Formicoxenus.

[Teleutotje]

Formicoxenus Mayr, 1855
= Symmyrmica Wheeler, 1904, syn. by Francoeur, Loiselle, Buschinger, 1985

Formicoxenus nitidulus (Nylander, 1846)
= Myrmica nitidula Nylander, 1846
= Leptothorax nitidulus (Nylander, 1846), by ?[Wasmann, 1906]?
= Formicoxenus nitidulus (Nylander, 1846), by Mayr, 1855
= Myrmica laeviuscula Foerster, 1850
= Formicoxenus laeviuscula (Foerster, 1850), by Mayr, 1855, syn. by Mayr, 1855
= Myrmica lucidula F. Smith, 1857 nomen nudum, unavailable, referred here by Donisthorpe, 1915
= Leptothorax nitidulus var. picea Wasmann, 1906
= Formicoxenus nitidulus var. picea (Wasmann, 1906), by Emery, 1908, syn. by Francoeur, Loiselle, Buschinger, 1985

Formicoxenus sibiricus (Forel, 1899)
= Leptothorax sibiricus Forel, 1899
= Formicoxenus sibiricus (Forel, 1899), by Francoeur, Loiselle, Buschinger, 1985
= Formicoxenus orientalis Dlussky, 1963, syn. by Francoeur, Loiselle, Buschinger, 1985
= Leptothorax zhengi Zhou, Chen, 2011, in Zhou, Peng, Chen, Zhou, Liang, 2011, syn. by Seifert, 2023

Formicoxenus gebaueri Seifert, 2023

Formicoxenus hirticornis (Emery, 1895)
= Leptothorax hirticornis Emery, 1895
= Formicoxenus hirticornis (Emery, 1895), by Buschinger, 1979
= Leptothorax hirticornis var. formidolosus Wheeler, 1915
= Formicoxenus hirticornis var. formidolosus (Wheeler, 1915), by Buschinger, 1979, syn. by Smith, 1939

Formicoxenus provancheri (Emery, 1895)
= Leptothorax provancheri Emery, 1895
= Formicoxenus provancheri (Emery, 1895), by Francoeur, Loiselle, Buschinger, 1985
= Leptothorax emersoni Wheeler, 1901
= Formicoxenus emersoni (Wheeler, 1901), by Francoeur, Loiselle, Buschinger, 1985, syn. by Creighton, 1950
= Leptothorax emersoni subsp. hirtipilis Wheeler, 1917
= Formicoxenus emersoni subsp. hirtipilis (Wheeler, 1917), by Francoeur, Loiselle, Buschinger, 1985, syn. by Creighton, 1950
= Leptothorax emersoni subsp. glacialis Wheeler, 1907
= Formicoxenus emersoni subsp. glacialis (Wheeler, 1907), by Wheeler, 1910
= Formicoxenus provancheri subsp. glacialis (Wheeler, 1907), by Creighton, 1950, syn. by Cole, 1954

Formicoxenus chamberlini (Wheeler, 1904)
= Symmyrmica chamberlini Wheeler, 1904
= Formicoxenus chamberlini (Wheeler, 1904), by Francoeur, Loiselle, Buschinger, 1985

Formicoxenus diversipilosus (M. R. Smith, 1939)
= Leptothorax diversipilosus M. R. Smith, 1939
= Formicoxenus diversipilosus (M. R. Smith, 1939), by Buschinger, 1979

Formicoxenus quebecensis Francoeur, Loiselle, Buschinger, 1985

This is a complete list about the Formicoxenus species and their synomyms.

But now I come to a remark by Seifert, 2023. He was alluding to make synonyms of the genera Formicoxenus and Leptothorax. But then he decided that they are momentary still complete divided and should stay separate. But what if the division is blurred later on? Synonyms? But have a look at this:

Formicoxenus Mayr, 1855, valid, masculine.
Formicoxenus Mayr, 1855: 413. Type-species: Myrmica nitidula, by monotypy.

Leptothorax Mayr, 1855, valid, masculine.
Leptothorax Mayr, 1855: 431. Type-species: Formica acervorum, by subsequent designation of Bingham, 1903: 214.

Than it should become Formicoxenus. Will the Americans accept that?

[Teleutotje]

You have seen this in the list above? :

= Leptothorax zhengi Zhou, Chen, 2011, in Zhou, Peng, Chen, Zhou, Liang, 2011, syn. by Seifert, 2023

So, maybe a synonym for the genera?