An updated classification of the jumping plant-lice (Hemiptera: Psylloidea) integrating molecular and morphological evidence Author Burckhardt, Daniel 2FA5C7E5-D28E-4220-9796-02717E892B1D Naturhistorisches Museum, Augustinergasse 2, 4001 Basel, Switzerland. ANSES, Plant Health Laboratory, Entomology and invasive plants unit, 755 avenue du campus Agropolis, CS 30016, 34988 Montferrier-sur-Lez Cedex, France. Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver V 6 T 1 Z 4, Canada. daniel.burckhardt@bs.ch Author Ouvrard, David 2748132A-5D53-4BBA-9E33-F2723DCAAF19 david.ouvrard@anses.fr Author Percy, Diana M. 84F3C908-9927-40A6-BBBF-6951B7736278 diana.percy@ubc.ca text European Journal of Taxonomy 2021 2021-03-05 736 137 182 http://dx.doi.org/10.5852/ejt.2021.736.1257 journal article 7787 10.5852/ejt.2021.736.1257 64d18d39-b7e3-4331-9a2a-354b0d894546 2118-9773 4594332 F2976039-934E-46BE-B839-4D28C92C871F Superfamily Psylloidea Latreille, 1807 Percy et al . (2018) presented two mitogenome (mtg) phylogenies that we refer to here as the AN tree (‘allnucleotide’ tree) and the CC tree (‘conserved-codon’ tree), as well as a much reduced taxon sampling using a nuclear genome analysis, and a combined mitochondrial and nuclear data analysis. Due to the greater taxon sampling for the mitogenome analyses, we refer mostly to these results here. The results of Cho et al . (2019) are similar to the AN tree. In the main, analyses in Percy et al . (2018) and Cho et al. (2019) had considerable congruence, with notable exceptions discussed below. Both mtg trees are similar and recover the same crown groups. The major difference lies in the basal groupings. The Aphalaridae Löw, 1879 , as defined here, is a paraphyletic basal assemblage in the AN tree (also paraphyletic in Cho et al . 2019 ) and a poorly supported monophylum in the CC tree. Carsidaridae Crawford, 1911 (including Pachypsylla ) and Homotomidae Heslop-Harrison, 1958 form a poorly supported sister group in the AN tree and a paraphyletic, basal assemblage in the CC tree. The former hypothesis (i.e., sister family relationship between Carsidaridae (without Pachypsyllinae Crawford, 1914 ) and Homotomidae ) is supported by two putative morphological synapomorphies ( Hollis & Broomfield 1989 ) and is recovered with stronger support in the nuclear genome data in Percy et al . (2018) as well as combined data in Cho et al . (2019) . In both mtg trees, the Mastigimatinae Bekker-Migdisova, 1973 constitutes the sister group to a well supported (94%) clade comprising the Liviidae Löw, 1879 , as defined here, and the PTCD clade ( Psyllidae , Triozidae Löw, 1879 , Calophyinae Vondráček, 1957 sensu Burckhardt & Ouvrard (2012) , Diaphorina Löw,1880 and Katacephala Crawford, 1914 ). This grouping differs from that of Burckhardt & Ouvrard (2012) who included Mastigimatinae in their artificial Calophyidae . For this reason, Mastigimatinae is removed from Calophyidae and given family rank here. This move is supported by Cho et al . (2019) although the phylogenetic placement of Mastigimatinae is not identical. The Liviidae , as defined here, is a poorly supported monophylum in the AN tree and paraphyletic in the CC tree. It is also recovered as paraphyletic in combined data analyses in both Percy et al. (2018) and Cho et al . (2019) . In both mtg trees, the PTCD clade is very strongly supported (100%) (consistent with Cho et al . 2019 ), and Calophyidae Vondráček, 1957 (without Mastigimatinae ) constitutes the sister taxon of the remainder of taxa in the PTCD clade with good (AN tree) or poor support (CC tree); notably, an alternative placement of Calophyidae as sister to Triozidae (albeit with mixed support) in combined data analyses in both Percy et al . (2018) and Cho et al . (2019) serves to emphasise that phylogenetic placement within the PTCD clade awaits robust confirmation. The support of the monophyly of Psyllidae (including Diaphorina and Katacephala ) is good (AN tree) or poor (CC tree) and that of Triozidae very strong in both trees (99%). Again, due to ambiguity in the placement of Diaphorina in the combined data analysis in Percy et al . (2018) , additional analyses will be required for robust confirmation. In summary, not all taxonomic groups recognized here are strongly supported as monophyla in all or any of the molecular analyses, in some cases we have erred on the side of providing a practical and stable classification, particularly where ambiguity in molecular analyses remains. A summary of family interrelationships adopted here is shown in Fig. 1 .