Distribution, nymphal habitat, genetic structure and conservation of the New Zealand mayfly Isothraulus abditus (Insecta: Ephemeroptera) and a description of its subimago

Distribution, nymphal habitat and genetic structure of the New Zealand mayfly Isothraulus abditus were investigated to improve our understanding of its ecology and conservation status. A description of the undescribed subimaginal stage is also provided. Isothraulus abditus has now been recorded from 55 North Island streams, 47 being new to published literature. Its distribution currently extends from Mangonui in Northland to Taumatatahi near Whanganui. Nymphs live in forested stream pools and backwaters containing organic detritus. Genetic structure of six populations was assessed using the mitochondrial cytochrome c oxidase subunit I (COI) gene. Thirty-six haplotypes were identified from 123 individuals, and a maximum uncorrected genetic distance of 1.8% indicated that specimens belong to a single species. However, those within Northland showed some genetic differentiation. Restricted habitat, sparse distribution and some genetic differentiation of I. abditus suggest its conservation status should be classified as ‘At Risk’. LSID: urn:lsid:zoobank.org:pub:75C386BC-C0A5-4627-AE4B-8C5D749D53BA