler and Wheeler (1986) - We have 25 records from 18 localities 6,400-11,000 ft. Four records were in the Alpine Biome, 14 were in the Coniferous Forest. In the Alpine 1 nest was under a stone and 1 in dead wood; in the Coniferous Forest 7 nests were in and under rotten wood and 2 were in and under loose bark on dead trunks.

This species is a host for the slave-making species Harpagoxenus canadensis and Harpagoxenus sublaevis.






The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • muscorum. Myrmica muscorum Nylander, 1846b: 1054 (w.q.m.) FINLAND.
    • Combination in Leptothorax: Mayr, 1855: 439.
    • Combination in L. (Mychothorax): Ruzsky, 1904a: 288.
    • Subspecies of acervorum: Forel, 1874: 84 (in key); Emery & Forel, 1879: 458; Ruzsky, 1896: 72; Escherich, 1917: 328 (in key); Soudek, 1922: 50.
    • Status as species: Foerster, 1850a: 59; Mayr, 1855: 439 (redescription); Nylander, 1856b: 90; Smith, F. 1858b: 118; Mayr, 1861: 58 (in key); Roger, 1863b: 26; Mayr, 1863: 427; André, 1874: 189 (in key); André, 1883a: 294 (in key); Nasonov, 1889: 31; Dalla Torre, 1893: 125; Emery, 1895c: 318; Wheeler, W.M. 1901b: 519; Ruzsky, 1902d: 21; Ruzsky, 1903c: 207; Ruzsky, 1905b: 616; Wasmann, 1906: 119 (in key); Bondroit, 1910: 497; Karavaiev, 1912b: 582; Stitz, 1914: 62; Forel, 1915d: 26 (in key); Karavaiev, 1916: 503; Wheeler, W.M. 1917a: 511; Bondroit, 1918: 121; Bondroit, 1920a: 153; Müller, 1923b: 88 (in key); Emery, 1924d: 262; Menozzi, 1925d: 33; Lomnicki, 1928: 5; Karavaiev, 1931e: 212; Karavaiev, 1934: 145 (redescription); Novák & Sadil, 1941: 89 (in key); Novák, in Kratochvíl, Novák & Šnoflák, 1944: 112; Röszler, 1950: 225; Brown, 1955a: 47; Bernard, 1956a: 161; Buschinger, 1966b: 165; Francoeur & Béique, 1966: 142; Bernard, 1967: 200 (redescription); Pisarski, 1969a: 229; Pisarski, 1969b: 297; Dlussky & Pisarski, 1970: 86; Baroni Urbani, 1971c: 99; Pisarski, 1975: 23; Aktaç, 1977: 122; van Boven, 1977: 101; Kutter, 1977c: 130; Collingwood, 1978: 83 (in key); Arnol'di & Dlussky, 1978: 543 (in key); Wheeler, G.C. & Wheeler, J. 1978: 391; Collingwood, 1979: 72; Smith, D.R. 1979: 1397; Pisarski & Krzysztofiak, 1981: 157; Espadaler & Collingwood, 1982: 41; Allred, 1982: 484; Kupyanskaya, 1986b: 96; Wheeler, G.C. & Wheeler, J. 1986g: 53; Agosti & Collingwood, 1987b: 273 (in key); Nilsson & Douwes, 1987: 60; Loiselle, et al. 1990: 323; Kupyanskaya, 1990: 139; Atanassov & Dlussky, 1992: 132; Arakelian, 1994: 55; Radchenko, 1994b: 111 (in key); Radchenko, 1994d: 147 (in key); Douwes, 1995: 89; Bolton, 1995b: 241; Radchenko, 1995a: 25; Czechowski, et al. 2002: 42; Mackay & Mackay, 2002: 129; Radchenko, 2004: 130; Coovert, 2005: 79; Seifert, 2007: 225; Radchenko, 2007: 31; Zryanin & Zryanina, 2007: 231; Casevitz-Weulersse & Galkowski, 2009: 488; Lapeva-Gjonova, et al. 2010: 20; Boer, 2010: 50; Legakis, 2011: 16; Borowiec, L. & Salata, 2012: 510; Czechowski, et al. 2012: 132; Borowiec, L. 2014: 99; Radchenko, 2016: 210.
    • Senior synonym of betulae: Radchenko, 1995a: 25; Radchenko, 2016: 210.
    • Senior synonym of canadensis: Brown, 1955a: 47; Radchenko, 2016: 210.
    • Senior synonym of fagi: Radchenko, 1995a: 25; Radchenko, 2016: 210.
    • Senior synonym of flavescens: Radchenko, 1995a: 25; Radchenko, 2016: 210.
    • Senior synonym of kincaidi: Brown, 1955a: 47; Radchenko, 2016: 210.
    • Senior synonym of obscurus: Brown, 1955a: 47; Radchenko, 2016: 210.
    • Senior synonym of septentrionalis: Brown, 1955a: 47; Radchenko, 2016: 210.
    • Senior synonym of sordidus: Brown, 1955a: 47; Radchenko, 2016: 210.
    • Senior synonym of yankee: Brown, 1955a: 47; Radchenko, 2016: 210.
    • Material of the unavailable name “uvicensis” referred here.
  • flavescens. Leptothorax muscorum var. flavescens Ruzsky, 1896: 72 (w.) RUSSIA. [First available use of Leptothorax acervorum subsp. muscorum var. flavescens Ruzsky, 1895: 26; unavailable name.] Subspecies of muscorum: Ruzsky, 1905b: 621. Junior synonym of muscorum: Radchenko, 1995a: 25.
  • canadensis. Leptothorax canadensis Provancher, 1887: 245 (w.q.m.) CANADA. Wheeler, G.C. & Wheeler, J. 1955b: 21 (l.). Combination in L. (Mychothorax): Emery, 1924d: 261; in L. (Leptothorax): Wheeler, G.C. & Wheeler, J. 1955b: 21. Subspecies of acervorum: André, 1887: 295; Wheeler, W.M. 1903c: 225. Status as species: Emery, 1895c: 318; Creighton, 1950a: 274. Material of the unavailable name convivialis referred here by Creighton, 1950a: 276. Junior synonym of muscorum: Brown, 1955a: 47.
  • obscurus. Leptothorax canadensis subsp. obscurus Viereck, 1903: 72 (w.) U.S.A. Junior synonym of yankee: Creighton, 1950a: 277.
  • yankee. Leptothorax (Leptothorax) canadensis var. yankee Emery, 1895c: 319 (w.q.) U.S.A. Wheeler, W.M. 1917a: 513 (m.); Wheeler, G.C. & Wheeler, J. 1955b: 21 (l.). Subspecies of canadensis and senior synonym of obscurus, sordidus: Creighton, 1950a: 277. Junior synonym of muscorum: Brown, 1955a: 47.
  • betulae. Leptothorax muscorum var. betulae Ruzsky, 1916: 6 (w.) RUSSIA. Subspecies of muscorum: Ruzsky, 1936: 94. Junior synonym of muscorum: Radchenko, 1995a: 25.
  • fagi. Leptothorax (Mychothorax) muscorum var. fagi Ruzsky, 1905b: 619, fig. 151 (w.) CAUCASUS. Junior synonym of muscorum: Radchenko, 1995a: 25.
  • septentrionalis. Leptothorax (Mychothorax) muscorum var. septentrionalis Wheeler, W.M. 1917a: 511 (w.q.m.) CANADA. Material of the unavailable name calderoni referred here by Creighton, 1950a: 276. Junior synonym of muscorum: Brown, 1955a: 47.
  • sordidus. Leptothorax muscorum var. sordidus Wheeler, W.M. 1903c: 224, pl. 12, fig. 2 (w.) U.S.A. Junior synonym of yankee: Creighton, 1950a: 277.
  • kincaidi. Leptothorax yankee var. kincaidi Pergande, 1900: 520 (w.q.) U.S.A. Junior synonym of muscorum: Brown, 1955a: 47.



  • n = 17, 2n = 34 (Canada; Germany; USA) (Buschinger et al., 1980; Fischer, 1987; Loiselle et al., 1990) (possible variation due B chromosomes).
  • n = 18, 2n = 36 (Canada; Germany; USA) (Fischer, 1987; Loiselle et al., 1990) (possible variation due B chromosomes).
  • n = 22, 2n = 44 (Canada; Germany; USA) (Fischer, 1987) (possible variation due B chromosomes).
  • n = 23 (Canada; USA) (Loiselle et al., 1990) (possible variation due B chromosomes).
  • n = 16 (Canada; USA) (Loiselle et al., 1990).


  • André, E. 1883a. Les fourmis. [part]. Pp. 281-344 in: André, Edm. 1881-1886. Species des Hyménoptères d'Europe et d'Algérie. Tome Deuxième. Beaune: Edmond André, 919 + 48 pp. (page 294, Status as species)
  • Atanassov, N.; Dlussky, G. M. 1992. Fauna of Bulgaria. Hymenoptera, Formicidae. Fauna Bûlg. 22: 1-310 (page 132, see also)
  • Baroni Urbani, C. 1971c. Catalogo delle specie di Formicidae d'Italia (Studi sulla mirmecofauna d'Italia X). Mem. Soc. Entomol. Ital. 50: 5-287 (page 99, see also)
  • Brown, W. L., Jr. 1955a. The ant Leptothorax muscorum (Nylander) in North America. Entomol. News 66: 43-50 PDF (page 47, Senior synonym of canadensis, kincaidi, septentrionalis and yankee (and its junior synonyms obscurus and sordidus))
  • Buschinger, A. 1966c. Leptothorax (Mychothorax) muscorum Nylander und Leptothorax (M.) gredleri Mayr zwei gute Arten. Insectes Soc. 13: 165-172 (page 165, see also)
  • Collingwood, C. A. 1979. The Formicidae (Hymenoptera) of Fennoscandia and Denmark. Fauna Entomol. Scand. 8: 1-174 (page 72, see also)
  • Forel, A. 1874. Les fourmis de la Suisse. Systématique, notices anatomiques et physiologiques, architecture, distribution géographique, nouvelles expériences et observations de moeurs. Neue Denkschr. Allg. Schweiz. Ges. Gesammten Naturwiss. 26: 1-452 (page 84, Race of acervorum)
  • Forel, A. 1915d. Fauna insectorum helvetiae. Hymenoptera. Formicidae. Die Ameisen der Schweiz. Mitt. Schweiz. Entomol. Ges. 12(B Beilage: 1-77 (page 26, Combination in L. (Mychothorax))
  • Higgins, R. J. and B. S. Lindgren. 2015. Seral changes in ant (Hymenoptera: Formicidae) assemblages in the sub-boreal forests of British Columbia. Insect Conservation and Diversity. 8:337-347. doi:10.1111/icad.12112
  • Kupyanskaya, A. N. 1990a. Ants of the Far Eastern USSR. Vladivostok: Akademiya Nauk SSSR, 258 pp. (page 139, see also)
  • Kutter, H. 1977c. Hymenoptera, Formicidae. Insecta Helv. Fauna 6: 1-298 (page 130, see also)
  • Loiselle, R.; Francouer, A.; Fischer, K.; Buschinger, A. 1990. Variations and taxonomic significance of the chromosome numbers in the Nearctic species of the genus Leptothorax (s.s.) (Formicidae: Hymenoptera). Caryologia 43: 321-334 (page 323, see also)
  • Mayr, G. 1855. Formicina austriaca. Beschreibung der bisher im österreichischen Kaiserstaate aufgefundenen Ameisen, nebst Hinzufügung jener in Deutschland, in der Schweiz und in Italien vorkommenden Arten. Verh. Zool.-Bot. Ver. Wien 5: 273-478 (page 439, Combination in Leptothorax)
  • Mackay, W. P. and E. Mackay. 2002. The ants of New Mexico (Hymenoptera: Formicidae). Edwin Mellen Press, Lewiston, NY.
  • Nylander, W. 1846b. Additamentum adnotationum in monographiam formicarum borealium Europae. Acta Soc. Sci. Fenn. 2 2: 1041-1062 (page 1054, worker, queen, male described)
  • Radchenko, A. 2004. A review of the ant genera Leptothorax Mayr and Temnothorax Mayr (Hymenoptera, Formicidae) of the Eastern Palaearctic. Acta Zoologica Academiae Scientiarum Hungaricae 50(2): 109-137 (page 130, fig. 40 see also)
  • Radchenko, A. G. 1995a [1994]. A review of the ant genus Leptothorax (Hymenoptera, Formicidae) of the central and eastern Palearctic. Communication 1. Subdivision into groups. Groups acervorum and bulgaricus. Vestn. Zool. 1994 6: 22-28 (page 25, Senior synonym of betulae, fagi and flavescens)
  • Ruzsky, M. 1905b. The ants of Russia. (Formicariae Imperii Rossici). Systematics, geography and data on the biology of Russian ants. Part I. Tr. Obshch. Estestvoispyt. Imp. Kazan. Univ. 38(4-6 6: 1-800 (page 616, Status as species)
  • Smith, D. R. 1979. Superfamily Formicoidea. Pp. 1323-1467 in: Krombein, K. V., Hurd, P. D., Smith, D. R., Burks, B. D. (eds.) Catalog of Hymenoptera in America north of Mexico. Volume 2. Apocrita (Aculeata). Washington, D.C.: Smithsonian Institution Press, pp. i-xvi, 1199-2209. (page 1397, see also)
  • Wheeler, G. C. and J. Wheeler. 1986. The ants of Nevada. Natural History Museum of Los Angeles County, Los Angeles.