The insect superfamily Psylloidea (Hemiptera) includes economically important biocontrol agents, pests and plant pathogen vectors, for which a rapid and accurate identification is fundamental for international biosecurity. Australasia is a hot spot for psyllid diversity, but previous species assessments in the region were largely based on morphology and host plant association. Morphological identification of psyllids remains challenging for a wide number of species and for juvenile insects, while a robust molecular framework for identification is not available. Consequently, knowledge of psyllid biology is compromised. Here, incorporating morphological evidence and host plant associations, insects collected from almost 600 primarily New Zealand locations were linked to 67 previously described species. By applying species delimitation methods including GYMC (General Mixed Yule-Coalescent method), PTP (Poisson Tree Processes), mPTP (multi-rate Poisson Tree Processes) and ABGD (Automatic Barcode Gap Discovery) to a dataset composed of 425 cytochrome oxidase I (COI) DNA barcode sequences, further cryptic diversity was revealed among the psyllid collection; more than 20 undescribed taxa are reported here for the first time, resulting in a total of 90 taxa across 21 genera and six families included in this study. Our improved understanding of psyllid diversity in New Zealand revealed new plant host-psyllid associations and geographical variation. The DNA barcode resource will enable future studies of psyllid ecology and more accurate, rapid identifications of psyllids that pose biosecurity threats to Australasia.

A checklist of extant species of Psylloidea in New Zealand is presented. The list is structured according to the latest taxonomic classification of families, subfamilies and genera. It includes 99 species, 71 of which are formally described and named, along with information on the host plants and the natural enemies as aspects that are either species-specific or assist in their recognition. An updated distribution of each species is given based on literature records and material held in the major New Zealand entomological collections and databases, including from very recent field surveys. A new record for New Zealand is Phellopsylla formicosa.