Checklist of british and irish hymenoptera - sawflies, 'symphyta'.

Abstract

The superfamilies Cephoidea, Orussoidea, Pamphilioidea, Siricoidea, Tenthredinoidea, Xiphydrioidea and Xyeloidea are combined as one checklist section, as the sawflies represent a distinctive assemblage of phytophagous (except Orussidae) Hymenoptera. More than fifty years have passed since the publication of the final part of Robert B. Benson’s three part identification key to the “Symphyta” of the British Isles (Benson 1935, Benson 1952, Benson 1958). Whilst the first two parts were based substantially on the acute monography by Eduard Enslin (Enslin 1912, Enslin 1913, Enslin 1914, Enslin 1915, Enslin 1916, Enslin 1917 and Enslin 1918), Benson’s treatment of the Nematinae represented an original and significant step forward in our knowledge of this subfamily. The results of subsequent research on the British and Irish sawfly fauna were collated by Quinlan (1978). Since then, renewed investigation of the taxonomy of West Palaearctic sawflies has led to a great number of taxonomic and nomenclatural changes, affecting many taxa occurring in the British Isles. Of particular value in accessing the extensive but widely scattered literature on sawflies, is the online database “Electronic World Catalog of Symphyta (ECatSym)” (Blank et al. 2012). Unfortunately, the only identification guide to the European “Symphyta” published since 1958 with a more than local geographical scope, by Zhelochovtsev (1988), suffers from weaknesses, such as the reliance placed on the opinions and illustrations of E. Lindqvist in its treatment of the Nematinae. Mistakes in translation from Russian make the later English language edition of this work even more difficult to use. Special problems are attached to the interpretation of records for some species not found in the British Isles since their inclusion in the works of Leach (1817) and Stephens (1835). Some of these are probably extinct, but their presence in the British Isles has in many cases never been unequivocally proved: see for example Benson (1943). We therefore maintain the practice, as in Fitton et al. (1978), of marking names of such taxa with a preceding “?”. Further, the taxonomic status of some of the nominal taxa described from the British Isles by Hill, Stephens, Newman and Cameron is still unclear, particularly where no type material has been located. The number of confirmed British sawfly species now stands at 537, compared to 471 in the 1978 checklist (Quinlan 1978; Broad 2014). Note that, since the publication of the introduction section (Broad 2014) a further family, Heptamelidae, has been recognised (Malm and Nyman 2014), including two British species previously included in Tenthredinidae. Authorship and date of publication of original descriptions by various authors follow mainly the bibliographic research of Taeger and Blank (1996), Taeger and Blank (2006), Blank and Taeger (1998), Blank et al. (2009) and Taeger et al. (2010). The classification of genera used here is largely based on the system of Benson (1951-1958). This has the advantages of being relatively simple and widely known. Detailed phylogenetic studies on several major lineages of Tenthredinidae are still lacking. However, some definite conclusions on generic groupings were reached by Nyman et al. (2006) on the Nematinae and Leppanen et al. (2012) on the Fenusini of the Blennocampinae. For the higher Nematinae, the full taxonomic and nomenclatural consequences of the recently proposed phylogeny have not yet been drawn. Far fewer genera will in future be recognised. For the present, we revert here to a generic classification that is similar to that used by Benson (1958), even though we are aware that Pachynematus, for example, is not monophyletic. Genus and species group names are included selectively in the synonymy. For a complete current synonymy of all these, including important misidentifications, see ECatSym (Blank et al. 2012). A name is only included as a synonym when it fulfils one or both of the following criteria: has at some time been used for a taxon occurring in the British Isles; is used in widely consulted works on taxonomy or distribution, or in original accounts of biological characters / descriptions of immature stages. The general scope and rationale for the checklist are covered by Broad (2014). As for the rest of the checklist, the Channel Islands fauna is excluded: see Sheppard (1990) on the sawfly fauna of the Channel Islands. There is a lack of data on the sawflies of the Isle of Man. It should be noted that several species were mistakenly listed as occurring in Scotland by Liston (1995). Some of the diversity of British sawflies is illustrated in Figs 1, ​,2,2, ​,3,3, ​,44. Representative British sawflies, superfamilies Cephoidea, Pamphilioidea and Siricoidea. Figure 1a. Cephidae, Phylloecus xanthostoma (G. Knight)