Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae)

Within the Formicidae, the higher classification of nearly all subfamilies has been recently revised given the findings of molecular phylogenetics. Here, we integrate morphology and molecular data to holistically address the evolution, classification, and identification of the ant genus Lasius, its tribe Lasiini, and their subfamily Formicinae. We find that the crown Lasiini originated around the end of the Cretaceous on the Eurasian continent and is divisible into four morphologically distinct clades: Cladomyrma, the Lasius genus group, the Prenolepis genus group, and a previously undetected lineage we name Metalasius gen.nov., with one extant species M. myrmidon comb. nov. and one fossil species, †M. pumilus comb. nov. The crown of the Lasius genus group is considerably younger than that of the Prenolepis genus group, indicating that extinction has played a major role in the evolution of the former clade. Lasius itself is divided into two well‐supported monophyletic groups, which are approximately equally speciose. We present evidence that temporary social parasitism and fungiculture arose twice independently in Lasius. In addition, we recover the paraphyly of three Lasius subgenera and propose replacing all subgenera with an informal species group classification: Lasius = Acanthomyops syn.rev., = Austrolasius syn.nov., = Cautolasius syn.nov., = Chthonolasius syn.nov., = Dendrolasius syn.nov. Total‐evidence analysis reveals that the Baltic‐region amber fossil species †Lasius pumilus and †Pseudolasius boreus are misplaced to genus; we, therefore, create Sussuido gen. nov. to accomodate †S. boreus comb. nov. and transfer †L. pumilus to Metalasius. Further, we transfer †Sussudio and †Glaphyromyrmex out of the Lasiini, considering the former to be incertae sedis in the subfamily, and the latter a member of the Formicini (tribal transfer). Two final taxonomic actions are deemed necessary: synonymy of Lasius escamole with Liometopum apiculatum syn.nov. (subfamilial transfer), and transfer of Paratrechina kohli to Anoplolepis (tribal transfer, forming A. kohli comb.nov.). ZooBank Article LSID: urn:lsid:zoobank.org:pub:016059BA‐33C3‐43B2‐ADAD‐6807DC5CB6D8 Author ZooBank LSIDs: Borowiec: urn:lsid:zoobank.org:author:411B711F‐605B‐4C4B‐ABDB‐D4D96075CE48. Boudinot: urn:lsid:zoobank.org:author:919F03B0‐60BA‐4379‐964D‐A56EB582E16D. Prebus: urn:lsid:zoobank.org:author:1A6494C7‐795E‐455C‐B66F‐7F6C32F76584