North-Western Palaearctic species of Pristiphora (Hymenoptera, Tenthredinidae)
Authors: Prous Marko , Kramp Katja , Vikberg Veli , Liston Andrew 
Published: February 2019

North-Western Palaearctic species ofPristiphoraLatreille, 1810 are revised. Altogether, 90 species are treated, two of which are described as new:P.caraganaeVikberg &amp; Prous,sp. n.from Finland andP.dedearaListon &amp; Prous,sp. n.from Germany. Host plant ofP.caraganaeisCaraganaarborescensLam.Pristiphoradasiphorae(Zinovjev, 1993) (previously known from East Palaearctic) andP.cadmaWong &amp; Ross, 1960 (previously known from North America) are recorded for the first time from Europe.NematusnigricansEversmann, 1847 [=Pristiphoranigricans(Eversmann, 1847),comb. n.],N.breviusculusEversmann, 1847 [=Euuramelanocephalus(Hartig, 1837)], andN.caudalisEversmann, 1847 [=E.caudalis(Eversmann, 1847),comb. n.] are removed from synonymy withP.pallidiventris(Fallén, 1808),N.paralellusHartig, 1840 [=P.paralella(Hartig, 1840),comb. n.] is removed from synonymy withP.bufo(Brischke, 1883), andP.mesatlanticaLacourt, 1976 is removed from synonymy withP.insularisRohwer, 1910. The following 29 new synonymies are proposed:P.nigropuncticepsHaris, 2002,syn. n.withP.albitibia(Costa, 1859);LygaeonematuskarvoneniLindqvist, 1952,syn. n.withP.alpestris(Konow, 1903); P. (P.) anivskiensis Haris, 2006,syn. n.withP.appendiculata(Hartig, 1837);NematuscanaliculatusHartig, 1840,syn. nwithP.carinata(Hartig, 1837);P.nigrogroenblomiHaris, 2002,syn. n.withP.cinctaNewman, 1837;TenthredoflavipesZetterstedt, 1838,syn. n.,NematuscongenerW.F. Kirby, 1882,syn. n., andP.thomsoniLindqvist, 1953,syn. n.withP.dochmocera(Thomson, 1871);P.atrataLindqvist, 1975,syn. n.withP.friesei(Konow, 1904);P.gelidaWong, 1968,syn. n.withP.frigida(Boheman, 1865);PachynematusnigricorpusTakagi, 1931,syn. n.withP.laricis(Hartig, 1837); Nematus (Pikonema) piceae Zhelochovtsev in Zhelochovtsev and Zinovjev, 1988,syn. n.and P. (P.) hoverlaensis Haris, 2001,syn. n.withP.leucopodia(Hartig, 1837);MesoneuraarcticaLindqvist, 1959,syn. n.,PachynematusincisusLindqvist, 1970,syn. n.,PachynematusintermediusVerzhutskii, 1974,syn. n., andP.mongololaricisHaris, 2003,syn. n.withP.malaisei(Lindqvist, 1952);NematusanderschiZaddach, 1876,syn. n.,P.inocreataKonow, 1902,syn. n., andP.discolorLindqvist, 1975,syn. n.withP.nigricans(Eversmann, 1847);LygaeonematustenuicornisLindqvist, 1955,syn. n.withP.paralella(Hartig, 1840);LygaeonematusconcolorLindqvist, 1952,syn. n.withP.pseudocoactula(Lindqvist, 1952);P.flavipictaLindqvist, 1975,syn. n.,P.flavopleuraHaris, 2002,syn. n.,P.mongoloexiguaHaris, 2002,syn. n., andP.mongolofaustaHaris, 2003,syn. n.withP.punctifrons(Thomson, 1871);P.listoniLacourt, 1998,syn. n.withP.sootryeniLindqvist, 1955;P.gaunitziLindqvist, 1968,syn. n.withP.testacea(Jurine, 1807); andNematusbreviusculusEversmann, 1847,syn. n.withEuuramelanocephalus(Hartig, 1837). The valid name of Pachynematus (Pikonema) carpathiensis Haris, 2001 isNematinuscarpathiensis(Haris, 2001)comb. n.Lectotypes are designated for 43 taxa. An illustrated electronic key made with Lucid and a traditional dichotomous key are provided to facilitate identification of the species. Species belonging to thecarinata(previouslyLygaeotus),micronematica(previouslyLygaeophora), andrufipes(also known asthalictrioraquilegiae) groups are not keyed to the species level, because additional research is needed to delimit the species more reliably in these groups. Phylogeny ofPristiphorais reconstructed based on one mitochondrial (COI) and two nuclear (NaK and TPI) genes. Remarkably, around 50–60% (depending on the exclusion or inclusion of thecarinata,micronematica, andrufipesgroups) of the species cannot be reliably identified based on COI barcodes. Limited data from nuclear genes indicate a better identification potential (about 20% remain problematic).