On the taxonomy of Heterarthrus (Hymenoptera, Tenthredinidae), with a review of the West Palaearctic species

The sawfly genusHeterarthrusis naturally distributed in the Palaearctic, with a single described Oriental species. Their larvae mine in the leaves of trees and shrubs of Salicaceae, Betulaceae, and Sapindaceae (Acer). We here recognise twelve West Palaearctic species as valid, with the status of two additional nominal species group taxa in need of further study:fruticicolumErmolenko, andsmithiErmolenko. A key to adults of the species occurring in the West Palaearctic is presented. Two new species are described:Heterarthus vikbergiListon, Mutanen & Viitasaari,sp. nov.from females and males reared from leaf-mines inPopulus balsamiferacollected in eastern Finland, andHeterarthrus fioraListon,sp. nov.from females reared fromAcer pseudoplatanus. The latter is a widespread European species, previously misidentified asHeterarthrus aceris(Kaltenbach, 1856). New junior subjective synonyms arePhyllotoma acerisKaltenbach, 1856 ofHeterarthrus leucomela(Klug, 1818),H. aihinoensisHaris, 2006 ofH. kamtchaticus(Malaise, 1931) sp. rev., andH. imbrosensisSchedl, 1981 ofH. wuestneii(Konow, 1905). Lectotypes are designated forPhyllotoma flavicollisGussakovskij, 1947,P. kamtchaticaMalaise, 1931, andTenthredo ochropodaKlug, 1818.