Tapinoma erraticum

This is a small black ant, agile and aggressive on disturbance. Colonies usually contain several hundred workers and many queens. Nests are constructed under stones or in bare ground in dry sunny places and loose earth solaria for brood incubation are often constructed during the early summer. This species is partly aphidicolous and partly carnivorous. Alatae are developed in June with flights occurring during July (Collingwood 1979). Pashaei Rad et al. (2018) found this species in Iran on the ground in a moderate to low rainfall area.

Identification
Dark brown to black: head wedge shaped widening posteriorly; clypeus with median notch as wide as or wider than deep. Dorsum of alitrunk and appendages without standing hairs. Body covered with adpressed white pubescence and very finely punctured. Antennae 12 segmented, palp formula 6,4. Length: 2.6-4.2 mm. (Collingwood 1979)

Distribution
Throughout Central Europe from Spain to the Caucasus and from the mountains of South Italy to North Germany (Collingwood 1979).

Distribution based on Regional Taxon Lists
Palaearctic Region: Albania, Andorra, Armenia, Austria, Balearic Islands, Belarus, Belgium, Bulgaria, Canary Islands, Channel Islands, Croatia, Czech Republic, France, Georgia, Germany, Gibraltar, Greece, Hungary, Iberian Peninsula, Iran, Israel, Italy, Kazakhstan, Kyrgyzstan, Liechtenstein, Lithuania, Luxembourg, Malta, Monaco, Montenegro, Netherlands, Poland, Portugal, Republic of Macedonia, Republic of Moldova, Romania, Russian Federation, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Turkmenistan, Ukraine, United Kingdom of Great Britain and Northern Ireland, Åland Islands.

Biology
This ant has been associated with the butterfly Glaucopsyche alexis (Obregon et al. 2015).

Guiliani et al. (2019) observed this species foraging on extrafloral nectaries of the invasive Reynoutria x bohemica (Polygonaceae) in Tuscany. The habitats examined were river banks and disturbed habitats.

Nomenclature

 *  erraticum. Formica erratica Latreille, 1798: 44 (w.q.m.) FRANCE.
 * Wheeler, G.C. & Wheeler, J. 1951: 197 (l.).
 * Combination in Tapinoma: Mayr, 1855: 373; Smith, F. 1855a: 111.
 * Status as species: Latreille, 1802c: 182; Schenck, 1852: 67; Smith, F. 1855a: 111; Mayr, 1855: 373 (redescription); Nylander, 1856b: 71; Smith, F. 1858b: 55; Mayr, 1861: 41 (in key); Smith, F. 1861a: 34; Roger, 1863b: 13; Mayr, 1863: 455; Mayr, 1865: 62; Smith, F. 1871b: 2; Forel, 1874: 60 (in key); André, 1874: 185 (in key); Mayr, 1877: 11; Emery, 1878a: ix (in list); Emery, 1878b: 49; Emery & Forel, 1879: 454; Mayr, 1880: 30; Saunders, E. 1880: 210; André, 1881b: 63; André, 1882b: 222 (in key); White, W.F. 1884: 256; Forel, 1886e: clxvii; Forel, 1889: 256; Nasonov, 1889: 26; Forel, 1890a: lxviii; Saunders, E. 1890: 203; Emery, 1891b: 15; Forel, 1892i: 308; Lameere, 1892: 65; Dalla Torre, 1893: 164; Medina, 1893: 105; Forel, 1894d: 13; Forel, 1895d: 227; Saunders, E. 1896: 27; Ruzsky, 1902d: 19; Ruzsky, 1903b: 308; Ruzsky, 1905b: 473; Forel, 1906c: 189; Wasmann, 1906: 115 (in key); Forel, 1907e: 15; Forel, 1909c: 104; Bondroit, 1910: 489; Karavaiev, 1910b: 46; Karavaiev, 1911: 9; Forel, 1911d: 350; Karavaiev, 1912a: 15; Krausse, 1912b: 165; Emery, 1913a: 40; Stitz, 1914: 78; Forel, 1915d: 43 (in key); Emery, 1916b: 215; Wheeler, W.M. & Mann, 1916: 172; Escherich, 1917: 329; Bondroit, 1918: 89; Santschi, 1919e: 246; Menozzi, 1921: 32; Santschi, 1921a: 114; Soudek, 1922: 59; Müller, 1923b: 111; Lomnicki, 1925b: 2; Emery, 1925d: 53 (redescription); Wheeler, W.M. 1926: 4; Kuznetsov-Ugamsky, 1927d: 34; Donisthorpe, 1927b: 200; Lomnicki, 1928: 6; Kuznetsov-Ugamsky, 1929b: 42; Karavaiev, 1930b: 147; Soudek, 1931: 11; Zimmermann, 1935: 43; Karavaiev, 1936: 169; Novák & Sadil, 1941: 96 (in key); Kratochvíl, in Kratochvíl, et al. 1944: 79; Donisthorpe, 1950e: 1062; Consani & Zangheri, 1952: 42; Ceballos, 1956: 309; Bernard, 1956b: 259; Baroni Urbani, 1964a: 6; Baroni Urbani, 1964b: 55; Baroni Urbani, 1964c: 159; Bernard, 1967: 257 (redescription); Baroni Urbani, 1968b: 475; Baroni Urbani, 1971c: 159; Pisarski, 1975: 28; Tarbinsky, 1976: 123 (redescription); Aktaç, 1977: 124; van Boven, 1977: 125; Kutter, 1977c: 181; Arnol’di & Dlussky, 1978: 547 (in key); Collingwood, 1978: 87 (in key); Collingwood, 1979: 35; Barquin Diez, 1981: 357; Schembri & Collingwood, 1981: 421; Seifert, 1984a: 151; Agosti & Collingwood, 1987b: 279 (in key); Dlussky, Soyunov & Zabelin, 1990: 169; Atanassov & Dlussky, 1992: 192; Hohmann, et al. 1993: 159; Shattuck, 1994: 143; Arakelian, 1994: 73; Bolton, 1995b: 400; Czechowski, et al. 2002: 14; Radchenko, 2007: 38; Seifert, 2007: 256; Casevitz-Weulersse & Galkowsky, 2009: 478; Lapeva-Gjonova, et al. 2010: 32; Boer, 2010: 16; Legakis, 2011: 23; Borowiec, L. & Salata, 2012: 537; Czechowski, et al. 2012: 66; Seifert, 2012a: 144; Berville, et al. 2013: 84; Borowiec, L. 2014: 167 (see note in bibliography); Radchenko, 2016: 88.
 * Senior synonym of atomus: Roger, 1863b: 13; Mayr, 1865: 62; Forel, 1874: 99 (in list); Emery & Forel, 1879: 454; Emery, 1925d: 53.
 * Senior synonym of bononiensis: Atanassov & Dlussky, 1992: 192; Radchenko, 2016: 88.
 * Senior synonym of breve: Dlussky, Soyunov & Zabelin, 1990: 169; Radchenko, 2016: 88.
 * Senior synonym of caerulescens: Mayr, 1863: 455; Mayr, 1865: 62; Forel, 1874: 99 (in list); Emery & Forel, 1879: 454; Dalla Torre, 1893: 164; Emery, 1913a: 40.
 * Senior synonym of collina: Schenck, 1852: 67; Smith, F. 1855a: 111; Mayr, 1855: 373; Nylander, 1856b: 71; Smith, F. 1858b: 55; Mayr, 1863: 455; Roger, 1863b: 13; Mayr, 1865: 62; André, 1874: 202 (in list); Forel, 1874: 99 (in list); Emery & Forel, 1879: 454; Dalla Torre, 1893: 164; Ruzsky, 1905b: 473; Emery, 1913a: 40; Emery, 1925d: 53; Radchenko, 2016: 88.
 * Senior synonym of glabrella: Smith, F. 1855a: 111; Mayr, 1855: 373; Nylander, 1856b: 71; Smith, F. 1858b: 55; Mayr, 1863: 455; Roger, 1863b: 13; Mayr, 1865: 62; André, 1874: 202 (in list); Forel, 1874: 99 (in list); Emery & Forel, 1879: 454; Dalla Torre, 1893: 164; Ruzsky, 1905b: 473; Emery, 1913a: 40; Radchenko, 2007: 38; Radchenko, 2016: 88.
 * Senior synonym of tauridis: Dlussky, Soyunov & Zabelin, 1990: 169; Radchenko, 2016: 88.
 * Senior synonym of transcaucasica: Dlussky, Soyunov & Zabelin, 1990: 169; Radchenko, 2016: 88.
 * Current subspecies: nominal plus platyops.
 * atomum. Formica atomus Latreille, 1798: 44 (w.) FRANCE.
 * Combination in Tapinoma: Roger, 1863b: 13.
 * Subspecies of erraticum: Latreille, 1802c: 183 (in text); Emery, in Dalla Torre, 1893: 165; Emery, 1913a: 40; Bolton, 1995b: 399 (error).
 * Junior synonym of erraticum: Roger, 1863b: 13; Mayr, 1865: 62; Emery & Forel, 1879: 454; Emery, 1925d: 53.
 * caerulescens. Formica caerulescens Losana, 1834: 314, fig. 3 (w.) ITALY. Junior synonym of erraticum: Mayr, 1865: 62.
 * glabrella. Formica glabrella Nylander, 1849: 38 (footnote) (w.) RUSSIA. Junior synonym of erraticum: Smith, F. 1855a: 111; Mayr, 1855: 373; Radchenko, 2007: 38.
 * collina. Tapinoma collina Foerster, 1850a: 43 (w.q.) GERMANY. Junior synonym of erraticum: Schenck, 1852: 67.
 * bononiensis. Tapinoma erraticum var. bononiensis Emery, 1925d: 55 (w.q.) ITALY. Junior synonym of erraticum: Atanassov & Dlussky, 1992: 192.
 * breve. Tapinoma breve Emery, 1925d: 60, fig. 12 (w.) KAZAKHSTAN. Subspecies of erraticum: Kuznetsov-Ugamsky, 1927d: 34. Junior synonym of erraticum: Dlussky, Soyunov & Zabelin, 1990: 169.
 * tauridis. Tapinoma tauridis Emery, 1925d: 59, fig. 11 (w.q.m.) UKRAINE. Junior synonym of erraticum: Dlussky, Soyunov & Zabelin, 1990: 169. See also: Karavaiev, 1927d: 336.
 * transcaucasica. Tapinoma tauridis subsp. transcaucasica Karavaiev, 1927d: 337 (w.m.) KAZAKHSTAN. [First available use of Tapinoma simrothi subsp. karavaievi var. transcaucasica Karavaiev, 1926e: 187; unavailable name.] Junior synonym of erraticum: Dlussky, Soyunov, & Zabelin, 1990: 169.

Type Material
Seifert (2012) - A recent search conducted by J. Casevitz-Weulersse showed that there were no Tapinoma specimens in the Latreille collection of Muséum National d'Histoire Naturelle Paris (J. Casevitz-Weulersse, pers. comm. 13 June 2008). There is also no information that any of the taxonomists of the 20th century has ever seen an original specimen of Tapinoma erraticum. Hence, a complete loss of original material is highly probable or, at least, a reliable identification is impossible due to the useless original description and missing labelling of specimens. The presence of a minimum of seven Tapinoma species in Europe (SEIFERT 1984) and the fact that a safe identification of some species cannot be guaranteed for all future by descriptive statements and published information induces the need to fix a neotype. As the description of Latreille contains no diagnostic information, the neotype designation can only follow the rationale that (a) it should belong to the species widely considered as T. erraticum in Europe and (b) that the neotype comes as nearly as practicable from the original type locality. The locus typicus of T. erraticum is Brive-la-Gaillarde (France). I selected a neotype worker from a nest sample kindly collected by Christophe Galkowski about 11 km south from the city centre of Brive. The neotype is labelled "FRA: 45.0517°N, 1.5372°E, Nespouls-Faugère, 330 m, along road, under stone, leg. Galkowski 2008.07.02" and "Neotype Tapinoma erraticum (Latreille, 1798), design. B.Seifert 2010". It is stored in the collection of the Senckenberg Museum für Naturkunde Görlitz and has the following data: CS 836 μm, CL / CW 1.100, SL / CS 1.024, EL / CS 0.259, dAN / CS 0.279, ExCly / CS 8.87%, ExOcc / CS 1.42%, MGr / CS 3.58%, MW / CS 0.646 and ML / CS 1.347. Digital files with detailed z-stack photographs of the neotype in different positions are available on request from SMN Görlitz. There are 19 nestmate workers from the neotype nest in the collection of SMN Görlitz either mounted or stored in undenatured 99.8% ethanol.

Taxonomic Notes
Khalili-Moghadam et al. (2019) - A recent paper on Albanian ants by Wagner et al. (2018) suggested that southern populations from the Balkans recorded as Tapinoma erraticum represent a cryptic undescribed species. Parts of populations from areas east of the Balkans probably belong to the same cryptic taxon but prior to the formal description we applied the appellation T. erraticum to the Iranian populations.

Borowiec & Salata (2020): Wagner et al. (2018) suggest that southeastern populations of Tapinoma erraticum belong to an independent species named provisionally as Tapinoma sp. Balc. Both taxa differ mostly in subtle characters in male genitalia, the southern taxon is also slightly larger than true T. erraticum. We re-examined our materials from Greece and Bulgaria and confirmed that in this region occurs only Tapinoma sp. Balc. The only confirmed localities of true T. erraticum from Balkan Peninsula are from Croatia, Montenegro, North Macedonia and Slovenia. With great probability populations from Jordan belong to the undescribed species. However, we cannot exclude occurrence of another cryptic species from this group in this region.

Worker
Seifert (2012) - Head, mesosoma and gaster covered by a rather dense pubescence. With maximum head length and width in visual plane, posterior margin of head in medium-sized and large specimens slightly excavated. Anteromedian clypeal excision usually at least as deep a wide. Eye contours deviating from ideally elliptic form, showing linear sections on median margin. Anterior margin of clypeus with a few standing setae, the two longest based near to the anterolateral margin of clypeal excision. Remaining surface of head capsule and dorsal mesosoma without standing setae, such are present on mandibles, coxae and ventral surface of gaster. Head, mesosoma and gaster dark blackish brown. Antennae, femora and tibiae dark brown. Tarsi and distal end of tibiae light yellowish brown.

Male
Seifert (2012) - (see fig. 3 in Seifert 1984 for genital in ventral view): excision of the subgenital plate much shallower than in Tapinoma subboreale. The caudal tips of subgenital plate rounded, much shorter and much less distant than in T. subboreale. Stipal tips, in contrast, widely separate and caudally strongly surpassing the tips of subgenital plate which is completely invisible in dorsal aspect.