Distribution and diversity of terrestrial isopods (Isopoda: Oniscidea) in Canada, including new records and a species checklist

Terrestrial isopods (Isopoda: Oniscidea), also known as sowbugs or woodlice, are one of the few groups of crustaceans with fully terrestrial members. Sowbugs are readily transported by human activity, with many species having been introduced worldwide. Although nonnative sowbugs have been present in Canada for more than 150 years, the study of sowbugs in Canada has been largely overlooked, especially in the Prairie Provinces. We conducted the first survey of sowbug species in Alberta, with additional collections from British Columbia, Saskatchewan, Ontario, and Newfoundland. We compiled an updated Canadian species checklist of 32 species from 12 families, including seven new species records for Canada since the previous 2001 checklist. Species with older records tend to occupy more provinces than species recorded more recently. Nine sowbug species occur in Alberta: all are nonnative and originate from Europe or Asia. Our collection of Nagurus cristatus (Dollfus, 1899) (Trachelipodidae) from Edmonton represents the first record from Canada. We support our identifications with molecular data (cytochrome c oxidase subunit 1 barcode region). Further surveys of sowbugs in the Prairie Provinces may uncover additional species; we encourage reporting of sowbug bycatch from arthropod surveys and note the utility of community science platforms for conducting sowbug surveys.