Nematus clitellatus Nematus trisignatus Nematus Pachynematus foveolatus Pachynematus truncatus Pachynematus extensicornis Checklist of British and Irish Hymenoptera - Sawflies, ' Symphyta' Liston, Andrew D. Knight, Guy T. Sheppard, David A. Broad, Gavin R. Livermore, Laurence Biodiversity Data Journal 2014 2 1168 1168 Serville, 1823 Serville 1823 Insecta Tenthredinidae Pachynematus CoL Animalia Pachynematus clitellatus Hymenoptera 0 1168 Arthropoda species clitellatus   Nematus clitellatusServille, 1823  Nematus trisignatus( Foerster, 1854, Nematus)  Pachynematus foveolatusKonow, 1903  Pachynematus truncatusBenson, 1948  Pachynematus extensicornis(Norton, 1861): misident.  Distribution England, Scotland, Wales, Ireland  Notes  Taeger and Blank (1998)regard Pachynematus clitellatusand Pachynematus fallaxas morphologically highly variable species, which together include most of the previously described W. Palaearctic taxa. Their arguments for this are well reasoned, but at present it seems prudent to continue to regard several of the more distinctive morphological segregates, treated as species by Benson (1958), as separate taxa, because morphologically intermediate specimens are rare (at least in the male sex). The taxonomy of the whole group requires further intensive work, including genetic analysis. According to Taeger and Blank (1998) Pachynematus kirbyi, treated here as valid, is a synonym of Pachynematus clitellatus.